Latest / Daniel and Kelly’s Extraordinary Universe / Was the Tyrannosaurus rex fast or slow? (Featuring Dr. John Hutchinson)

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Was the Tyrannosaurus rex fast or slow? (Featuring Dr. John Hutchinson) · Daniel and Kelly’s Extraordinary Universe

0:05
Speaker 1: When I was a kid, I was absolutely obsessed with
0:08
Speaker 1: Jurassic Park. It wasn't just because of the dreamy Ian Malcolm,
0:13
Speaker 1: but mostly was because I desperately wanted to be a paleontologist.
0:18
Speaker 1: The idea of bringing long extinct animals back to life
0:21
Speaker 1: through the magic of biology was absolutely infraling to me,
0:25
Speaker 1: and I went to the cheap theater to watch Jurassic
0:27
Speaker 1: Park on the big screen as often as my mom
0:30
Speaker 1: was willing to take me. The scene where the t
0:32
Speaker 1: Rex is chasing the jeep carrying the injured Ian Malcolm
0:36
Speaker 1: to safety is burned into my memory. But even as
0:39
Speaker 1: a kid, I remember watching that scene and wondering to myself,
0:43
Speaker 1: could an animal that big really go that fast? If so,
0:48
Speaker 1: why is the huge Brontosaurus not similarly swift. This is
0:52
Speaker 1: a difficult question to answer, After all, how do you
0:55
Speaker 1: even go about figuring out how an extinct animal moved
1:00
Speaker 1: around to be videotaped anymore? And the muscles that hold
1:04
Speaker 1: keys to answering questions like these have long since decayed away. Well.
1:08
Speaker 1: On today's show, we're talking to doctor John Hutchinson, who
1:11
Speaker 1: studies the movement of long dead animals. While answering amazing
1:16
Speaker 1: questions like can hippos get airborne? And how do elephants run?
1:21
Speaker 1: This is the perfect topic for Daniel and Kelly's Extraordinary
1:24
Speaker 1: Universe because it's the happy intersection of biology and physics.
1:29
Speaker 1: Welcome to Daniel and Kelly's Extraordinarily fast Moving Universe.
1:47
Speaker 2: Hi. I'm Daniel. I'm a particle physicist, and I've always
1:49
Speaker 2: considered myself a large animal.
1:53
Speaker 3: Hi.
1:53
Speaker 1: I'm Kelly Wiener Smith. I'm a biologist and I sort
1:56
Speaker 1: of fluctuate between being a large and a larger animal.
2:00
Speaker 1: It depends on how close we are to the holidays.
2:02
Speaker 1: But I always feel great about myself, so it's all good.
2:06
Speaker 2: And so, Kelly, what do you think is your top
2:08
Speaker 2: land speed or what could Kelly outrun? Let's put it
2:15
Speaker 2: that way.
2:16
Speaker 1: I've definitely outrun some turtles on the property.
2:19
Speaker 2: And that's good. Let's start there.
2:21
Speaker 1: There are some fast frogs on the properties, so maybe
2:25
Speaker 1: somewhere in between those things.
2:28
Speaker 2: Wow, are you telling me a swarm of frogs could
2:30
Speaker 2: take you down?
2:31
Speaker 3: Oh?
2:32
Speaker 1: I mean they could catch up to me, but they're
2:35
Speaker 1: pretty tiny, you know. I think I could give them
2:37
Speaker 1: a couple good swift kicks. I have taken some taekwondo,
2:40
Speaker 1: so maybe I can give them a couple of chops.
2:42
Speaker 2: All right, so all frog listeners be warned. Kelly can
2:45
Speaker 2: defend herself. Yeah, I'm not a very fast person. I
2:48
Speaker 2: could not outrun a cat or a dog or even
2:52
Speaker 2: a rat. I've chased a rat around our garage and
2:54
Speaker 2: lost that race rather surprisingly fast. But to my credit,
2:58
Speaker 2: I do have offspring surprisingly fast. My son is a runner,
3:02
Speaker 2: and he runs a mile and shockingly four minutes and
3:05
Speaker 2: twenty seconds or something, and so I think I want
3:08
Speaker 2: to take some credit for that, even though it's probably
3:10
Speaker 2: more likely to be cosmic ray mutation or transcription errors
3:14
Speaker 2: or something that led to that.
3:16
Speaker 1: You're one of those parents whose children's accomplishments are your accomplishments.
3:21
Speaker 2: Absolutely, while I's have kids, I put his times on
3:25
Speaker 2: my CV for sure.
3:28
Speaker 1: Does that help? What's funding? I can't imagine it would.
3:31
Speaker 2: It doesn't. No, it's wonderful to see your kids grow
3:35
Speaker 2: up and just have different skills and interest than you do.
3:38
Speaker 2: It's fantastic and also surprising sometimes.
3:41
Speaker 1: Yes, No, my son has amazing abs, Like you can
3:44
Speaker 1: put him in any position and he can sort of
3:46
Speaker 1: lift himself up with his core and it's crazy. And
3:49
Speaker 1: my daughter's starting her first math competition. Both of those
3:52
Speaker 1: things are My kids are amazing, and I had something
3:55
Speaker 1: to do with it, But I don't know how much
3:57
Speaker 1: credit I get for either of those things.
4:00
Speaker 2: Our biology is complicated, right.
4:02
Speaker 1: They tell yep, yep, it's true. And you know another
4:05
Speaker 1: thing that's complicated is how do you portray biology in
4:09
Speaker 1: movies and TV shows, especially when you're really pushing the
4:12
Speaker 1: boundaries of the biology. And we have a really great
4:16
Speaker 1: question about that today from a listener. Let's go ahead
4:18
Speaker 1: and hear it.
4:20
Speaker 4: Hi, there, Daniel and Kelly. It's been from Melbourne in
4:23
Speaker 4: Australia here, and I've got a question about large creatures,
4:27
Speaker 4: including giant people, and how they move. So I've noticed
4:32
Speaker 4: in a lot of movies and TV shows when something
4:35
Speaker 4: giant is depicted, like giant ant Man in the Marvel movies,
4:41
Speaker 4: they're often depicted as moving really slow, kind of like
4:44
Speaker 4: in slow motion. But then in other media we've got
4:48
Speaker 4: giant things like the Ava units in the Evangelian anime,
4:53
Speaker 4: which move really really fast. And it got me wondering,
4:56
Speaker 4: is there any physics reason or any biol raisin why
5:02
Speaker 4: one of those depictions is accurate as opposed to the
5:06
Speaker 4: other or does it depend on the particular case. Really
5:10
Speaker 4: enjoy the podcast and really looking forward to what you
5:12
Speaker 4: might have to say.
5:14
Speaker 1: So this is an amazing question. And I was so
5:16
Speaker 1: excited when I got this question because I had somewhat
5:19
Speaker 1: recently met a professor who studies very large animals, and
5:23
Speaker 1: we were in a meeting with a bunch of other
5:25
Speaker 1: people and there were things going on, and I didn't
5:27
Speaker 1: get a chance to ask him all the questions that
5:29
Speaker 1: I wanted to ask him about his research. So I
5:31
Speaker 1: was so excited to have an excuse to invite him
5:33
Speaker 1: on the show. And so today we have doctor John
5:36
Speaker 1: Hutchinson on the show to tell us all about how
5:38
Speaker 1: very large animals move and.
5:40
Speaker 2: What a giraffe burger taste like hmmm.
5:48
Speaker 1: Doctor John Hutchinson is a professor of evolutionary biomechanics and
5:51
Speaker 1: a Fellow of the Royal Society. His research straddles the
5:55
Speaker 1: fields of evolutionary biology and biomechanics, with an emphasis on
5:58
Speaker 1: how very large animals stand and move, and how locomotion
6:02
Speaker 1: evolved in different groups of land vertebrates. Welcome to the show, John,
6:06
Speaker 1: Thank you very much.
6:07
Speaker 2: Kelly, Kelly in your introduction, you neglected to mention that
6:10
Speaker 2: John also has an incredible array of heads on the
6:13
Speaker 2: wall behind him.
6:16
Speaker 1: Well, I didn't know that when I wrote the intro.
6:18
Speaker 2: What's going on there?
6:19
Speaker 3: Yeah, that's my mask and collection. Oh cool, which got
6:22
Speaker 3: particularly ironic early in the COVID pandemic, But it only
6:27
Speaker 3: encouraged my collection of masks.
6:29
Speaker 2: So for those of you just listening, we see octopus
6:33
Speaker 2: and what else is going on with giraffe?
6:35
Speaker 1: Thulu Giraffe? Are these all from places that you visited?
6:39
Speaker 3: Just random places, often just gifts from people, or I
6:42
Speaker 3: find them like at a arts sale kind of thing
6:47
Speaker 3: or whatever.
6:48
Speaker 2: I don't know why you don't just wear them when
6:49
Speaker 2: you jump onto a zoom call. That'd be very dramatic.
6:54
Speaker 3: Some of them.
6:56
Speaker 1: All right, Well, let's pull back and talk about what
6:59
Speaker 1: got you into in studying the movement of very large animals.
7:03
Speaker 3: It really goes back I think to being a high
7:06
Speaker 3: school student in a physics class, and I remember my
7:12
Speaker 3: teacher had like a bulletin board with some news articles
7:15
Speaker 3: or something on it. That's the way I remember it.
7:18
Speaker 3: And one of them explained why King Kong and Godzilla
7:21
Speaker 3: were physical impossibilities because they were just too big to
7:25
Speaker 3: support their own weight. And I was a big, big
7:28
Speaker 3: monster movie fan, just way too early for my years,
7:32
Speaker 3: really into Kaiju type movies. And that was really interesting
7:38
Speaker 3: to me because it made me grapple with my growing
7:42
Speaker 3: interest in science and my longstanding interest in the arts
7:48
Speaker 3: and fiction. So I had to think about, Oh, wow,
7:52
Speaker 3: that actually really makes sense, but too bad.
7:55
Speaker 1: And you were like, one day, I'm going to crush
7:57
Speaker 1: dreams just like the author of that article.
8:00
Speaker 2: Yes, walk us to the argument, why does physics say
8:04
Speaker 2: that biology can't get too big?
8:06
Speaker 3: The simplest explanation is what they call the square cube law. Well,
8:12
Speaker 3: there's various terms for it. But as animals get bigger,
8:15
Speaker 3: their wet mass or their weight goes up by a
8:18
Speaker 3: linear dimension cubed. So you have a length, a width,
8:21
Speaker 3: and a height. That's your mass, your volume so forth,
8:25
Speaker 3: so that increases with your size. Overall, mass is a
8:30
Speaker 3: metric of size more or less. But as your mass increases,
8:35
Speaker 3: your area your linear dimensions squared, So cross sexual area
8:39
Speaker 3: only goes up proportionately by the linear dimension squared, so
8:46
Speaker 3: very quickly, the amount of weight you support on a
8:49
Speaker 3: given area gets higher and higher and higher, unless you
8:53
Speaker 3: do something to change your mechanics of movement.
8:59
Speaker 2: So let me interpret that. Assume, for example, we have
9:01
Speaker 2: a spherical godzilla, right, solways like to assume spherical monsters.
9:07
Speaker 2: Then you're saying the volume of that sphere goes with
9:10
Speaker 2: the radius cubed right, it's like four thirds pi r cube.
9:14
Speaker 2: But the surface area of the sphere is four pi
9:17
Speaker 2: r squared. And so when you double the radius, the
9:20
Speaker 2: volume goes up by eight, but the surface area only
9:23
Speaker 2: goes up by four. And as that continues, as the
9:26
Speaker 2: radius goes up and up and up, and you get
9:28
Speaker 2: to actual gun zilla sizes, the ratio gets larger and
9:30
Speaker 2: larger a volume to surface area. But why is that
9:34
Speaker 2: a problem, Like why is it a big issue to
9:36
Speaker 2: have a lot of wet mass inside your surface area?
9:39
Speaker 3: Because of biology? Because animals are made of the same
9:43
Speaker 3: stuff that has intrinsically the same mechanical properties, the same strength. Fundamentally,
9:49
Speaker 3: that's the most important thing. See the amount of forest
9:53
Speaker 3: per unit area a bone or a muscle can support
9:57
Speaker 3: is fairly constant. A vertebrates that move on land in particular,
10:03
Speaker 3: because this is all operating under gravity. Is assumption if
10:07
Speaker 3: once animals get into the water, all bets are off.
10:10
Speaker 3: It's effectively zero gravity more or less. So then this
10:13
Speaker 3: square cube law is not such a concern. On land,
10:17
Speaker 3: the strength of tissue becomes fundamental.
10:20
Speaker 1: Is the limiting factor there mostly bone or mostly muscle,
10:24
Speaker 1: or it has to be both. What limits what an
10:27
Speaker 1: animal can hold?
10:28
Speaker 3: I think this is still a big question in science
10:32
Speaker 3: that you would think it might be bone because bones
10:36
Speaker 3: are there to support body weight against gravity. But bones
10:40
Speaker 3: form joints that muscles act around to support animals. So
10:44
Speaker 3: there's the living component, the contractile component of support, which
10:49
Speaker 3: is muscle, But then there's all the other passive stuff bone,
10:52
Speaker 3: ligaments and cartilage and so forth. It also provides support.
10:55
Speaker 3: And what we don't really understand yet is how much
10:59
Speaker 3: of a role each of those things plays and how
11:01
Speaker 3: that balance changes as animals get bigger. One thing we
11:05
Speaker 3: do know is that as animals get bigger land animals,
11:10
Speaker 3: I should specify land vertebrates, As they get bigger, they
11:13
Speaker 3: tend to straighten their legs, so that shifts their mechanics
11:18
Speaker 3: of support to using their legs more and more and
11:21
Speaker 3: more like pillars, which transmits more of the force down
11:24
Speaker 3: the long axis of the bone. So like when we stand,
11:27
Speaker 3: we're using our legs like pillars. More or less. We're
11:30
Speaker 3: quite unusual actually for animals of our size, and the
11:33
Speaker 3: way we do that, it's very efficient, providing a lot
11:36
Speaker 3: of passive support. So mostly the bones are providing allow
11:39
Speaker 3: of support once you get to a very very pillar
11:42
Speaker 3: like posture, whereas intermediate postures with more bending of the
11:47
Speaker 3: limbs would involve presumably more muscle activity. But you know,
11:51
Speaker 3: this is hard to figure out because there are so
11:53
Speaker 3: many components acting around each joint in any real organism.
11:58
Speaker 3: It's a really difficult mathematical problem.
12:01
Speaker 2: So my takeaway is that it's not necessarily impossible to
12:04
Speaker 2: have any given size of animal, but that the task
12:08
Speaker 2: of the animal, the sort of biological engineering needed changes
12:11
Speaker 2: as the animal gets bigger or smaller. Because of these
12:14
Speaker 2: different ratios and the strategies that we have, are vertebrates
12:17
Speaker 2: on Earth might not scale to like really big godzillas.
12:21
Speaker 2: But does that mean, for example, you couldn't have a
12:23
Speaker 2: fundamentally different biology, you know, some crazy hollow thing or
12:27
Speaker 2: different kind of biological engineering or no joints or I
12:30
Speaker 2: don't know, something you know really out of this world
12:33
Speaker 2: that could allow for much much larger animals.
12:36
Speaker 3: That is a great question, like in terms of like
12:39
Speaker 3: other worlds or such. Certainly we don't know what tissue
12:42
Speaker 3: could achieve. We only know what's there.
12:44
Speaker 1: So Daniel was asking, are there different ways to get bigger?
12:48
Speaker 1: Like can you hollow out your inside or something you
12:50
Speaker 1: mentioned in water is effectively zero gravity. Does that mean
12:55
Speaker 1: that blue whales, like we could have something a hundred
12:59
Speaker 1: times bigger than that, or does something else limit size
13:02
Speaker 1: in the ocean?
13:03
Speaker 3: This is another big question. We don't understand. We don't
13:05
Speaker 3: understand what the upper limit of size is on land
13:08
Speaker 3: or in water or anything. We only know what we see.
13:12
Speaker 3: And the largest animal ever so far is the blue whale.
13:16
Speaker 3: There are some fossils that kind of seem to maybe
13:19
Speaker 3: come close to that in size, but blue whales are
13:22
Speaker 3: the biggest. But it doesn't mean that animals can't get
13:25
Speaker 3: any bigger than that. It's just that that's what evolution
13:28
Speaker 3: has produced. And certainly there are other mitigating factors like physiology,
13:33
Speaker 3: cardiovascular issues, breathing, ecology. So food is a huge constraint
13:40
Speaker 3: on body size. If you don't have enough food around,
13:43
Speaker 3: if you're in an unstable environment where food resources are crashing,
13:47
Speaker 3: all the time, like in the face of environmental change.
13:51
Speaker 3: Then being big is a very terrible biological strategy, so
13:55
Speaker 3: to speak. So large body size has many limits, not
14:00
Speaker 3: only the only the physical. There is a whole different
14:03
Speaker 3: body plan out there that we can look to in
14:06
Speaker 3: nature to ask questions about mechanics of size and support,
14:11
Speaker 3: and that's arthropods. What's really interesting is that even in
14:15
Speaker 3: the most extreme cases in the fossil record, we see
14:18
Speaker 3: no gigantic arthropods.
14:21
Speaker 2: Remind me, what's an arthropod.
14:22
Speaker 3: Animals with exoskeletons, So insects, crabs, crustaceans, spiders, and so forth,
14:28
Speaker 3: things with their skeleton on their outside.
14:30
Speaker 2: So no lobsters the size of blue whale so far.
14:33
Speaker 3: Yeah. Yeah. So they keep their muscles on the inside,
14:36
Speaker 3: which constrains how big their muscles can be because they've
14:39
Speaker 3: got to have not only all their muscle on the inside,
14:42
Speaker 3: but all the other stuff. They're a circulatory system, so
14:45
Speaker 3: on and so forth, so that constrains them to a
14:48
Speaker 3: certain degree. But also other factors like their circulatory system,
14:51
Speaker 3: constrain their size. So they are weirdos. But also arthropods
14:57
Speaker 3: are weirdos because their muscles break all the rule of
15:00
Speaker 3: what muscles can do. I talked about vertebrate muscle having
15:04
Speaker 3: pretty much the same properties across any size of vertebrate,
15:09
Speaker 3: but insect muscles have tremendous variation in what kind of
15:14
Speaker 3: properties they can have, but they still could not enable
15:17
Speaker 3: like a fifty ton ant.
15:20
Speaker 1: Oh there was a movie when I was a kid
15:22
Speaker 1: that had a giant ant after a new bar more
15:25
Speaker 1: and yeah them, Oh, oh, you've crushed my dreams. I
15:29
Speaker 1: was really hoping that that would be a silver lining.
15:31
Speaker 3: I think I specifically chose that to crush your dash man.
15:34
Speaker 1: Well, good job, good job.
15:36
Speaker 2: Spot on a little taste of your own medicine there, Kelly.
15:39
Speaker 1: Oh ouch, could you tell us a little bit more
15:42
Speaker 1: about the different kinds of insect muscles how do they
15:44
Speaker 1: break the rules? Or arthropod muscles?
15:47
Speaker 3: Okay, this is getting outside of my expertise a bit,
15:50
Speaker 3: but they have really different sizes and proportions of proteins
15:55
Speaker 3: that make up muscle. There are three major proteins that
15:57
Speaker 3: make up muscle actin myosin and and those three molecules
16:02
Speaker 3: interact to produce these sliding filaments that lengthen and shorten
16:07
Speaker 3: the muscle unit called the sarkamre. Invertebrates, they're all kind
16:12
Speaker 3: of made the same, but in insects, they're built in
16:15
Speaker 3: different ways. They can contract at different rates, they can
16:18
Speaker 3: do all kinds of crazy stuff, and I can't explain
16:20
Speaker 3: that to you. I'm not an insect muscle physiologist. I
16:24
Speaker 3: have huge respect for them because they studied things that
16:27
Speaker 3: are really weird to me.
16:29
Speaker 2: Can I admit something that may be embarrassing? Yeah, I
16:31
Speaker 2: didn't know until this conversation that insects had muscles. My
16:35
Speaker 2: mental image was that they just basically had some sort
16:38
Speaker 2: of hydraulic goo inside their exoskeletons, and I had no
16:41
Speaker 2: idea how they moved. So that's fascinating. Are you saying
16:46
Speaker 2: it's like differentiated inside there? Like if I cut into
16:48
Speaker 2: a fifty ton ant, It's not just like a fire
16:51
Speaker 2: hose of goo that's going to spread out.
16:53
Speaker 3: No, no, No, they have plenty of internal structure. Spiders
16:56
Speaker 3: do move using a largely hydraulic limb structure, so they
17:01
Speaker 3: have muscles, but they're mostly powering their leg movements through
17:04
Speaker 3: a hydraulic movement that's coupled to their circulatory system, so
17:09
Speaker 3: they're pumping fluid around their bodies. And using that fluid
17:12
Speaker 3: to move their legs.
17:13
Speaker 2: So are muscles conserved across all animals? Like everything that's
17:18
Speaker 2: mobile on Earth uses some kind of muscle.
17:21
Speaker 3: Yeah, every animal. There are other things that do weird stuff.
17:25
Speaker 3: I guess once you get down to a single cell,
17:28
Speaker 3: it becomes a question of what really is a muscle.
17:31
Speaker 3: H becomes a little weird. I mean, you're using proteins
17:33
Speaker 3: to spin a flagella, a little whip like structure in
17:37
Speaker 3: bacteria and other small small organisms. So I think if
17:42
Speaker 3: we're talking about muscle in the way that we're familiar
17:45
Speaker 3: with it, with the three major components acting miosin Titan,
17:48
Speaker 3: then that's an animal thing more or less.
17:50
Speaker 2: And so on that topic, why don't we have like
17:53
Speaker 2: macroscopic sized bacteria. Why don't we see the ocean filled
17:57
Speaker 2: with like blue whales and then like bacteria the size
18:00
Speaker 2: blue whale with a massive flagella behind it. Oh boy,
18:03
Speaker 2: and hack, nobody's made that monster movie yet. That's the
18:06
Speaker 2: real question.
18:06
Speaker 3: Yeah, Well, I mean the blob was kind of in
18:10
Speaker 3: that direction of the I don't know how you classify
18:15
Speaker 3: that blob, although if you know your HP lovecraft lore,
18:19
Speaker 3: it was probably a shagoth anyway. Yeah, bacteria, I don't
18:25
Speaker 3: know if I could give you an easy answer there.
18:27
Speaker 3: I think diffusion would be a big problem for them.
18:30
Speaker 3: They've got this big, tough cell wall, and they're one
18:34
Speaker 3: cell that relies on stuff to get in and out
18:38
Speaker 3: of that cell wall and move around the organism. They
18:41
Speaker 3: have no respiratory circulatory systems anything like that. They just
18:45
Speaker 3: rely purely on diffusion. So I think that's going to
18:48
Speaker 3: be a big constraint on any single celled organism is diffusion.
18:52
Speaker 3: And maybe the support of their cell wall itself might
18:55
Speaker 3: just crumple under its own weight and they can't really move.
18:59
Speaker 3: I mean, take a huge flagellum to move a big
19:04
Speaker 3: bacterium through the water. I can't even imagine how the
19:06
Speaker 3: mechanics of that would work.
19:07
Speaker 2: I'm sure you can imagine it. Mister monster movie over there,
19:12
Speaker 2: for sure has the mental image.
19:14
Speaker 3: Give me a few million in VFX budget and I
19:16
Speaker 3: can imagine it.
19:17
Speaker 2: Yeah, done and done.
19:20
Speaker 1: Yes, oh yeah, because we've got loads of money.
19:23
Speaker 3: James Cameron, There you go.
19:25
Speaker 2: Welcome to Daniel and Kelly's production studio.
19:28
Speaker 1: There you go. So the conversation we've been having has
19:32
Speaker 1: gone between physics and biology a lot. So you clearly
19:35
Speaker 1: know a lot about both. And so after the break,
19:38
Speaker 1: I'm going to ask you to explain why biology is
19:41
Speaker 1: better than physics.
19:42
Speaker 5: Oh, if possible, the gauntlet has been thrown down.
20:03
Speaker 1: And we're back, all right. So, John, you know a
20:05
Speaker 1: bunch about physics a bunch about biology. Do you have
20:08
Speaker 1: a favorite or what do you love about the intersection
20:10
Speaker 1: of these fields.
20:12
Speaker 3: I do love the intersection. I love intersections of fields
20:15
Speaker 3: in general. I like to defy boundaries. I like to
20:19
Speaker 3: think about how a lot of boundaries we erect with
20:22
Speaker 3: our minds are false and they're just there as conveniences. So, however,
20:28
Speaker 3: in physics is physics, it's very easily circumscribable, much like
20:33
Speaker 3: mathematics is, whereas biology is fuzzier. I like that aspect
20:37
Speaker 3: of biology, maybe because I like fuzziness, although physics can
20:41
Speaker 3: get pretty fuzzy. I guess down at the weird end
20:43
Speaker 3: of scales. Maybe Daniel you can agree that or not.
20:47
Speaker 1: That's where Daniel lives. Yeah, at the weird end.
20:50
Speaker 2: Yeah, I'm at the weird end of everything.
20:53
Speaker 1: That's right.
20:54
Speaker 2: But you ended up a biologist, I mean by name,
20:56
Speaker 2: you're in the evolutionary biomechanics department, do you not like
21:00
Speaker 2: in a physics department doing biophysics? And I completely agree
21:03
Speaker 2: with you that these are artificial dotted lines that we
21:06
Speaker 2: draw on a smooth spectrum of natural curiosity. But I
21:10
Speaker 2: am curious why you ended up on one side of
21:12
Speaker 2: that then the other, like, why are biologists more likely
21:15
Speaker 2: to hire you than physicists?
21:17
Speaker 3: Oh, my training very much is in biology. Into my PhD.
21:21
Speaker 3: I am a biologist. Fundamentally. I can't claim to be
21:24
Speaker 3: a physicist. It's just not my training. I'm not an
21:26
Speaker 3: engineer or anything like that. I did do a postdoc
21:29
Speaker 3: in an engineering laboratory, which gave me a bit of
21:32
Speaker 3: street cred with that crowd and did teach me a
21:35
Speaker 3: lot about that kind of perspective with Newtonian mechanics. But yeah,
21:41
Speaker 3: I couldn't go work in a physics department. They could
21:43
Speaker 3: tell that I was an impostor.
21:46
Speaker 2: Now you'd just be like, Hey, what happens if we
21:48
Speaker 2: have a really high energy collisions of very large animals,
21:51
Speaker 2: two elephants running at each other at high speeds. Let's
21:54
Speaker 2: do that experiment, right, It's easy to be in the
21:56
Speaker 2: physics department.
22:00
Speaker 1: Well, can we get into the details of your day
22:02
Speaker 1: to day life studying this stuff. So like, when I
22:05
Speaker 1: think about studying movement in small mammals, I can imagine,
22:08
Speaker 1: for example, putting them in a CT scanner or an
22:10
Speaker 1: X ray machine. But you study animals that are just
22:13
Speaker 1: absolutely massive, and so presumably they don't stay still in
22:17
Speaker 1: those machines or there's no machines big enough. So how
22:19
Speaker 1: do you get your data?
22:20
Speaker 3: Well, I'm interested in the size spectrum of animals in general,
22:23
Speaker 3: because I don't think you can understand big animals without
22:26
Speaker 3: also understanding smaller ones. It's just that we do have
22:29
Speaker 3: a lot of knowledge of how smaller animals work, and
22:32
Speaker 3: just up until my work, there haven't been that much
22:35
Speaker 3: research on how the biggest land animals worked. So I
22:39
Speaker 3: do work on living animals using like X ray machines.
22:42
Speaker 3: We have multiple X ray video cameras as you can
22:45
Speaker 3: loosely call them, where you can have an animal moving
22:49
Speaker 3: through two planar X ray systems with high speed video
22:52
Speaker 3: cameras attached to them and use those in animation software
22:55
Speaker 3: to reconstruct how the skeleton moved in the living animal.
22:59
Speaker 3: That's really cutting edge stuff in our field. That allows
23:01
Speaker 3: us to see inside the animal and see it's skeleton
23:04
Speaker 3: moving in life. It's been a big game changer over
23:07
Speaker 3: the last twenty years. But yeah, we can't do that
23:10
Speaker 3: with big animals. The biggest size you can image is
23:13
Speaker 3: about soccer or football sized for Americans, soccer ball sized roughly,
23:19
Speaker 3: And the technology, for reasons I don't understand, or maybe
23:22
Speaker 3: just demand, has not created any machine that can do
23:25
Speaker 3: a volume bigger than that, So doing even small parts
23:30
Speaker 3: of big animals is impossible with that kind of stuff.
23:34
Speaker 3: We do more conventional kinds of study of larger animals
23:38
Speaker 3: with motion capture or just high speed video or whatever.
23:42
Speaker 3: We use other devices to measure how hard they exert
23:44
Speaker 3: force against their environments, so what we call force platforms
23:48
Speaker 3: and pressure pads that measure the force per unit area
23:51
Speaker 3: they apply to the grounds. We have lots of cool
23:53
Speaker 3: toys to measure what we would call the kinetics, so
23:56
Speaker 3: the forces and related things and the kinematics the motions
24:01
Speaker 3: of organisms.
24:02
Speaker 2: I'm confused when you say that you can only image
24:05
Speaker 2: something the size of a soccer ball, because like, you
24:07
Speaker 2: can put a whole human inside a CT machine, and
24:10
Speaker 2: there are some pretty big humans out there, why can't
24:13
Speaker 2: we do that with animals?
24:14
Speaker 3: Also, you can't have them moving around with like a
24:18
Speaker 3: video camera going on capturing data the a CT scan,
24:21
Speaker 3: you have to have individual remaining still because you're taking
24:25
Speaker 3: cereal slices cerial X rays of the individual to them
24:28
Speaker 3: piece together the whole three D person. So if they move,
24:31
Speaker 3: actually your image gets screwed up.
24:33
Speaker 2: I see. You can't convince an elephant to stay still.
24:36
Speaker 3: Yeah.
24:37
Speaker 1: Yeah, what's the biggest animal that you've studied.
24:40
Speaker 3: I've worked a bit on the big stopod dinosaurs. I'm
24:43
Speaker 3: not so well known for doing that, but I have
24:46
Speaker 3: published a bit on them with some colleagues. I'm more
24:49
Speaker 3: well known for studying the big carnivorous dinosaurs like t Rex.
24:52
Speaker 3: I really made my name with an early study I
24:55
Speaker 3: did showing that t Rex couldn't run quickly, again smashing dreams,
24:59
Speaker 3: making some pal petology fans rather upset, but it was
25:02
Speaker 3: well received scientifically, so I'm very pleased about that. I've
25:06
Speaker 3: worked with elephants a lot, about as much as I've
25:08
Speaker 3: worked on t Rex, and it's ken. I've worked on
25:11
Speaker 3: living elephants from zoos around the US and UK to
25:15
Speaker 3: more wild type elephants in Thailand, working with elephants that
25:20
Speaker 3: were either previously used in logging or tourism, or even
25:24
Speaker 3: used in racing. So I got to measure how the
25:28
Speaker 3: fastest elephants could move, which was really really cool.
25:31
Speaker 2: How fast can the elephant move?
25:33
Speaker 3: They can go up to almost fifteen miles an hour,
25:37
Speaker 3: which might not sound that fast, but that's a challenge
25:40
Speaker 3: for me to keep up with that pace. It's still
25:44
Speaker 3: pretty impressive to see like a four thousand kilogram animal
25:47
Speaker 3: traveling at fifteen miles an hour.
25:50
Speaker 2: That's a lot of kinetic energy.
25:51
Speaker 1: I bet it feels really fast if it's chasing you.
25:54
Speaker 3: Oh yeah. What we found with that work was that
25:58
Speaker 3: even though elephants don't go born at any time, when
26:01
Speaker 3: they go quickly, which is kind of what we thought,
26:04
Speaker 3: they do, sometimes only have support on one limb while
26:09
Speaker 3: the other three limbs are airborne, kind of doing the
26:12
Speaker 3: splits in mid air. So that was really cool to
26:15
Speaker 3: see how extreme the gate of elephants could be. They
26:18
Speaker 3: really do move in rather extreme ways even though they
26:21
Speaker 3: don't go fully airborne.
26:22
Speaker 2: That's fascinating. You talk about the gate of elephants like
26:25
Speaker 2: whether they're ever have all four legs off the ground. Yeah,
26:28
Speaker 2: animals do ever have all four legs off the.
26:31
Speaker 3: Ground pretty much everything except like tortoises and other really
26:35
Speaker 3: slow animals. And just this past summer we showed with
26:38
Speaker 3: another paper that when hippos go really quickly, they leave
26:42
Speaker 3: the ground with all four feet, which elephants don't. So
26:44
Speaker 3: that was a nice thing to find which had never
26:47
Speaker 3: been reported scientifically. We know that rhinos, which get very
26:50
Speaker 3: very big, up to three thousand kilograms or so, so
26:54
Speaker 3: rivaling the size of some like Asian elephants, they can gallop,
26:59
Speaker 3: they can leave the grind with all four feet, so
27:01
Speaker 3: they are kind of in that zone of being big
27:05
Speaker 3: and being athletic that is apparently hard to achieve.
27:08
Speaker 2: You discovered flying rhinoceurces. That's amazing.
27:12
Speaker 3: The rhino thing was known, but the fine hippo thing
27:14
Speaker 3: that was a small new contraction that I'm still proud
27:18
Speaker 3: of and got a lot of news attention. I was
27:20
Speaker 3: really kind of pleasantly surprised by that.
27:23
Speaker 2: I want to come back to the dinosaurs in a minute,
27:24
Speaker 2: but first I have a question about elephants, because I've
27:26
Speaker 2: always heard this story about elephants that the reason elephants
27:30
Speaker 2: have really big ears is because of this volume surface
27:33
Speaker 2: area of question. And you know you've scaled up the
27:36
Speaker 2: elephants to be so big, it's got so much meat
27:38
Speaker 2: it's hard for it to stay cool, and so having
27:40
Speaker 2: really big, flappy ears is like a cheap way to
27:42
Speaker 2: increase your service area without increasing your volume. Is that
27:46
Speaker 2: pop science nonsense or is that real science?
27:48
Speaker 3: There is some truth to that. So there's big differences
27:51
Speaker 3: in ear size in Asian versus African bush elephants. The
27:56
Speaker 3: bush elephants in Africa have much bigger ears that it
28:00
Speaker 3: corresponds to being out there in hotter temperatures in the open,
28:04
Speaker 3: exposed to sunlight and so forth. I think it's pretty
28:07
Speaker 3: well accepted that that difference in ear size and just
28:10
Speaker 3: the overall large ear size and elephants overall relates to
28:14
Speaker 3: them using the ears as the cooling mechanism, and they
28:17
Speaker 3: do wave their ears so they get convective cooling, moving
28:20
Speaker 3: the air quickly passed to ensure that there's always more
28:25
Speaker 3: air to unload the heat onto as they keep airflow going.
28:29
Speaker 1: And mammoths had little ears, right.
28:32
Speaker 3: Some wooly mammoths did, so. There are quite a few
28:35
Speaker 3: different species of mammliths. The wooly moth is the one
28:38
Speaker 3: we know best from animals preserved in frost, and Siberia
28:42
Speaker 3: had a lot of body parts reduced to avoid frostbite.
28:45
Speaker 2: Probably you know, I noticed that in Farside Far Side
28:49
Speaker 2: the mammoths always have kind of little cute ears, and
28:51
Speaker 2: I remember as a kid being like, is that right?
28:53
Speaker 2: So it's amazing Gary Larson ahead of his time.
28:56
Speaker 3: Oh he needs science. Yeah, he paid attention.
29:00
Speaker 1: Can I dig in a little bit more to your
29:01
Speaker 1: elephant study before we go to dinosaurs? So how did
29:04
Speaker 1: you figure out that the elephants had one foot on
29:07
Speaker 1: the ground at all time? Was it just a really
29:08
Speaker 1: good camera? And how do you make an elephant run
29:11
Speaker 1: on command? That sounds scary?
29:12
Speaker 3: It was just using pretty conventional cameras or not very
29:16
Speaker 3: high speed cameras. We did eventually get hold of some
29:19
Speaker 3: good cameras that helped confirm it even better. But when
29:22
Speaker 3: I was just a post doc or even a grad student, yeah,
29:25
Speaker 3: I was just like in my mid twenties, I started
29:28
Speaker 3: working on elephants trying to answer the question, well, do
29:31
Speaker 3: they leave the ground with all four feet or not?
29:33
Speaker 3: We didn't think so, but I wanted to test that empirically,
29:37
Speaker 3: and so I just took a video camera out to
29:39
Speaker 3: some zoos couldn't get them going quickly, and then got
29:43
Speaker 3: in touch with the guy in Thailand. He was interested
29:45
Speaker 3: in this kind of question, and I went out there
29:47
Speaker 3: with just a conventional video camera, and he knew all
29:50
Speaker 3: of the elephant keepers and just got them together and
29:53
Speaker 3: made it into kind of a game for them or
29:55
Speaker 3: a contest. So each elephant has its own companion, a
29:59
Speaker 3: mahout or a rider who pretty much grows up with
30:02
Speaker 3: the elephant, and they have a very strong bond in Thailand.
30:06
Speaker 3: And so the mahout would encourage the elephant by whatever
30:10
Speaker 3: means he thought was reasonable, like calling to it usually
30:14
Speaker 3: or having someone run in front of it, or have
30:16
Speaker 3: it go toward a friendly elephant, and that would motivate
30:20
Speaker 3: it to go quickly. It certainly did work in Thailand.
30:24
Speaker 3: We got much faster elephants than we ever did elsewhere.
30:27
Speaker 1: I love the idea of explaining to your thesis advisor.
30:30
Speaker 1: I couldn't answer the question. I couldn't get the elephants
30:32
Speaker 1: to go fast enough. It's a very unique problem.
30:36
Speaker 3: This is animal research. Yeahm Motivating animals very challenging.
30:40
Speaker 1: It's true.
30:41
Speaker 2: Do you have to get an IRB there, like do
30:44
Speaker 2: elephants get grumpy if you make them run, or can
30:46
Speaker 2: you probably hurt them or something.
30:48
Speaker 3: Yeah, there's always stringent ethical approval involved because even just
30:52
Speaker 3: stress is a concern. So you have to explain how
30:56
Speaker 3: are you going to mitigate stress? What are you going
30:58
Speaker 3: to do if an animal seems stressed? Will you terminate
31:00
Speaker 3: the experiment? What does stress look like? There are important questions,
31:04
Speaker 3: and avoiding fatigue also is really important. So we give
31:07
Speaker 3: animals lots of risk because we don't want to study fatigue.
31:09
Speaker 3: We want animals that are fresh.
31:11
Speaker 1: Let's go back to dinosaurs. You mentioned t rex right
31:14
Speaker 1: after we have finished talking about methods for looking at
31:17
Speaker 1: animal movement. But when you're studying dinosaurs, of course, you
31:21
Speaker 1: can't see them move at all. So how do you
31:23
Speaker 1: study animal movement in long dead animals?
31:26
Speaker 3: So we have kind of two things. We have the
31:30
Speaker 3: fundamental principles of animal movement that we know from living animals,
31:34
Speaker 3: which tell us some pretty good, reliable general rules that
31:38
Speaker 3: we can use as expectations to apply to extinct animals,
31:43
Speaker 3: or at least give boundaries for here's what this could
31:47
Speaker 3: be like. Here's how big the muscles might be relative
31:49
Speaker 3: to the limbs. That kind of thing and then we
31:53
Speaker 3: have physics, so we can and this is what I
31:56
Speaker 3: did in my PhD thesis, we can build either very
31:59
Speaker 3: simple or very complicated mechanical model of a dinosaur for
32:03
Speaker 3: its own sake. So actually try to reconstruct, like in
32:06
Speaker 3: a computer usually what the animal looked like, it's dimensions,
32:10
Speaker 3: and give those dimensions physical properties, mass, center of mass, inertia,
32:16
Speaker 3: so forth, stuff that physicists would care about, and then
32:19
Speaker 3: ask questions of that model, basically, what can you do
32:24
Speaker 3: what is possible with this representation of a dinosaur. And
32:29
Speaker 3: then you can test hypotheses like, well, given this set
32:32
Speaker 3: of assumptions about a t rex, could it run quickly
32:34
Speaker 3: or not? How much muscle mass would it have needed
32:36
Speaker 3: to run quickly? And is that reasonable given how much
32:39
Speaker 3: we could fit on the skeleton or not? And I
32:42
Speaker 3: tested that and found that no, it couldn't run very quickly,
32:45
Speaker 3: not like a racehorse, like twenty five miles an hour,
32:48
Speaker 3: but still possible to do more like kind of elephant speeds,
32:53
Speaker 3: maybe fifteen miles an hour, which for an animal that
32:55
Speaker 3: could get bigger than an elephant, it's still pretty darn good.
32:58
Speaker 2: So what you're doing here is like imagining how you
33:01
Speaker 2: might build a dinosaur saying like, well, how do reptiles
33:04
Speaker 2: move and how do current animals move? And you know
33:06
Speaker 2: the sort of shape of a dinosaur, so you're sort
33:08
Speaker 2: of imagining a biological model of a dinosaur then studying that.
33:12
Speaker 3: It's setting up a set of constraints. So here's what
33:16
Speaker 3: it's possible given what we know from living animals, the
33:19
Speaker 3: range of variation we see in living animals, which sometimes
33:22
Speaker 3: can be pretty conservative, and using that as inspiration to
33:27
Speaker 3: make assumptions about extinct animals. So we have the bones,
33:31
Speaker 3: that's direct information. Sometimes we have fossil footprints that we
33:34
Speaker 3: can use to kind of give an idea. Okay, this
33:37
Speaker 3: animal stood on two feet with the feet very close together,
33:40
Speaker 3: not sprawled out to either side. And yeah, so ultimately
33:45
Speaker 3: then we can, for example, reconstruct muscles attaching from bone
33:50
Speaker 3: to bone to guide their lines of action. And that
33:55
Speaker 3: can be done by looking at living animals and seeing, okay,
33:57
Speaker 3: where are the muscles of living animals attach? And I
34:01
Speaker 3: did a lot of that in my PhD work and
34:03
Speaker 3: found that if you look at living animals, especially the
34:07
Speaker 3: closest relatives to dinosaurs, like living birds and crocodiles and
34:11
Speaker 3: other reptiles. The leg muscles are really conservative, so you
34:17
Speaker 3: can pretty well predict where the muscles attach from the
34:21
Speaker 3: shape of the bones, from marks on the bones which
34:24
Speaker 3: reveal the actual interface between the muscler tendon and the
34:28
Speaker 3: bone itself.
34:29
Speaker 2: When you say conservative, you mean similar across species. Yeah,
34:33
Speaker 2: in small government.
34:35
Speaker 3: Yes, yeah, similar across species. So yeah, consistent and probably
34:41
Speaker 3: predictable that we can make assumptions about the anatomy of
34:44
Speaker 3: extinct animals that are reasonable. They're not going to be perfect,
34:47
Speaker 3: but they're pretty well grounded in actual evidence, and we
34:51
Speaker 3: can be very explicit. Well, I think it was this
34:53
Speaker 3: way because of these data that we have from living
34:56
Speaker 3: animals and this information that we have directly from the skeleton.
35:00
Speaker 2: The physicists in me likes that you're like building a
35:02
Speaker 2: model and exploring the speed and motion of that model,
35:06
Speaker 2: but then also wonders like what do we know about
35:08
Speaker 2: how that model might differ from real blinosaurs? Right, you
35:11
Speaker 2: are making assumptions and extrapolations. Then along with that you
35:15
Speaker 2: might develop like some uncertainty window or some band of
35:19
Speaker 2: your knowledge and confidence to say like, well, we're pretty sure,
35:22
Speaker 2: or is that something you can quantify, or is the
35:25
Speaker 2: information so sketchy that we can just sort of like
35:27
Speaker 2: make qualitative arguments about how well we know this stuff.
35:30
Speaker 3: It is difficult to make very specific predictions, and I
35:35
Speaker 3: mean quantitative arguments are always in some very rough bounds
35:39
Speaker 3: of possibilities. So like trying to predict the speed doesn't
35:42
Speaker 3: extinct on us, or we don't even know for sure
35:45
Speaker 3: what the bounds can be. But we can do what
35:46
Speaker 3: we'd call sensitivity analysis, or the different inputs we put
35:49
Speaker 3: into the model, So how big are the leg muscles,
35:53
Speaker 3: where are they attached to, so on and so forth,
35:56
Speaker 3: and then see what the output of the modeling analysis is, Well,
36:00
Speaker 3: how does that change running speed if we change these assumptions.
36:03
Speaker 5: In the model.
36:04
Speaker 3: Another thing we do that's really important, and this is
36:06
Speaker 3: where my training in biology really comes to bear and
36:09
Speaker 3: my work with living animals is we can apply the
36:12
Speaker 3: same methods to a model of living animals and see
36:16
Speaker 3: can we predict how a living animal works based on
36:19
Speaker 3: the same kind of modeling approach as we apply to
36:23
Speaker 3: an extinct animal. And comfortingly, when we do those kinds
36:27
Speaker 3: of tests, they usually do pretty darn well. So we
36:29
Speaker 3: can predict that a bird can run by ped lee,
36:32
Speaker 3: whereas a crocodile that doesn't run by p Lee cannot.
36:35
Speaker 2: That's very cool that you apply your mechanism to animals
36:38
Speaker 2: where you can check yourself.
36:39
Speaker 3: That's very cool, very important.
36:41
Speaker 2: But also, as a complete non expert in biology or
36:44
Speaker 2: in dinosaurs, I have the sense that our mental imagery
36:48
Speaker 2: of how dinosaurs stood and moved and looked has changed
36:52
Speaker 2: over the last fifteen hundred years. You know, like t
36:54
Speaker 2: Rex used to look more like standing up, and now
36:56
Speaker 2: we think dinosaurs might have all had feathers or something
37:00
Speaker 2: to tell us that a lot of what we're assuming,
37:02
Speaker 2: that the assumptions we're making might be changing with time
37:05
Speaker 2: and might have uncertainties we haven't accounted for.
37:07
Speaker 3: Yeah, and I think that's the great thing about science
37:10
Speaker 3: is these things can always be updated. Everything's provisional. They
37:14
Speaker 3: need to be revisited. I mean, someone might come along
37:17
Speaker 3: and show that my work that I did twenty years
37:19
Speaker 3: ago is wrong, and that's just the way it goes.
37:21
Speaker 3: The key thing, I think is to be explicit, to say,
37:24
Speaker 3: here's my set of assumptions. Here are the data that
37:26
Speaker 3: go in, here are the data that go out, here's
37:28
Speaker 3: the methods that are used. So it's all reproducible, and
37:32
Speaker 3: someone can go back and say, oh, no, I found
37:34
Speaker 3: some other information that changes that inputs completely, or changes
37:38
Speaker 3: the way we should even model the whole thing completely
37:42
Speaker 3: the way the whole system might work, and so they
37:44
Speaker 3: could repeat or do a completely new invention of that
37:48
Speaker 3: kind of analysis. I think that's the key.
37:51
Speaker 2: And sorry if I missed this earlier. But what was
37:52
Speaker 2: the thing that limits t rexes to not going much faster?
37:56
Speaker 2: Or what was the thing that we learned about t
37:58
Speaker 2: rexes that change people minds about why they couldn't go quickly?
38:02
Speaker 3: Living land animals, no matter of what their size is,
38:06
Speaker 3: can only devote so much of their body mass to
38:10
Speaker 3: muscle that supports the body weight. You have to have
38:14
Speaker 3: not only muscles, but bones, skeletons, lungs, brains, so on
38:17
Speaker 3: and so forth. And the upper limit of that muscle
38:22
Speaker 3: mass that we can see in nature appears to be ostriches.
38:27
Speaker 3: Large per fraction of ostriches is leg muscle that supports them.
38:30
Speaker 3: You think about an ostrich it's got a long, skinny neck,
38:33
Speaker 3: tiny little head, tiny little wings, no tail to speak of,
38:37
Speaker 3: a big torso, But really most of it is these big, long,
38:41
Speaker 3: meaty legs and no dinosaur was really built like that,
38:45
Speaker 3: Nothing like a t rex was built to have a
38:47
Speaker 3: body devoted to muscle like an ostrich does today. So
38:52
Speaker 3: we could use an ostriches like an upper limit for
38:54
Speaker 3: what we know of in terms of how much muscle
38:58
Speaker 3: a dinosaur might have had. Even that that would be
39:00
Speaker 3: a bit straining credulity if we did say a dinosaur
39:04
Speaker 3: had that much muscle.
39:05
Speaker 2: Are you saying an ostrich would beat any dinosaur in
39:08
Speaker 2: a foot race?
39:09
Speaker 5: Yeah?
39:10
Speaker 3: Yeah, I think it probably would. But even ostriches have
39:13
Speaker 3: more muscle devoted to their limbs than like past animals
39:16
Speaker 3: like cheetahs or big animals like rhinos or elephants do.
39:20
Speaker 3: They're super muscular animals.
39:21
Speaker 1: All right, So let's take a break, and when we
39:24
Speaker 1: get back, we're gonna hear about some weird stuff that's
39:26
Speaker 1: been in John's freezer.
39:27
Speaker 2: Oh, As someone who is married to biologist and has
39:47
Speaker 2: weird stuff in his freezer, as a result, I am
39:49
Speaker 2: terrified to learn what John might have in his freezer.
39:54
Speaker 1: Yeah. So, John, you have a really great blog called
39:57
Speaker 1: What's in John's Freezer? And I decided I shouldn't look
40:01
Speaker 1: at it with my husband around because it might turn
40:03
Speaker 1: his stomach too much. But you've had some cool stuff
40:05
Speaker 1: in your freezers. Can you tell us about some of
40:08
Speaker 1: the cool stuff that's in your freezer and what you've
40:10
Speaker 1: done with it.
40:10
Speaker 3: The glory days are gone you used to have cooler stuff,
40:14
Speaker 3: although I mean there's still some cool stuff there. I've
40:16
Speaker 3: been trying to get rid of stuff lately because it
40:18
Speaker 3: just got too full and became kind of a hazard
40:21
Speaker 3: with piles of frozen stuff getting up to the ceiling
40:24
Speaker 3: of this walking freezer. But yeah, I mean, over the years,
40:28
Speaker 3: I've had a lot of parts of elephants because elephants
40:32
Speaker 3: die in captivity, and zoos give parts of them at
40:34
Speaker 3: least to me to study for research. And then we
40:37
Speaker 3: take those parts and use them to help us understand
40:41
Speaker 3: like the anatomy of elephants and how things can go
40:43
Speaker 3: wrong in elephant feet, which are a big cause of
40:46
Speaker 3: mortality in elephants. They have a lot of problems with
40:48
Speaker 3: their feet. We can use the information from cadavers to
40:51
Speaker 3: actually contribute to taking care of animals like elephants. A
40:55
Speaker 3: lot of elephant parts, rhinos never had a hippo of drafts,
41:01
Speaker 3: lots of crocodiles of all kinds, of different species. I
41:04
Speaker 3: love crocodiles. I'm crazy about them and have done a
41:07
Speaker 3: lot of research on crocodiles.
41:09
Speaker 2: What's to love about crocodiles?
41:11
Speaker 3: Sorry, guys, Oh, they're so so bizarre.
41:16
Speaker 2: I've just shocked two biologists. Everybody out there should have
41:19
Speaker 2: seen their faces. The horror, the outrage, the surprise. Really
41:23
Speaker 2: tell me, I'm imagining crocodiles like eating dogs and like
41:27
Speaker 2: snatching babies. What's amazing about crocodiles. Why do we love them?
41:30
Speaker 3: Well, just that it means that's pretty good right there.
41:35
Speaker 2: Wow, you're coming out as anti baby on the podcast.
41:37
Speaker 2: That's amazing.
41:38
Speaker 3: Seriously. What's cool about them is that I think they've
41:42
Speaker 3: gotten the short stick in terms of being just dismissed
41:45
Speaker 3: as living fossils, which, yeah, they look a lot like
41:48
Speaker 3: they did back in the Cretaceous when dinosaurs were around.
41:51
Speaker 3: They've remained somewhat conservative over time, although there have been
41:55
Speaker 3: some groups of crocodiles that have come and gone even
41:58
Speaker 3: since the dinosaurs went that we're pretty darn weird.
42:01
Speaker 2: And just to be clear, you're not making a political
42:03
Speaker 2: statement that conservative animals eat babies.
42:06
Speaker 3: No, not yet. Yeah, So crocodiles are just bizarre. They're
42:13
Speaker 3: not some sort of primitive thing everywhere you look at them.
42:16
Speaker 3: Their body plan is incredibly specialized and modified. They're not
42:21
Speaker 3: like some pulled over from some unspecialized, imperfect body plan.
42:29
Speaker 3: They're really amazing at what they are able to do.
42:32
Speaker 3: The way they breathe is really remarkable. They have this
42:35
Speaker 3: muscle that attaches to their pelvis that pulls their liver
42:38
Speaker 3: forwards and backwards, working like a piston to pull air
42:42
Speaker 3: in and out of their body, kind of like we
42:44
Speaker 3: use our diaphragm, but with a totally different mechanism, And
42:49
Speaker 3: they can produce the largest bite forces of pretty much
42:52
Speaker 3: any animal we know of, So they have gigantic jaw
42:54
Speaker 3: muscles toward the back of their jaws that can produce
42:58
Speaker 3: lost lots of force. As I showed in some of
43:01
Speaker 3: my research, most species of crocodile can use these really
43:05
Speaker 3: extreme bounding and galloping gates that we would normally think
43:08
Speaker 3: of as mammalian like kinds of movement. So they bend
43:12
Speaker 3: their backbones up and down instead of side to side
43:15
Speaker 3: and go airborne for substantial periods of time, and can
43:18
Speaker 3: go pretty quickly overground when they're small, at least once
43:22
Speaker 3: they get big, they seem to lose that ability. But yeah,
43:25
Speaker 3: they can be pretty great athletes, and so on and
43:29
Speaker 3: so forth. Man, I could go on and on about this.
43:30
Speaker 3: I just think they're really neat and you might look
43:32
Speaker 3: at them and think, oh, that's just another lizard. Lizards
43:35
Speaker 3: are great in their own right, but a crocodile is
43:37
Speaker 3: not just an armored lizard or something like that. That's
43:40
Speaker 3: completely different. It's its own thing.
43:42
Speaker 1: I gotta say a little jealous. In my field, the
43:45
Speaker 1: calls that we get are like, oh, hey, Kelly, I
43:47
Speaker 1: saw some really fresh roadkill. Do you want to come
43:50
Speaker 1: grab it? And like the answer is always yes, because
43:52
Speaker 1: there's probably some really great parasites in there. This is
43:56
Speaker 1: a bunch of tapeworms from a road killed porcupine. I
44:00
Speaker 1: know good stuff in my office here, but I don't
44:02
Speaker 1: have anything as cool as what you've got in my freezer.
44:05
Speaker 3: Well, you can always come visit and have a tour.
44:07
Speaker 3: I'd be glad to show you around. I've got ostriches EMUs,
44:11
Speaker 3: there's a buffalo somewhere in there.
44:13
Speaker 2: I've got a very Gary Larsen image of your freezer
44:15
Speaker 2: going on right now with like you know, ostage head
44:17
Speaker 2: sticking out and giraffe limbs everywhere. Is that pretty accurate?
44:21
Speaker 3: It's kind of like a frozen Noah's arc. I guess
44:23
Speaker 3: you could say this.
44:26
Speaker 1: That's awesome. I'm going to see you in May. Okay, great, Yeah,
44:31
Speaker 1: I'm coming back to town in May. I'm going to
44:32
Speaker 1: visit your freezers. Right So, what are the big open
44:35
Speaker 1: questions in your field right now?
44:36
Speaker 5: Oh?
44:38
Speaker 3: Oh boy? Some of the ones we touched on earlier
44:40
Speaker 3: is like, what really limits size in animals? What limit
44:44
Speaker 3: speed in animals? How flexible is that? How flexible are
44:48
Speaker 3: those things? And how has that flexibility or the constraints
44:52
Speaker 3: on animals evolved over time with like changes in ecosystems,
44:56
Speaker 3: changes in animal tissues, or what have you. I think
45:00
Speaker 3: there's still a lot that we can learn about what
45:04
Speaker 3: the range of possibilities is in animals. And the goal
45:07
Speaker 3: of my work that I've been really pushing on for
45:10
Speaker 3: a long time, and I think a good general goal
45:13
Speaker 3: for paletology is that palingtology should be able to teach
45:17
Speaker 3: us things about biology and contribute to theories in biology
45:21
Speaker 3: as a whole, not just be a slave to biology
45:24
Speaker 3: where we're always looking to biology, looking to nature today
45:27
Speaker 3: to try to solve questions about the past, but contributing
45:31
Speaker 3: to broader theories about animals in general through looking at
45:36
Speaker 3: the past and the present. So like my studies of
45:39
Speaker 3: how big animals are limited by their size and how
45:43
Speaker 3: the athletic they can be, it's all about all these
45:46
Speaker 3: different groups living in extinct. I don't care if they're
45:48
Speaker 3: living or extinct. I want to know what the principles
45:50
Speaker 3: are that we can derive from them, and I want
45:53
Speaker 3: to be able to prove to colleagues, regardless of what
45:56
Speaker 3: field they're in, that I can answer those questions and
45:59
Speaker 3: that we can learn something from a t rex that
46:01
Speaker 3: isn't just you know, a variant of what we already
46:04
Speaker 3: could learn from an elephant. That's a selfish example, just
46:08
Speaker 3: explaining what I would say is big questions.
46:11
Speaker 2: Do you think there are big surprises waiting for us underground?
46:14
Speaker 2: You know? Is it possibility we could find a new
46:17
Speaker 2: huge dinosaur that blows your mind? I mean, we found
46:20
Speaker 2: like the Supersaurus and the Gigantosaurus and the Titanosaurus. Is
46:25
Speaker 2: there the possibility of some like uber Megasaurus to be
46:28
Speaker 2: discovered or do you think we've sort of maxed out
46:30
Speaker 2: the size of dinosaurs.
46:31
Speaker 3: Or a hollow earth like filled.
46:32
Speaker 2: With giants exactly.
46:37
Speaker 3: No on the latter point, A very firm no there.
46:39
Speaker 3: But in terms of finding giant dinosaurs, yeah, I mean
46:43
Speaker 3: over the last twenty thirty years, there have been larger
46:47
Speaker 3: and larger sore pods that have been found, including more
46:50
Speaker 3: and more complete ones. There's like seven skeletons of one
46:53
Speaker 3: really giant animal called protagotitan that I've worked with a
46:56
Speaker 3: small amount with colleagues on and that's one of the
46:59
Speaker 3: biggest and animals ever. It's up there as a contender.
47:02
Speaker 3: And yeah, to have sudden skeletons of that is really remarkable.
47:06
Speaker 3: But discoveries are pushing the boundaries continually. And we suspected
47:12
Speaker 3: that dinosaurs were feathered, but it wasn't until almost thirty
47:17
Speaker 3: years ago that we actually found out that many dinosaurs
47:20
Speaker 3: were from some pretty startling discoveries in China. So we
47:24
Speaker 3: know from the history of paleontology that there can be
47:27
Speaker 3: shocks there in terms of revolutions that can happen. Going
47:33
Speaker 3: up and digging fossils is always the primary lifeblood of paleontology.
47:37
Speaker 3: That's where discoveries ultimately come from. I don't do that
47:40
Speaker 3: kind of work. It's just not my skill set. I
47:42
Speaker 3: do the more lab or computer based work where I'm
47:45
Speaker 3: trying to unravel what it all means. But yeah, I'm
47:48
Speaker 3: sure there's more surprises to come.
47:50
Speaker 1: It's time for the alien question. Daniel.
47:53
Speaker 2: Well, it's always inspiring. I think for listeners to hear
47:55
Speaker 2: that there are lots of mysteries left to unravel. And
48:00
Speaker 2: mystery I think about a lot is what life might
48:02
Speaker 2: look like on another planet. And I wonder if you
48:05
Speaker 2: might speculate with us, because everything you've learned about comes
48:09
Speaker 2: from the experience here on Earth, and we don't know,
48:11
Speaker 2: of course, if this is typical, if we've explored all
48:14
Speaker 2: the effective possibilities that biology allows, or if life on
48:18
Speaker 2: Earth went down some weird little nook and most of
48:21
Speaker 2: life in the university is different. It's all weird and
48:24
Speaker 2: hollow bubbles or something. So, if we are about to
48:27
Speaker 2: land on an alien planet and you're a biologist on board,
48:30
Speaker 2: what are you expecting to see in terms of large
48:34
Speaker 2: animals on an alien planet? And you know, as an
48:37
Speaker 2: efficionado of monster movies, feel free to go weird and
48:41
Speaker 2: crazy in science fiction.
48:42
Speaker 3: What would I expect to see? I'd be surprised if
48:44
Speaker 3: there are large animals, Well, it depends on what we
48:46
Speaker 3: would know about the planet if it had been a
48:49
Speaker 3: place where the environment had been fairly stable for some time,
48:53
Speaker 3: given a long enough time for large animals to have
48:56
Speaker 3: evolved at all and not having mass extinctions screw it
49:00
Speaker 3: all up, then I might be more inclined to expect that.
49:05
Speaker 3: But anyway, all right, if I was expecting a big animal,
49:10
Speaker 3: well I'd be wondering what's supporting itself with? Are we
49:13
Speaker 3: going to learn something entirely new about supportive tissue, like
49:16
Speaker 3: is it gonna just not have anything remotely like muscle
49:20
Speaker 3: some other thing? Is it even a protein that's it's
49:23
Speaker 3: using to provide an active support or is it I
49:27
Speaker 3: don't know this boy. The boundaries that the possibilities there
49:32
Speaker 3: get so interesting, and certainly depends on whether you are
49:36
Speaker 3: a carbon based life form ultimately or silicon or whatever
49:41
Speaker 3: else they're using as their building box. And if they
49:44
Speaker 3: have DNA, what kind of DNA? Is it? Double banded,
49:47
Speaker 3: triple banded? Is it to following the same curvature as
49:51
Speaker 3: our DNA or the opposite handedness? Does that even matter?
49:56
Speaker 3: I don't know? Or are they using something totally different
49:59
Speaker 3: as heret material that would be a game changer for
50:03
Speaker 3: what evolution can even do. But I'm not sure I
50:07
Speaker 3: can give you a very satisfying answer for what I
50:10
Speaker 3: would expect in terms of animal life. It's so wide
50:15
Speaker 3: open for possibilities.
50:17
Speaker 2: That's a pretty satisfying answer, honestly, to think that it's
50:20
Speaker 2: very wide open and we could be very surprised.
50:22
Speaker 3: I'd still expect the fundamental principle of the square cube
50:26
Speaker 3: LA probably would hold if you've got a wide enough
50:29
Speaker 3: size range of animals that ultimately, if you push size
50:32
Speaker 3: to it large enough extreme on land where gravity is
50:36
Speaker 3: affecting organisms, then they're going to hit a limit and
50:39
Speaker 3: something's going to have to change. They're going to have
50:41
Speaker 3: to slow down or really change their shape or something
50:45
Speaker 3: like that. That would be a prediction that's really rooted
50:48
Speaker 3: in physics and fundamental theory of animal size and shape change.
50:53
Speaker 3: I'd feel pretty confident in that, but I don't know.
50:57
Speaker 3: Biology can screw things up, and maybe they change. There
51:00
Speaker 3: are molecules that they're made of as they go from
51:02
Speaker 3: small to big and just break the rules of what
51:04
Speaker 3: we think is normal.
51:06
Speaker 1: Leave it on a high note here for Daniel, we
51:08
Speaker 1: can be sure about the physics, but the biology can.
51:10
Speaker 2: Screw things up all right, As usual with biology, it.
51:14
Speaker 1: Depends its Yeah, so that's the rule in ecology at least.
51:19
Speaker 5: All right.
51:19
Speaker 1: Well, John, thank you so much for being on the show.
51:22
Speaker 1: That was a ton of fun and I really hope
51:24
Speaker 1: I get to check out your freezer one day.
51:26
Speaker 3: Please do a comment. Yes, it's an open invitation for
51:28
Speaker 3: you both.
51:29
Speaker 2: John ever serves you dinner, you should ask what's innsburger?
51:36
Speaker 2: Or don't ask?
51:38
Speaker 1: Yeah, I think don't ask is the way to go.
51:39
Speaker 3: You can ask, I won't be offunded.
51:49
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51:55
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52:07
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52:23
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