Quirks and Quarks - How corals tell us climate change is supersizing El Niño

Episode Date: September 25, 2026

The El Niño underway in the Pacific Ocean is a natural climate phenomenon but its warming effects are being boosted by climate change. Researchers recently used corals growing around the Galapagos Islands to create a local temperature record of the ocean going back 1,000 years.Also today: Massive study redraws bat family tree and uncovers genetic odditiesHow the Surinam toad uses star-shaped fingertip lobes to ‘see’ its preyT. rex tooth enamel reveals these dinosaurs were warm-bloodedWhy great white sharks are converging on the East Coast

This week on two blocks from the White House. Donald Trump is busy with international diplomacy this week from China to the U.N. But he doesn't have too many friends in other countries these days. So we're asking, is Donald Trump even interested in having allies? Find and follow two blocks from the White House wherever you get your podcasts. And watch us on YouTube. New episodes drop every Wednesday. This is a CBC podcast. Hi, I'm Bob McDonald.

Welcome to Quarks and Quarks. On this week's show, coral reefs in the Galapagos Islands reveal how climate change is supersizing El Nino. What we found is that the strong El Ninos of the last 40 to 50 years are really unusual. We don't see anything like that in the pre-industrial era in our coral data.

And a flat, tongueless, and nearly blind toad with super-sensitive fingers and an unusual way of hunting. You would see them in a, kind of a funny posture, almost like the goalposts of an American football stadium. Plus, rewriting bat origins, a warm-blooded T-Rex, and great white sharks gathering on the East Coast. All this today on Quarks and Quarks. When it comes to mammals, bats are a bit of an oddball.

They're the only mammals that can fly for long periods of time, and they're often faster and more agile flyers than birds, capable of reach. speeds of over 150 kilometers per hour. They can echolocate, like dolphins and shrews, but they do it through the air as they fly, which is an impressive feat. And they also live a long time, defying the basic rule of biology that says that small animals have short lives. So even though bats have a bit of a bad reputation in some parts of the world, they are fascinating creatures for scientists to study, which is why a group of 137 scientists in 64 countries launched Bat 1K, an initiative to sequence the genomes of all living bat species to understand more about these unusual adaptations.

This week they released Phase 1 of this undertaking, which is in itself the largest bat genome and fossil study ever published. Canadian biologist Dr. Burton Lim is part of the Bat 1K team. he's the assistant curator of mammals at the Royal Ontario Museum in Toronto. Hello and welcome to our program. Hello and thank you very much. First of all, what was your role in this Bat 1K project? Well, I have been doing field work around the world for over 30 years, and the ROM was the single largest contributor of tissue samples

for the Bat 1K study that we just published. Well, how did you get so many bat genomes? samples? I had been doing, on average, about two to three field trips per year over that 35 plus year history. So I think I've lost track, but I think I've done about 100 field trips over the years. Wow. Where do you get your samples? Most of the places I go to are in tropical countries because a bass, like most other organisms, most of the species are found close to the equator. How do you preserve them when you're out in the field in the tropics when it's so hot? Yeah, well, we bring in the best thing possible.

We lug around a liquid nitrogen tank. And it's a bit of work. A lot of times it's hard to find liquid nitrogen in a lot of these remote places. We have to carry them in by boat, sometimes by walking, sometimes on elephants. So it's a little bit of work to get liquid nitrogen into the field. but it instantaneously freezes tissue samples at minus 196 degrees Celsius, so it's snap freezing. Wow. What's the meaning behind the term bat 1K? Well, originally when it started 10 years ago, there was only like 1,100 or 1,200 species of bats.

So now it's crept over 1,500 so. So maybe we might have to change the name to bat, 2K. So how many species does the bat 1K team now have and how many more do you need to get? Well, at this point, it is phase one, as you mentioned. So we wanted to get at least one species from each of the 21 families of bats. So we actually had 103 genomes that were done. So phase two, we'll be looking at the genera. So I think there is about, I think about 400 genera of bats. Oh, wow. So you still have a waste to go then. Yeah, that will be a big jump to the genus level. Well, what have your colleagues been finding out about the bats in this project so far?

One of the things we wanted to look at was how were they related to each other because there was a little bit of controversy over how some of the major lineages. There's five main groups of bats. So the reason we wanted to find out how they were related to each other, because that allows us to look at the origins of the bats. So looking at biogeography, so where did bats arise from in the world? And what did you find? Well, we came to the inclusion that it was Europe where the bats originated. Before that being that those five main super families of bats, I think the issue was that they had,

evolved relatively quickly sometime between 55 million years ago and 65 million years ago in that the previous techniques wasn't able to resolve exactly how they were related to each other. But when we sequenced the whole 2 billion base pair genome, we just got a more robust analysis to look at how they were related to each other. Well, 55 or 65 million years ago, that's the end of the dinosaurs. after the big asteroid hit or around that time. So what's the significance of that and that they originated in Europe? Yes, well, a lot of different groups of mammals also evolved at that time.

You know, carnivores, looking at hoofed animals, the rodents, they all sort of exploded, if you will, after the dinosaur disappeared. So basically, there are all these ecological niches that were now available. and then a lot of these groups of mammals, that's when they really started to speciate. Well, how similar were these early bats compared to the bats that we see today? Well, the interesting thing is that the oldest bat fossil is about 55 million years old, but it's no mistake in that it's a bat. It has a fully formed wing.

So we know that 55 million years ago, there were bats that flew. So the question was, you know, how far back did they go? So that's when we use the molecular data to actually go back in time to find out when the ancestral bat would have arose. So we pushed back the origins of bats back to 65 million years ago, even though we don't have fossils. But that's where the molecular data came in. Wow, they've been around a long time. What about echolocation? Do you have any idea when that appears?

Well, that was another thing that we looked at. So again, that was combining the genomic data and the morphological data. So we think that the echolocation actually rose almost hand in hand with flight. So again, 65 million years ago, when the dinosaur disappeared, that ancestral bat, that ended up speciating into over 1,500 species of bats. Wow. So what other types of discoveries are you hoping will come out of this project? Well, another thing that we've learned is that bats have a lot of diseases, a lot of pathogens. So we wanted to find out, you know, how is the bat immune system different from other animals, including humans. One of our studies from last year found out that, so humans typically tried to resist a lot of diseases, like inflammation, is the main way they combat, you know, foreign bodies that enter their system. Whereas bats, they have a little bit of inflammation at the beginning, but then they have other genes that sort of stop it. So bats actually tolerate a lot of pathogens. So just a different approach

to sort of battling sickness. So instead of resisting like humans do, bats actually just tolerate. So bats have a lot of pathogens that they just live with. Wow. So they can get a disease, but they don't get sick? Yeah, in general. Yep. Now, aren't we, though, hearing about some bats that are being wiped out by white nose syndrome that we hear about here in North America? Yeah, so that's another interesting, I guess, story. But the thing is that it's actually not the fungus that kills the bat directly, that the fungus actually alters the behavior of hibernating bats. Basically, the fungus irritates the bat. It gets on their skin.

It's almost like a bad itch. So the bats are actually, instead of hybridating in the wintertime, they're actually up in a way. and sometimes flying around because they're just irritated, you know, by this fungus. So basically, the bats end up starving before springtime, before the food comes back. Wow. Well, if this is phase one of this bat 1K project, what are you expecting to get from phase two? So I think we'll be able to, you know, mine a little bit deeper into not only how they evolved, but a lot of their adaptations because bats, they're not typical mammals. Yeah, so they do a lot

of stuff that other mammals don't, you know, as we've mentioned, they fly, most of them echolocate, you know, they're long-lived, they have a lot of pathogens, but they seem healthy. They're amazing because they do a lot of this stuff that, you know, you wouldn't think that they should be doing, but they do. So now, hopefully we'll be able to get a better idea of. of why they're doing a lot of the stuff or how they evolved to be so successful. Dr. Lim, thank you so much for your time. Okay, thank you. Dr. Burton Lim is the assistant curator of mammals at the Royal Ontario Museum in Toronto.

The developing El Nino climate phenomenon is now the strongest on record, according to scientists monitoring Pacific Ocean temperatures. This El Nino is set to be the strong. strongest in records dating back 150 years, and the Met Office says its impact are already being felt. The latest projections for this year's El Nino are being called Nothing Short of Extraordinary. Climate scientists are forecasting the worst El Nino in recorded history that could peak near four degrees Celsius above normal this November. El Nino's are a naturally occurring phenomena that heat the waters of the eastern Pacific Ocean and impact.

global weather patterns. Many sectors will be affected. Agriculture, trade, fisheries, health, energy, transport, water resources, disaster management, to name but a few. It is a risk multiplier and we expect to see health impacts across the world. A new report looks at how many deaths it could cause on top of what's already expected with some of the biggest impacts projected in global south countries already in their hot season. From the start in June of this year through February, we expect 451,000 deaths just from heat. UN Secretary General Antonio Guterres stated that the science leaves no doubt.

Climate change has put us into hot uncharted waters that's supersizing the El Nino before our eyes. I've been tracking El Nino for years, but these numbers, they're off the chart. I've never seen an El Nino this strong hit on top of an ocean that is hotter than we've ever seen it. Teasing apart how climate change is factoring into the intensifying El Nino's we've been seeing isn't easy. But one way we do that is with handy marine record keepers in the form of corals. Dr. Julia Cole led a study that was recently published in science where she used corals to look back at El Nino's over the past thousand years. She's a paleo-climatologist at the University of Michigan in Ann Arbor.

Hello, and welcome to our show. Hello, thanks so much for having me. How much of a surprise is it to you that we may be facing the worst El Nino on record this year? Well, you know, I'm not hugely surprised because our data suggests that strong El Ninos have become more the norm now than they were in the past. So while every really strong event is a little bit of a surprise, I think this is something where, it's consistent with the idea that El Nino's are getting stronger in a warmer world. Now, before you started looking at corals to go back in time, how accurate is our record of El Ninos?

Yeah, that's a great question. El Nino's happened in a really remote part of the tropical Pacific. And so right now we have satellite data that gives us a really clear picture of what's going on across that whole area. But before about the early 1980s, we didn't have that. And so our picture gets blurryer the further back in time we go. So our data on El Nino are pretty good back to about 1950, and then they just get blurrier and bluerier as you go back earlier than that.

Well, just give me a little background to hear. What exactly are El Nino's and what causes them to form and oscillate between warm and cold, like we see? Sure. El Nino refers to the tendency of the eastern and central tropical Pacific to be a little bit warmer than usual, and it has a counterpart, La Nina, in which that region is cooler than usual. We go back and forth between Elinio and La Nina naturally every few years. What happens is during what you might think of as normal conditions, the trade winds blow from east, from South America side, to the Western Pacific, the Australian side.

And as they do that, they push warm water across the equator. It gets warmer and warmer under the hot equatorial sun. That water also piles up in the Western Pacific, forming an actual hill or slope of water that's higher in the west than the east. So when those trade winds fluctuate as they naturally do, that slope can become unstable. And when they weaken, the slope can actually relax down and slosh that water or spread that warmth back towards the eastern and central Pacific. That's what happens when an El Mino develops. Wow.

It sounds like water sloshing back and forth in a bathtub. It's going from one side of the Pacific to the other. It's a little more complicated. Yeah, but that's the idea. Boy. So how does this shift in the warm? warm water affect different regions around the Pacific? Yeah, if it only happened in the remote tropical Pacific, we might not know very much about this.

But because that warm water changes how the atmosphere circulates, it turns out that El Nino's and their counterpart L'Aninios are the biggest source of year-to-year climate variability on the planet. The main thing that happens is when that warm water moves to the central and eastern Pacific, it also moves with it the pattern of atmospheric circulation across the Pacific. Overwarm water, air tends to rise because the water heats the air, the air is warm, it's lighter, and it rises up. Rising air leads to rainfall. Rising air also pulls the trade winds in from both sides, so it kind of keeps those trade winds kind of weak and disorganized

across the Pacific. And the rising air stirs up the upper atmosphere circulation, as well and shifts the pattern of atmospheric circulation around the Pacific and indeed around the entire tropics. We even see its impact on the jet stream, which is the storm track that brings storms into North America. Well, how did you use corals to help tease apart the role that climate change plays in the development of these powerful El Nino's? Yeah, we're really lucky that corals, as they grow, they record the conditions under which they grow in the chemistry of their skeletons. So a coral can live for decades to centuries, and it grows a centimeter or two every year. We take a core from those corals, and we sample that core at millimeter resolution. So that gives us

a sample every month, essentially. We're able to measure the chemistry of those samples, and we measure them with an eye towards a couple of particular compounds that are sensitive to the temperature of the formation of the skeleton. And so we're able to come, up with monthly records of temperature from these coral skeletons. And we put those together using corals that are living and corals that are dead, but we have collected on the beaches of Galapagos and we date them, they date across the last millennium. So we've put these records together for many different corals to come up with a history of

Almenio across the last millennium. Where did the corals for this current study come from? This study focused on corals from the Galapagos Islands. The Galapagos lie on the equator, about 1,000 kilometers offshore South America. And this part of the Eastern Pacific is where the biggest, strongest El Nino events have their biggest impact on ocean temperatures. So this is a really great place to study the history of the eastern Pacific side of El Nino. So you mentioned that you also study coral fossils. So what's the difference between what you get from living fossils and ancient ones?

Yeah, the living corals allow us to determine that our coral thermometer is working, basically. We can take a core from a coral that is living today, and we can take our monthly samples back through time and compare the chemistry that we get from those samples with temperatures that have been measured, either by satellites or by local thermometers. So we can ground-truth our records and confirm that the record we're getting from the corals is an accurate reconstruction of local temperature and of the broader-scale El Nino pattern. So then we can look for corals that are dead and older, and we date these using uranium-thorium-thorium methods,

radiometric dating methods, that give us ages that are accurate to within about a few years. So we might find a coral washed up on a beach that we can date to, say, 500 years ago, but it may preserve a record of 40 or 50 or 80 or 100 years in it. And so we can then do our monthly reconstruction of temperature and see what El Nino was doing at that time 500 years ago. Wow, that's amazing.

You know, you say that the Galapagos Islands are the most impacted by El Nino. You're lucky you were able to get living corals there at all because we hear about so much bleaching going on. Yeah, absolutely. In fact, my first experience in the Galapagos in 1989 was kind of a bust. You know, we went looking for corals that people had identified as living there prior to the 82, 83 El Nino event, but when we looked for them in 1989,

they weren't there, they were gone. So we really struggled to find living corals initially. But eventually we were able to work on a reef in the far northern archipelago that hadn't been well documented early before the 2000s. And we started working there and found some living corals that had managed to persist. Wow.

So what did you see once you put it all together? Yeah, we put together a history of El Niño and La Nina variability going back almost a thousand years. Our record has almost half of those years covered. We're using individual corals, so they're not continuous, but we're getting these windows on the past. And what we found is that the strong El Niños of the last 40 to 50 years are really unusual. We don't see anything like that in the pre-industrial era in our coral data. The strengthening of the variability in the Galapagos happens in in parallel with warming temperatures.

And so our interpretation is that the warming of climate is what has generated these stronger events. And we looked hard for natural explanations that could have accounted for this strengthening. But we saw no evidence that natural variability could create this same level of variability that we saw in the last 40 to 50 years. So are you saying human-made climate change is responsible?

We understand that very well that the human burning of fossil fuels is what's responsible for the warming that we're seeing today. Okay, so now that you have a better understanding of how the past climate worked and how the corals were affected, what can we expect going forward, including this year's El Nino? Yeah, that's a great question. And I have to be a little careful here because our corals provide us a window onto the past, but they don't give us a crystal ball into the future. So what we used to look ahead are climate models.

And the majority of climate models actually do say that El Nino is likely to strengthen in the eastern Pacific over the coming century. Well, how important is it to establish this link between a warming climate and strengthening El Nino's? Well, I think our work has given us one more brick in the wall, if you will, of the idea that we're building a story and an understanding of El Nino. And part of that story is understanding. whether the conditions that we're seeing right now are unusual. And our data says, yes, they are unusual. And we're able to say that with some confidence, given the amount of data that we've collected in the past.

So that tells us that there is a trend happening now. And I think that was an important gap that we didn't know quite as clearly, especially in the Eastern Pacific. We had a little bit of a hint that this was happening in the Central Pacific, but we didn't really have a clear picture in the Eastern Pacific until this study. And so now that we've got that, you know, better understood, I think it helps us rule out some other possibilities like that these strong Al Ninoes we're seeing are just part of El Nino being its natural self. That's not what our data say. Now, we've been talking about El Nino in the Pacific, but how far reaching are its effects around the world?

El Nino creates impacts all around the world, all through the tropics, all around the Pacific basin. and it does things like it rearranges where we find tropical storms. You know, the warm waters over the Pacific generate more and stronger tropical storms during strong El Nino's, and we're seeing that already this year, right? Conversely, an El Nino tends to suppress tropical storms in the Atlantic, so that's helpful, but, you know, ramps them up in the Pacific. Another thing it does is it rearranges where droughts and floods are formed. So we may see floods in places that are usually dry and droughts in places that you

usually have a lot of moisture. An example of that might be in South America where right now we're seeing lots of rainfall along the equatorial coast near Peru and Ecuador. At the same time, up in Central America and Panama, they're experiencing a drought that is slowing down shipping in the Panama Canal. Even further afield in the Indian Ocean, we tend to see warmer conditions across much of the Indian Ocean during El Nino, and we find that with the increased rainfall along eastern Africa and coast in Kenya and Tanzania, at the same time that we see reduced rainfall in southern Africa and in the Horn of Africa.

Wow. So El Nino really mixes things up all around the world. So what kind of effects are we looking at here in North America? Well, during an El Nino, we expect to see more rainfall coming into the southwest, where we would normally have dry conditions. So in some ways, that is welcomed, although it can take the form of tropical storms

that come in with great intensity, and it can overwhelm systems that aren't used to a lot of rain. We tend to see more rainfall across the southeast as well. And then we'll see less rainfall in the northwestern part of the U.S. and in southwestern Canada where we would normally see rain. Because what El Nino does is it shifts the path of those storms southwards. So what can countries do at this point to protect their populations from the worst effects of the super El Nino?

Yeah, the ability to prepare for El Nino's impacts really takes some resources, right? And it's a challenge to prepare. But I would say that one benefit we can point to is that we understand a lot about what the typical pattern of extremes that an El Nino event will cause. So I've just listed some of those. And these are going to be different in different areas. But we can expect, for example, that areas that are prone to flooding during El Nino can prepare in ways that minimize the damage and risks to the population there. For example, clearing out culverts so that they don't get clogged easily. In the case of drought, one can think about stockpiling food or think about planting different kinds of crops if you have enough

warning. So there are ways to prepare, but each of these ways is very dependent on the particular impacts in a particular location. Just one last thing. What kind of emotion? What kind of emotional emotional toll, does this take on you to be the bearer of bad news that our actions will likely have such extreme effects on the weather? Oh, boy. I mean, I think you hit the nail on the head there. It's really difficult to be talking about these things in this dispassionate scientific language and at the same time thinking about the impacts that El Mino can have on people, on ecosystems, on places that we care about. not see a way to solve this problem that's immediate. I think by pointing to the connection between Al-Nino and global warming, it may give us one additional push to think and do more about reducing our dependence on fossil fuels and getting off of the greenhouse gas producing fossil fuels that we depend on now.

I mean, pushing us towards renewable energy. We know renewable energy is cheaper, and we know that most of the new electrical capacity that we've put into place in the last few years has been in renewables. So that's something we really need to accelerate to get out of this. And I hope that this is one additional kick that gets us down that road. Dr. Cole, thank you so much for your time. Thank you for your interest. I appreciate it. Dr. Julia Cole is a professor and chair of the Department of Earth and Environmental Sciences at the University of Michigan. I'm Bob McDonald, and you're listening to Quarks and Quarks on CBC Radio 1 and streaming live on the CBC News app. Just go to the local tab and press play

wherever you are. Coming up later in the program, why Great White Sharks are thriving in Atlantic Canada. So what we're trying to do is protect the places that are important for the most number of different species. One of the species that is part of the study that we're tracking are the Great Whites. This week on two blocks from the White House. Donald Trump is busy with international diplomacy this week from China to the UN. But he doesn't have too many friends in other countries these days. So we're asking, is Donald Trump even interested in having allies? Find and follow two blocks from the White House wherever you get your podcasts.

And watch us on YouTube. New episodes drop every Wednesday. The Suriname Toad is easily one of the most unusual amphibians on the planet. Videos of the Toad giving birth go viral showing the fully formed brood erupting from holes in its back. But this strange-looking creature has other superpowers, too. Though it's nearly blind and lives in the murky waters of the Amazon basin, the Suriname Toad is a deft hunter, able to see using only its fingertips. In a recent study, scientists discovered just how their unusual fingers sense their prey. Dr. Duncan Leach is a neurobiologist at UCLA and is the senior author on this research. Hello and welcome to our show.

Thank you. First of all, describe this strange toad. What's it look like? How big is it? It's about 15 to 20 centimeters, and it looks like the average frog or toad that you might expect, but completely flattened down. It is camouflaged and is adapted to look a lot like a leaf that you might see in the bottom of a puddle or in a pool. And that is one of their main strategies for avoiding predators. but it also has a kind of a unique triangular shaped head. Wow. So 15 to 20 centimeters, that's about the size of my hand, right? Yeah.

You're saying if I took a frog and just squished it between my hands, that's what I get. Exactly, right. If you just compressed it completely down flat between your hands. And yeah, it does not resemble most people's mental image of a frog. Now, what about its fingers? What do they look like? Right. The fingers are quite unique in that,

So frogs have four fingers on their hands, and on each of these, if you see one in an aquarium, you might be able to see. It looks like it's a little bit frayed, but those split into four different lobes on each of the fingertips, and then subsequently each of those lobes splits four times again in sort of this fractal pattern. So in total it has 128 of these little lobes that are projecting off of its fingertips. Well, what are these lobes like if I was to look at them under a microscope? They're rounded dome-shaped lobes, almost the heads of a pin, but even smaller than that. How then are they used to catch prey? They function as a very acute touch surface that gives the frog a sense of potential prey as it's moving through its environment.

So how sensitive would the frog's fingertips be, say, compared to my fingertips? They're at least as sensitive as your own fingertips. We actually employed tools that are used in neurology to assess human fingertip sensitivity. So these are calibrated filaments that impart a specific amount of force to test in different kinds of sensory deficit type conditions. And these proceeded as far as we had among our tools. So we don't know the upper threshold of how sensitive they are, but definitely a lot of, along the scale of tenths of millinutons. So very sensitive.

What then can they actually sense? I mean, do they have to touch something and know the surface? That's a great question. So that they aren't actually, it doesn't require the animal making contact the way we are using our fingertips to actually palpate and touch the environment. When you might encounter these frogs, if you were searching in the Amazon or the Orinoco Basin, you would see them in largely stationary. So they're in a kind of a funny posture, almost like the goalposts of an American football stadium.

So you would see them with their arms outstretched and with their fingers not moving. So they adopt this position and are ambush predators, and they're just waiting for a fish to swim by. So if a fish passes within about half a centimeter to a centimeter of these frogs, the frog will launch into this ballistic sun. suction feeding and then completely suck in fish or warms or anything that is moving and excites the fingertips. So it doesn't actually require direct contact with the fingertips themselves. Oh, so they don't have to touch the prey?

They can, what, they feel the water, the movement of the water? Right. It can feel the wake or the hydrodynamic motion of the potential prey or something moving in its vicinity. That's astounding. So how long does it take the frog to catch the fish? It's incredibly fast. They can do this on the scale of tenths of a second,

so 100 milliseconds or less to completely suck in and overwhelm the prey. They're doing this by opening their mouth and completely expanding their entire body cavity to make a vacuum that sucks in all of this water. And then they're regurgitating out the water simultaneously as they're securing the prey. Almost the whale. A whale inhales a large volume of water to feed with baleen.

Poor fish doesn't have a chance. Right. No, no. Completely getting swallowed alive. Now, if the frog has this incredible sensitivity, these 128 lobes on its fingertips, and it can detect just the water, what's going on in his brain?

How does that all come together? That was a very interesting finding in that we found, found that a significant portion of the brain is dedicated specifically to processing touch specifically from these fingertips. So frogs, of course, are amphibians and have a brain organization that's very different than mammals. And we know a lot more about the way touch is represented and how it works in a mammalian brain than we do in most other animals. But what we found is in one of the key relays of where they are representing touch from different areas of their body, that area is largely devoted to specifically the fingertips.

So despite the fingertips being on the body, a very small amount of the surface area, they occupy a great amount of the real estate of this map of the body that the frogs have that represents their touch surface. Wow. Now, what about their vision? Do they see the fish coming? They can see shadows, but they cannot see completely well-formed images. Their eyes are relatively small, and many of the aquatic environments that they live in are quite murky. So it appears that they have, rather than allocating a lot of neural resources to the visual system,

they're using a lot of it for their sense of touch. And in fact, we did different kinds of behavioral experiments, including recording them under infrared light, under wavelengths that they cannot see. And they were just as successful at catching fish without the use of their vision, presumably. Boy, so they just lie there with their arms out waiting for a fish to come by

and as soon as they sense it with their fingertips, they grab it. That appears to be the story, yes. Are there any other animals that have a similar sort of ability to essentially see with their fingertips? With fingertips? perhaps less, that has been less studied.

But there are definitely examples, including some in Canada, the star-nosed mole. You might be aware of that. It has elaborations, almost like tentacles they're projecting from the skin of the surface of the nose. They are using this to palpate their underground environment and to quickly distinguish potential food based on their sense of touch. So it makes sense if you live in a dark or a murky environment that, your sense of touch is going to go farther than your sense of vision. Absolutely. That makes a lot of sense.

Dr. Leach, thank you so much for your time. Thank you. Thanks a lot. Duncan Leach is an assistant professor of integrated biology and physiology at UCLA, University of California at Los Angeles. A longstanding debate about every kid's favorite dinosaur has finally been resolved. The T-Rex, a dinosaur that lived about 66 to 68 million years ago, was warm-blooded, according to newly published research.

Scientists at the University of California at Los Angeles looked at the chemistry of tooth enamel from two T-Rexes to figure out their body temperature. Yes, that's right, from a tooth. Here to explain just how this works is Dr. Aradna Tripati. She's a geoscientist at UCLA and was senior author on this paper. Hi, welcome to our show. Hello, Bob.

So first of all, tell me about the two-dropoddy. dinosaurs whose teeth you studied? Yeah, thanks so much. So one of the dinosaurs we studied, his name is Thomas the T-Rex. He is an iconic teenager who lived 66 million years ago. Today, you can see his skeletal remains in Los Angeles at the L.A. County Natural History Museum. He's actually the centerpiece for their dinosaur gallery. And, is the star really of this paper. We had a chance to measure two teeth and literally take those teeth into our lab at UCLA, drill some tooth enamel off of the surfaces of the teeth with a low-speed drill, clean that powdered tooth enamel, and then measure it on the mass spectrometers in my lab.

And there was also a second dinosaur that you examined? We got tooth fragments from a second dinosaur that we know is a T-Rex, but we don't actually know anything more about the individual. Now, the idea of warm-blooded dinosaurs is not really new. I mean, we've been hearing about this for a long time as a debate. What kind of hints have there been in the past that they might have been warm-blooded? What's really interesting is that there's been a debate over whether dinosaurs have been cold-blooded or warm-blooded, basically for over a century.

but nobody's had an exact determination of body temperature for T-Rex. The technique that we're using, we're looking at the chemistry of tooth enamel. Tooth enamel is not very porous. It's very resilient to chemical alteration. Then we could use the isotope chemistry of these teeth, the clumped isotope chemistry, which is what we measure in my lab, to get a direct determination of body temperature. This is basically the next best thing to literally sticking a thermometer in the animal's mouth, right? And so what we're getting is a direct body temperature determination for the time that that tooth formed.

What temperature did you come up with for the body of a T-Rex? It's about 36 degrees centigrade. That's the body temperature that's really, really similar to our own. It's similar to an elephant. Wow. Yeah, what's also extraordinary about this is that we were able to measure crocodilians, you know, crocodile relatives from the same formation, and they came out at a colder temperature. They came out closer to like 31 degrees centigrade.

And so the third piece of information that we were able to collect, we were able to make measurements of clumped isotopes in fossil shells. And so those give us an idea of what environmental temperatures were. So we have environmental temperatures, body temperatures of crocodilians, which we know are cold-blooded, reptiles. And then we also have body temperatures for multiple specimens of T-Rex. And all of these were different from each other. The crocodilians and T-Rex were both warmer than the environment that they lived in, and T-Rex was warmer than the crocodilians with a body temperature similar to that of modern endotherms, and the body water chemistry we were able to look at by measuring oxygen isotopes,

so different isotopic system in these teeth and from these fossil shells, shows us that the body water chemistry of T-Rex looks bird-like. And in crocodilians, it looked like modern crocodilians. And so it also showed that their water budgets, you know, looked very different from each other. So another piece of evidence that the physiology of T-Rex was much more similar to modern endosarms. Wow, that's amazing. And you do all of this from teeth. I have to ask you, how did you convince someone to give you a tooth from a terranosaur? What it took was actually more than a decade of work.

Rob Eagle, who is the professor that led this study with our graduate student, Randy Flores, who did all of the really careful lab work. What Rob and Randy really have spent a lot of time doing with some of the technical specialists in my lab is adapting the clumped isotope method so that we could measure very small samples. And that work has been going on for over a decade. Rob Eagle, when he started doing clumped isotope work at Caltech,

he actually took modern samples of different types of vertebrates and demonstrated that the chemistry of modern tooth enamel from different types of organisms reflects their body temperature. And then he started measuring fossil sauropods and fossil mammoths. So looked at a range of different extinct organisms and was able to reconstruct their body temperature. And then where we were able to really adapt the methodology in my lab

to look at very, very small samples, really pushing the envelope of the work and really do method development, not the most glamorous work, but it's now opened the door up to us being able to look at T-Rex. And so that's why we were able to get these specimens. Well, now that you've proven that the T-Rex was warm-blooded, how does this change your understanding of how the animals lived? We can explain why Tyrannosaurids are found in places like the Arctic.

Why we have in places like Alberta, why we also can see distributions down to the subtropics, basically a Tyrannosaurid with a body temperature like this one is one that is an endotherm, it's one that can live in this breadth of environments. And so I think that's really important, you know, because body temperature tells us about the thermophysiology of an organism. And that means that that's really what sets where an animal can live. It lets us start to model their habitat and their distribution. which is exactly what was also a part of this study, which is really exciting.

What it also lets us do is it sets the stage now for us being able to look at other dinosaurs for which there are only small amounts of sample available. This is the first time this has been done. We now have from Rob's work, from the work from my lab, from the work of other groups. We have about six body temperature points spanning roughly 100 million years for this lineage. So, of course, we have modern birds and other avian and non-avian reptiles. We have, we have sauropods, we have T-Rex, we have a handful of other taxa. And so we can start to imagine that we're going to be at a place now where in a few decades,

will have looked at many other organisms and can start to unravel their physiology and even the evolution of thermophysiology in dinosaurs over time. Dr. Tripati, thank you so much for your time. Thank you, Bob. Dr. Aradna Tripati is a professor of Earth Science and Climate Science at the University of California, Los Angeles. Taurus aren't the only visitors coming to Nova Scotia this summer. White sharks are also swimming into our cooler waters.

of their massive seasonal migration. Two great white sharks were spotted swimming 800 meters from the shore near Rizzers Beach this past weekend. Just outside Halifax, a shark sighting forced lifeguards to clear the water earlier this summer. Spotting the fin of a great white shark slicing through the water is enough to make most people want to bolt in the other direction. But not Dr. Neil Hammerslag. Okay, well, let's head out to Mud Island and go from there. Great whites are endangered in Canada after their numbers crash from decades of overfishing. But now we have rules in place to protect them, and the great whites are back.

And so was Dr. Hammerslag, who grew up in Canada. He moved back near the end of 2022 after running a shark research and conservation program at the University of Miami. And he set up in Nova Scotia where he operates a shark expedition company. Hey, just guys, keep an eye out for the sharks. You never know when they're going to show up. up. Dr. Hammerslag is a marine ecologist and shark researcher, and he runs a program that tags and tracks marine animals to map biodiversity hotspots along the east coast of North America. Hello and welcome to our show. Hey, it's good to be here.

First of all, what draws great white sharks to the east coast of Canada? Yeah, that's a good question. What we think is it's plentiful, bountiful food options from fish to actually smaller sharks and rays to seals to tuna all those good things oh my god great white shark people well how does your work with the great whites factor into the overall program you lead to tag and track marine animal biodiversity hotspots if you can imagine you know you can't nor do you want to try to prevent fishing or human activity in all parts of the ocean and you know managers and policies makers need to prioritize areas for conservation. And so what we're trying to do is protect the places that are important for the most number

of different species. So what we're using is tracking data to figure out the kind of hot spots, the favorite spots of all different species to figure out the areas that are going to have the most bang for the buck when you think about protecting. And one of the species that is part of the study that we're tracking are the Great Whites. Now you go out and tag Great White Sharks. I have to ask, how do you do that? Well, to be honest, it's not that easy, so it's a good question.

You know, I mostly have tagged Great Whites and other species of sharks through mounting a tag to their fin because the tag needs to break the water's surface in order to transmit a message to a satellite that tracks them. So for that, historically and most traditionally, I and many others have had to catch them to attach a tag to their fin. But the thing is about capturing them is that it can cause some stress or behavioral alterations for a few days. So we lure the Great Whites to our boat with some pieces of tuna and things they like to eat. So they come by. and when their fin comes out of the surface for a few split seconds,

I try to use an air-powered rifle to fire an arrow or holding a tag with an anchor on it that essentially will hit the top apex of the fin and stick on there, and the shark swims away and doesn't even know about it. Wow. How good are you as a sharpshooter? Turns out I'm actually not bad, and that was surprising to me and probably a whole lot of people. You're a natural. Now, you've been out there doing this, studying the Great Whites for a couple of years off the Nova Scotia coast. What about this summer? What happened?

You know, we're actually in the middle of it right now. We're in the middle of our peak part of the season. Look, that's a gorgeous shark. I think what's been pretty interesting this year is that we started seeing sharks earlier than we did last year. collect environmental data as well every day. Everything from temperature of the water to the phase of the moon. And one thing that's certainly true as well is that the water seemed to be warmer earlier on. We had an extremely cold spring, and then all of a sudden it was summer. It wasn't gradual. And when the water is warmed, we started seeing the sharks.

And these sharks are migrating from further south when the water's warm. And so we do believe that there's a strong, pattern of the sharks being here related to water temperatures and with temperatures increasing and getting warmer earlier, so did the sharks show up. Can you identify individual sharks? Yeah, actually amazingly we can. Could it be shark robin? Different sharks have different patterning of where the white and the dark meet, and we can use

that to identify different individuals. So are you seeing the same individuals returning year after year? So some individuals we only see once, and some individuals we see through various points throughout a season. And this year, we've seen sharks that we saw last year. Now, the Great White Shark has a pretty nasty reputation, mostly thanks to Hollywood. As someone who's out there actually encountering them and, you know, putting darts on them, what do they really like? Yeah, to be honest, what you see on TV and in the movie theaters is, is nothing like what their true nature is.

They are actually really cautious. They're very careful. They do not want to waste energy. And they're very aware of one another. And we see them communicate through body language with one another, which, you know, social interactions show us that they are, you know, smart individuals. And even more amazingly, we can actually see. personalities in these sharks. Well, give me an example of an interesting personality that you've encountered.

When we think about our own family, or you can think of the personalities and there's characters among your family members, right? Everyone's got kind of like the crazy uncle or the shy nephew or cousin. And, you know, we see that in the sharks. You know, there are some sharks that are bolder than others, others that are more shy. I mean, one individual that we see and have seen last year and again this year we nicknamed mystic and this shark is just got a lot of energy and he comes at the boat and when he comes he always tries to outsmart us at least that's what it feels like he always seems like he's trying to get the bait from us but we try not to feed them we always pull the bait away and he always seems to try a different angle and different approach

and try to catch us not paying attention. And when we do pull it away from him, sometimes if we've done that a few times, he'll kind of swim away, is almost as if he's pouting, like we hurt his ego, which I know that's not the case, but it's just really interesting to see and think about.

Well, I mean, do they ever get the equivalent of angry, you know? Are you worried about that, that they might charge at you? No, because that's just not in their DNA. One thing is that I think most people don't realize, and we wouldn't know is that they don't waste energy. They're extremely efficient, and to be honest, getting angry is a waste of energy.

I see that when they naturally hunt seals. And if they attack a seal and the seal gets away, they'll take one or two chances at it. And if they're unsuccessful, they'll just go swim away and let that seal go because they don't want to waste the energy trying. And so I think that's a scenario here. Boy, your picture that your painting is so different

from what Hollywood gave us. So what do you say? If you think about it, the reality is that I think these sharks are actually a lot better to humans than humans are to other humans. Dr. Hammerslag, thank you so much for your time. My pleasure. Dr. Neil Hammershlegg is the director of the Shark Research Foundation and president of Atlantic Shark Expeditions in Nova Scotia. And that's it for Quarks and Quarks this week. If you'd like to get in touch with us, our email is Quirx at cbc.ca.

Our webpage is cbc.ca.ca slash quirks, where you can check out our past episodes and find out more information about the research we covered in the show. You can also follow our podcast, get us on SiriusXM, or download the CBC Listen app. It's free from the App Store or Google Play. Quarks and Quarks was produced by Sonia Biting, Rosie Fernandez, and Amanda Buckowitz. Our senior producer is Hannah Hoag. I'm Bob McDonald. Thanks for listening. For more CBC podcasts, go to cBC.ca.ca slash podcasts.