Dr. Chris J. Law

My name is Chris Law and I go by he, him.

Yes.

Dr. Chris Law.

Yeah.

So I essentially started my science career with polychaete worms during my undergrad at UC San Diego.

And then as I was applying grad school, I met with my future PhD advisor, Rita Meda at UC Santa Cruz.

And we're just chatting about potential research projects.

And she studies moray eels.

So I was just assuming I was going to be working on some fish project, which is fine because my plan is just to go up the food chain.

But then we were just chatting a little bit and she just brought up the idea, why don't you just work on sea otters?

Because we're in Santa Cruz and they're just all over the place.

And obviously I was like, yeah, of course.

I've seen them before, and they're adorable little teddy bears that you just want to hug, and who doesn't want to work on them?

So the moment she said that, I kind of just jumped on that bandwagon and started doing some research into what potential projects I could do.

And since they eat all these hard shell parietums,

one of the questions we really wanted to look at is just how are they actually breaking into those hard items?

So kind of just got started on that.

So basically, in undergrad, I come from like a phylogenetics background and evolutionary background.

So I'm kind of halfway through working with sea otters or starting to look into sea otters, I just got this idea, I have to build a phylogenetic tree of all of the

Not only otters, but the weasels, marns, wolverine, all those guys.

So I just started building that phylogenetic tree and then just learning a bunch of natural history by reading about this group.

I at first didn't even know that weasels were related to otters.

So I learned more about weasels and kind of went down this rabbit hole to want to study why they so elongate.

The idea is that it came around 15 or so million years ago.

That's during the mid-Masin climate transition when temperatures drastically decreased and this expansion of grasslands occurred, which then led to the diversification of rodents.

So then this body elongation is hypothesized to have allowed those weasel-like creatures to go underground to chase all those rodents in these tight crevices and whatnot.

Yeah.

So that's the idea behind their kind of artificial selection, right?

Where people really are trying to breed these elongate looking dogs so they can go in these tight crevices or burrows to try to get those rodents during hunting.

That is a fascinating question.

So if you think of snakes or eels, they become more elongate by just simply adding more vertebrae, which makes sense, right?

But then with mammals, we're actually constrained to the number of vertebrae that we have.

So

In carnivorans, which are like dogs, bears, cats, they have about 20 thoracic lumbar vertebrae, and that number rarely, rarely changes.

So it can't become elongate by just adding additional vertebrae.

They have to actually evolve relatively longer vertebrae.

Yeah, exactly.

So they have the exact same number of vertebrae.

It's just some of the breeds might have relatively longer ones, although no one I don't think anybody has really looked into that.

So it'd be really interesting to see the skeletal elements of what actually contributes to those different body plans in these different breeds.

Yeah, so it's in the order carnivora.

And carnivora is split into two different main groups, the filiformes, which are like your cats.

And then the other group are the caniformes, which are your dogs, bears, pinnipeds, and the mustelids, which are the raccoons, weasels, skunks, otters, all those guys.

So basically, in the caniformes, it goes...

Dogs, bears, pinnipeds, then skunks, the red panda, raccoons, and then the mustelids, which includes that really species-rich group that includes the otters, the weasels, the wolverine, the martens, the honey badger, the European badger.

There's like over 60 species in mustelidae.

Yeah, I mean, that's why I love learning how to make phylogenetic trees.

I think it's just such a cool way to just showcase the evolutionary history of basically the tree of life.

And with the carnivorans in general, it's such a diverse group and so many different types of body plans and different sizes and shapes.

So it's really cool to be able to visualize all that and how this one species evolved

came from this group of species or how these two closely related species are from the same part of tree, but then look so very different.

So yeah, that's part of the fun parts of being an evolutionary biologist.

I pretend to be.

It comes and goes.

Oh, I mean, I wish I could do all of that.

The closest I've done is touched one.

It is honestly the softest thing, at least the sea otter, it's the softest thing I've ever felt.

I totally understood or understand why people back in the day really wanted to hunt them just because

that pelt, like you just want to rub your face on them because it's just so soft.

And I'm sure it's also pretty warm in terms of doing all the other stuff in terms of like wanting to hold their hands.

I don't think I would ever want to do that with the wild otter because they will try to eat your face or like bite your face if they could.

They're pure evil.

Oh, I mean, yeah.

So basically everything you said is true.

Probably the worst thing is that they can also be dog killers.

So apparently there were a couple incidents where somebody's dog was just like barking at one of these otters along like the dock or something.

And I guess that otter just got fed up, went up to it and just apparently dragged it down.

And I believe it might have drowned it, but...

Again, this is just through word of mouth, so who knows?

I've heard this a couple of times and this has happened a couple of times.

So it's kind of gnarly.

Oh, so actually a sea otter is much bigger than a North American river otter.

But in California, they don't get that big.

Those are more Alaskan otters.

But they are still much bigger than a little river otter.

Definitely can be pretty vicious if you get too close to them.

Yeah, so actually all other otters are primarily freshwater.

So it's the sea otter that's unique.

It's that oddball that evolved from all the other otters like about 8 to 10 million years ago.

And it went on basically its own evolutionary trajectory.

So everything it does, everything about their...

physiology is very different compared to other river otters.

And sea otters are primarily just found in the ocean, whereas river otters, especially like North American river otters and Eurasian otters will actually go into the marine environment as well.

So you can find, you can be in locations like in Washington where there will be both river otters and sea otters.

Sea otters?

Yeah, so river otters have dens that they hang out.

I've never actually seen one, but yeah, presumably along the shore.

But then sea otters actually just float in the water.

And I'm sure you've heard stories of where they can wrap themselves in some kelp so they don't float away and they can take a nap that way.

They're relatively small marine mammals.

They burn a lot of heat, so they have to sleep a lot to refuel.

And you always see them just taking a snooze to conserve some energy.

So I don't I actually don't know, because I remember giving a presentation at this, I think, sea otter conference.

And I had an image of that, you know, that image of two sea otters holding hands that was taken at one of the aquariums.

Somebody gave me shit for it without doing that because she said that they don't hold hands in the wild.

But then apparently a couple weeks or months later, there's like some photos of wild otters holding hands.

So I don't know.

Oh, yeah, there's a huge effort out all the major aquariums.

So like the Monterey Bay Aquarium in California, the Seattle Aquarium in Washington, I'm sure up in BC and Alaska also has great efforts.

But the one I'm most familiar with are the ones down in Central Coast, California, where the Monterey Bay Aquarium, UC Santa Cruz.

the U.S.

Geological Survey, Fish and Wildlife, basically all of these organizations, they do all of this great outreach work and also a lot of work with the wild populations to make sure that the population is doing well, that individuals are healthy, and that, you know, all the possible things that could affect them are looked into.

Yeah.

So I guess it's very different depending on what population of sea otters you're talking about.

So that kelp to urchin to sea otter system is really describing the Alaskan populations pretty well.

So that classic killer whale is eating the sea otters, which then increases urchins to

which then decreases kelp forest.

But then in California, the system's a little bit different.

Where the sea otter population is actually doing relatively stable.

So I think there's about maybe 3,000 individuals in coastal California.

I could be wrong on that.

I have to check my numbers.

But basically, the idea is that they are kind of constrained between Point Conception down south and Half Moon Bay up north.

And the reason why they can't expand is because they're being attacked by sharks up north.

And I guess fishermen are pushing them back up from the south, so they can't really expand.

And that way, they're more like this carrying capacity where

They're running out of food and the otter population can't really increase because of that.

It basically is very, um, it's basically just.

Yeah.

Yeah.

Otters.

So females have it rough because basically the moment they become sexually mature, they are either pregnant or have a baby with them or a pup with them until they literally exhaust themselves to death.

And it's called end lactation syndrome for the females where they just basically just die because they're just so exhausted from lactation.

You know, putting so much energy towards their pups or towards milk production.

And they also have to afford for their pups.

And I'll say one thing.

Some of those pups are basically just like little parasites.

I remember just watching a mom and a pup interact.

And this pup is almost bigger than the mom.

And it was still hanging out with mom.

And the moment mom goes diving, the pup just like hangs out on the surface being all cute and happy.

But then when the mom comes up with food, it just immediately swims to the mom and just starts like, you know, crying and begging for food.

And again, this pup is almost bigger than a mom.

Basically, pups usually stay with the mom for six months to up to a year.

And it's usually those slackers that are staying up for a year are usually just as big as the mom, still continually getting food from it.

Uh, so, so yeah, the evolution question, um, I think it's just because that pup will be like nice and fat and ready to kind of go hunt on its own because if it gets weaned too early or it leaves mom too early, it's not going to be able to eat or get enough food and it's just going to die.

And in that case, you're just going to lose your, you know, offspring and your genetic potential, right?

If that happens.

So evolutionarily, you know, there might be that reason for why, uh,

why that pup really wants to extract all the nutrients from the mom before it can go off on its own and do its thing.

Yeah.

And in terms of the males, oh, yeah, those guys don't do anything.

Basically, the males are constantly circling females because once that pup leaves, it's going to go, you know, reproduce to pass off its genes.

And then once that happens, I mean, it's a terrifying show that, I mean, I'm happy to describe it.

So normally once that female is free, the male would get on it and it's essentially where the male will bite onto the female's nose.

So often you'll see females with ripped noses and you can easily tell that's a female just because it's biting down on that nose and basically forcing itself on it to pass its genes.

So once that happens, the male just leaves and you'll probably never see the female ever again.

I don't think so.

And yeah, and also the females are much smaller than than the males.

So they're kind of defenseless in that regard.

I know.

If only they could.

Like I said, basically, that's the theme of life.

And they do this for maybe like 12, 15 years at the most in the wild where basically they just get pregnant a couple of times.

Or like a lot of times during their lifetime and just reproduce and have pups and cycle just continues over and over again until they die from exhaustion.

It's pretty nuts.

No.

So usually in captivity, all the otters that you might see in aquariums are all females because a lot of these bigger aquariums, they actually use them as surrogates for wild otters that might be orphans.

So if the mom in the wild dies, there's usually this pup that's wandering alone.

And since they're threatened, at least in California, there's been a program to basically take these otters in and especially their females, they'll have the surrogates raise them until they can re-release them in the wild when they're old enough.

That's usually unique to captivity.

I don't think I've ever heard any situation where a wild female would take in another stray pup.

And usually if the stray pup is alone, it's not going to even survive for that long because it's basically defenseless and hopeless.

It can't even go catch its own food by itself.

So it'll just die.

Yeah.

So yeah, that's why, you know, like the O'Hanrae Bear Aquarium really relies on stranding networks or like volunteers or people just, you know, observing or seeing a wild otter bites or like a little pup that somebody will call it in and they'll send out a team to bring it in if they can't locate their mom or something like that.

That's a great question.

I don't know why they are so cute, but how it's because their skulls are very flat faces.

So if you look at a basically a newborn CR skull, it doesn't have that snout pronounced snout yet.

So it's very like a puppy dog face or like even like a newborn baby's face.

And which I guess, in our brains is hardwired to, you know, want to like, take it and hold it and protect it and all that.

But in terms of why they might be like that in the wild, I have no idea what kind of selective advantage that is.

Maybe other animals think it's cute, or maybe other otter individuals might have some kind of selective pressure on it, but I have no idea.

Yeah.

Yep.

Sounds great.

Yeah.

So otters don't eat the kelp.

They just live in it.

So they'll use it and wrap themselves in it to stay in one place if they're sleeping.

But they really rely on it indirectly just because it's such an important ecosystem in California where all their basically invertebrate prey that they're eating live off it or live under it or live on it.

So it is really essential to them indirectly.

Exactly.

Yeah.

And they rarely leave it just because it's a nice protected area.

So it's harder for predators to find them.

Yep, they essentially eat your favorite types of seafood.

So you got your snails, your clams, your mussels, your abalone, your crabs and urchins.

They also eat these kind of gross looking things called fat innkeeper worms.

I don't know if you've ever seen pictures of them.

Yeah.

So they'll eat those as well.

But most of their prey are usually hard shell prey because they contain more calories.

So that is a myth.

They do not have a favorite rock.

No.

So often these rocks are pretty big and they do have like a little, I guess you could call it a pocket, but it's just a flap of skin that they can keep prey in.

But these rocks are usually too big to do that.

So normally what they do is they come up with a rock and they're prey.

They put the rock on their belly, use it as an anvil and break things, eat the things.

And they keep doing that.

And basically when they're done with the rock, they just do a little turn.

The rock falls down and then they go on with their lives.

So they don't really have that favorite rock.

I mean, they might reuse the rock if it's the only rock that's available because they are just right there and just decided to go back down and get more food.

And that rock happens to be there.

So they might pick it up again to use it.

But they're definitely not traveling around with it.

Yeah.

I mean, no, we call it, we still call it as a tool use because it is still, you know, you're still putting an object onto your, you know, stomach and then actually using it as a, as a tool essentially to break something open.

And I'll say that otters can also use other objects as tools.

So sometimes they'll use another shell to break open in their shell.

They'll use like bottles.

They'll even use like docks and people's boats to break things open.

So they'll use anything.

I don't know how common it is, but it definitely is to a point where there's multiple observations of them doing that.

So the way males' territories work is that the dominant males have territories that exclude other males from their territories, right?

And in that kind of competition, there's always going to be losers, and they're excluded from these territories.

So if they can't have their own territory to mate with females, they just get, I guess, frustrated and find that a little baby seal to do it's, you know, to basically it, I guess.

And that's usually doesn't end well with the seal.

One thing that's crazy about these male-to-male conflicts is that when they fight each other, they essentially go after each other's baculums, which in carnivorans, carnivorans have a bone called a baculum in their penis.

So they go after each other's baculum to try to break it.

So it's pretty brutal out there.

Honestly, I have no idea how that compares to other mammals groups.

One of the nice things about sea otters is that they have to come to the surface and they just float.

So it's just so easy to get these observations because they're also really close to shore.

So like we were able to get these detailed information, whereas like other smaller animals, like even river otters, it's really hard to spot them and actually see what they're doing in the wild.

So who knows what they're doing out there?

Weird, wacky stuff.

Oh, there you go.

So there's these things called giant river otters in South America and the Amazon.

And these things are a little bit longer than the sea otters.

And if you ever see pictures of these ones, they are so weird looking.

They are another older lineage of otters that kind of offshoot from other otters like 10 million years ago or so.

But they got really like buggy eyes and they got their faces just like an alien otter.

But these guys are huge and they actually are in family units and they will actually go sometimes go after like caimans.

And there are even reports of them like fighting off jaguars.

Which is pretty crazy.

But yeah, the advantage for those guys is that they are in a group setting.

So they have kind of each other's back to try to, you know, fight off predators that might try to attack their young.

I will have my vengeance.

The cutest thing I've ever seen is probably just like a little baby sea otter pup that's just floating by itself waiting for its mom.

I mean, I know I told you about how just waiting for mom to bring up dinner, essentially.

But before that, it's just floating by itself like a little cork, closed eyes, all fluffy and like just...

Look at me.

I'm so adorable.

Like it's got like 10 photographers just around like along the coast or coast trying to take up its picture, including me.

Like it's adorable.

Probably the most playful time I've seen otters are actually river otters.

They actually play.

So like they will swim next to each other or like go up and down or just run all over the place.

So I've seen that in river otters, but I've never really seen that in sea otters.

Yeah, so sea otters have the densest fur, I think, of all mammals.

So basically, sea otters have no fat on them whatsoever, so they're really reliant on that dense fur.

And it does keep them warm, super warm.

So that's why they're able to tolerate living in all these freezing, frigid environments just fine.

And I would imagine river otters also have similarly dense fur.

So that's why they're able to live in Scotland and all these other cold places and play in the snow.

I definitely have never heard otter poop being described as violet.

I have never smelled otter poop, but I would imagine it smells like the worst shit you could ever smell because they're eating seafood, like raw seafood, and that doesn't smell good.

So I don't think I ever want to smell it, but I've never smelled it, but I would imagine it's probably the worst thing you could smell.

Yeah.

Yeah, so I've done that a couple of times.

I was primarily trying to film their tool-using behavior so we could try to quantify the kinematics behind it.

So I mean, I call it, it's not really, I mean, I guess you could technically call it field work, but it's basically you go to the beach and you just have a little camping chair, set up the camera and just hang out there until you see an otter that's close enough to start filming or take photos of it.

And like, it's California.

So it's like what, a nice 70 degree sunny day,

can't complain.

Yeah.

So it's not, yeah.

Yeah.

It's obviously very rough field work.

No, I usually go with the chocolate croissant.

It makes sense.

Okay, well then good.

It's called that now.

Yeah, if we all just start using that, it'll eventually catch on, I think.

No, they're definitely waterproof.

They can get wet.

The reason why the mom is trying to dry it out, it's just to conserve heat.

It's also cleaning the fur.

So otters spend like a third of their life just cleaning, grooming.

Because they rely on that fur as that insulation, they have to make sure that it's clean from all that dirt or debris or whatever to make sure it's actually functioning so that fur doesn't clump up and expose its skin to the cold environment.

So they really, really want to

get those pups nice and clean.

And usually it also happened to dry them out.

Right.

Okay.

Oh no.

Yeah.

Sea otters, sea otters are born to be in the water.

So,

But don't quote me on that.

What river otters do a lot, though, is that they'll mark territory.

So they'll basically leave scent marks all over the place.

And they might go to the same location all the time just to make sure that that's, you know, the boundary of their territory.

So maybe that is related to that.

So otters, or at least sea otter teeth, look very similar to ours.

At least their molars.

It's nice and big and flat.

Perfect just to crunch things.

So often if you go to where sea otters are and you're really quiet, you can actually hear them crunching.

crunching on that hard shell.

And it's actually pretty amazing.

And what's super cool about those, uh, the CR adaptations that is that they're enamel on their molars are actually fracture resistant.

So they've evolved to basically be able to sustain all of that, all that fracture forces from the prey they're eating.

Cause if you imagine, if you were trying to eat through clam shells, your teeth would get destroyed instantly.

Yeah.

So I don't know about that, but there are definitely people that have looked at the material properties of those teeth.

And I don't remember exactly what the kind of minerals they have, but they've done comparisons with like ancient humans that had much bigger jaws and bigger molars to crush those types of seeds as well.

And it's very similar there.

morphologies, and it's pretty, pretty impressive.

So it's like kind of through convergent evolution that this type of molars have have evolved to be a perfect teeth to crush things.

Um, there's just so many things to learn about them.

There's not enough time.

Um, so like we know so much about sea otters or relatively just because they're easier to study.

Um, but in terms of the other otters, especially the ones that are,

like in Asia or South America, those ones are much harder to study just because of their locations and because their population sizes are either shrinking or we have no idea.

There's actually another otter species down in South America called the marine otter.

And it looks like a river otter, but it actually lives in a marine environment too.

And it actually eats a lot of hard shell prey too.

But we have barely any idea of like what exactly it's doing, what its population sizes is.

It might not be doing well just because there's not a lot of work done on them and just in these remote locations.

There's just such interesting animals.

The fact that they have this integration between their tool-using behavior, their morphology is just unique compared to other things.

It's just interesting that they are able to gain access to these harder prey.

One thing I didn't touch on is that in Monterey Bay, these otters actually exhibit dietary specialization.

Some otters will only eat urchins, others will only eat clams, others will only eat crabs and so on.

So part of my research now is actually trying to investigate why that is or how they're actually able to eat these different types of prey.

So how is it relating to the tool using behavior and how is it relating back to their variation in their biting ability?

So as in, are some otters just able to generate larger bite forces than other otters?

So that's the type of questions that we're hoping to be able to answer soon.

Yeah, so right now that's, I think, primarily found just in California, and it goes back to that carrying capacity.

So because that population is limited in terms of resources and food,

Instead of each individual being a journalist, basically eat everything they can get, they just become super specialized and just become really good at eating a particular prey.

So one individual will just become a really good urchin specialist.

And with an urchin specialist, there's a certain way you have to extract them, a certain way you have to open them and eat them, versus an abalone specialist, which uses completely different behaviors in order to get the abalone prey.

and and eat it.

So they just become these really highly specialized individuals that really are able to get access to these different prey items and do it so well that and efficiently.

And that's just the way that they can increase that caloric income versus just becoming just a journalist and eat everything they see.

Yeah, I mean, yeah, once you know how to do it, just go for it, right?

Why learn something new?

Well, that's the thing with these otters that, you know, they're flipper tags, so people can actually ID them.

And usually the Monterey Bay Aquarium has lots of volunteers that go out to observe these otters on a daily basis.

So they're basically, if you're out there, they would be tracking.

How many eggs did you use?

How did you put any salt?

Did you use a fork?

How did you cook your eggs?

So essentially, they're basically tracking all of that information.

So they're tracking how many prey items they're eating, what kind of prey items, and estimated size of those prey items, where they use tools for that prey item.

It's pretty nuts.

Wow.

It's pretty amazing data.

I mean, who doesn't want to spend a nice morning hanging out by the coast and watching some sea otters eat their dinner or eat their breakfast?

I mean...

I mean, yeah, the otters could totally be just watching me back.

Yeah, thanks for definitely having me on.