We speak with Nicola Quick about the ELUSIVE beaked whales and how they are able to dive to astonishing depths.
Listen to the full interview on The Deep-Sea Podcast
want to be notified when new interviews are released?
Nicola quick
Marine conservationist at the University of Plymouth and Dukes University.
I'm joined by Dr. Nicola Quick. Her research focuses on the ecology and behaviour of marine mammals, particularly on how marine mammals use acoustic signals and how anthropogenic noise affects their behaviour.
Thanks for coming on to have a chat with us!
You're welcome. Thank you for having me along.
We are a deep sea show, but it turns out there are some air breathing marine mammals that go into the deep sea. what are the big deep-diving species?
So there are a few of our cetacean species that like to head down to the deepest parts of the ocean. Probably the one that people know the best is the sperm whale. That's one of the larger whales that often features on whale watching trips in certain places. New Zealand being one of the common places you can go and see those guys. Another one is pilot whales. They're pretty deep divers as well. Although, in comparison to the next group I'm going to mention, the pilot whales are probably pretty moderate divers. And then you have the beaked whales or the family Ziphidae (or the ziphids as we call them). They’re what we term our extreme, deep divers, in the group of cetaceans.
And for a lot of folk, nothing is going to pop into their brain when they hear the term ‘beaked whale.’ So if somebody was looking at these whales, what would they be looking at?
Well, interestingly, they're actually quite a large family of cetaceans. So ‘cetaceans’ is the word for whales and dolphins. And they're actually the second largest family after the dolphin. So, there's actually 22 species of the beaked whales in the family Ziphidae. And getting that normal search image is quite hard because actually they're quite different in some of their their body shapes. Obviously, they're that nice streamlined shape that we associate with a whale, but they can range in size from 4 meters up to 13 meters, depending on the species that you're looking at. And often they sort of have quite bulbous torpedo shaped bodies almost ,with a small beak at the front that you might associate with something like some of the smaller dolphins. And then going into a shape at the back, their tails tend not to have a notch, like where we associate with other whales and dolphins. And then the really different thing about them is: unlike something like a big humpback whale that people might have seen on the TV that have these big white pectoral fins, beaked whales have very small pectoral fins. So those fins on the sides of their bodies are quite stubby, those little fins. And that's just to make them as streamlined as possible to help them as they're diving deep down into the ocean.
That's amazing. So one of the most diverse families of whales and dolphins, it's not one that pops up in our minds and that will dip into why they're so infrequently seen. What are they doing out there? How are they living their lives?
Well, you're right. They are actually one of the least known groups of mammals out of any groups of mammals. So that's that's why people don't have that search image in their minds. And the thing that probably makes them even less known to humans is where they're actually living. So these guys live in deep water areas and that can be off the drop off zones. Also they can be island-associated if you have some areas where there's some steep drop offs around islands. So those ones might be seen by people a little bit more frequently. But but typically they're in these deep offshore waters that are not really that accessible to your average human to get to, unless you've got a well-equipped boat to actually get out there and see them. And the really interesting thing with these guys is even though we say there's about 22 species, some of these have only really been described in the last couple of decades. And there's still a few of those species that we maybe only know from a skull that has been found washed up on a beach. And really out of all of those species there’s only three or four that are reasonably well described, and that's due to how far offshore they live, in areas that are harder for us to get to. And also, they're not one of these species that spends a lot of time jumping about at the surface like you might associate with something like a humpback whale.
They don't show off.
No, they don't tend to. It's not saying that they don't breach if they want to. They can. But yeah, they're not one of these “Look at me” species, like a humpback whale or dusky dolphin.
How are they spending their time if they're being all cryptic and avoiding us?
Yeah, I guess I'm generalising about beaked whales in general, but the one I study is the goose-beaked whale (Ziphius cavirostris). So that's the one that I know the most about. But there are a couple of other species. But for those Ziphius, they tend to spend the majority of their time under the water. So these guys have this pattern of diving where they they dive deep… and if we say on average, an hour to do a foraging dive. So a deep dive for them is crazy deep. I think it's thousands of meters down. They can dive and they forage. The only reason we're assuming they're foraging down there is because they create these echolocation clicks that other people have associated in other species to be searching for food. And these these sort of regular clicks you get, followed by these buzzes, which we assume is them capturing prey. So they dive deep, these foraging dives, and then they come up to the surface for about, on average, two minutes where they're actively breathing. And then they do this series of ‘bounce dives’. Some people call them shallow dives, which is slightly misleading because they then do these series of dives that to them, they're shallow, but they are still to 300-400 meters.
Oh, that's weird. It's almost like a deco-stop. They sort of stretch their body to its limit and then come back up shallower.
Well, yeah, that's sort of the theory in that: they do these big deep dives and then they're doing these shallower dives, which we call an inter-deep dive interval. So it’s just that time that they're still diving, but it's between those big deep dives before they they head out again. So you get these patterns of one really deep dive and then maybe four or five shallower dives with 2 minutes at the surface between and then they're back to a deep dive.
That's incredible.
Yeah, it's really interesting and I guess I've looked quite a lot at that diving behaviour and we can get into that, I guess, with how they're doing that. But yeah, it's a really interesting approach to be dive that deep, breathe only for a couple of minutes, and then (for any other animal) begin deep diving again; to them, 300m is shallow.
“... and to them, 300m is shallow.”
On the deep dives, do they seem to be heading for the seabed? What are they doing when they get down there? Have we done any gut content analysis, or do we know from any of the strandings what they're eating?
Yes, it's a good question. So back to the first bit about are they diving to the seafloor? Yes, we think that's what they're doing. We've been trying to explore that a little bit with some of our acoustic tags that we put on the whales to see if we can get really cool bottom-echoes (echoes from their echolocation clicks that are coming back off the bottom.)
You're listening in on them!
Yeah, listening to see what they're doing; how they use that environment. So yeah, generally we think they tend to forage within a few hundred meters of the seafloor. But with other populations, that isn't necessarily what they're doing all the time.
There's some thoughts on a paper of ours a few years back, finding these weird traces on the seabed, these weird little troughs at regular intervals. And the thought is that they are they're actually sifting through the seabed. They're pushing that snout into the sediments and looking for things buried or that we don't really know what they're doing down there.
Yeah, the whales go right down to the seafloor. So yes, they could be doing that. They have these really interesting dentitions, if you like, in that they don't have functional teeth. The males have these tusks at the front, so they're not like chewing food, as you would think of what humans do, but we think they're sort of sucking up prey as they're heading down to the bottom. So yeah, maybe they're sucking things up or maybe they're foraging mid-water. We do have some buzzes from our tags, where they're not right at the seafloor. So yeah, I think we're not really sure, to be honest, exactly what they're doing down there in terms of exactly what prey they're targeting and exactly how they're capturing everything that they're chasing. But generally the thought is squids and deep water fish. But I'm hoping you could tell me what of what they're going to be eating in those areas.
Image courtesy of Ritter et al 1999.
Well, it's got to be worthwhile. It's a huge effort. It must take so many calories to do this. So it's got to be profitable. They've got to be consuming more calories when they're down there. What's the average deep dive and what's the kind of record we currently have for them?
So on average, they're diving for about an hour at a time, but they're not foraging for that whole time. We’re looking into those different foraging strategies in terms of they don't tend to actively echolocate for a lot of the dive, which things like sperm whales and pilot whales do. People find sperm whales in the wild by using a hydrophone because you can hear that clicks and then you can track them underwater. Because generally when sperm whales are under the water, it's clicking all the time, whereas beaked whales tend to dive and then just start clicking on the bottom. When they're foraging, they do echolocate for a reasonable amount of that dive, but there seems to be a very definite period when they're clicking and actively foraging and the rest of the time they're very quiet. At least they're not making what we think are foraging clicks. So it's about an hour that they’re diving. But as I said, the proportion of time they're foraging is less than half of that.
They have been recorded down to almost 3000 meters, which is insane. Yeah, but the whales that we look at, 1500 meters is probably the average. We have recorded some long duration dives, like crazy long duration dives, well over a few hours, which seems insanely long for them to be under the water, holding your breath for multiple hours.
Yeah, diving to over 3000 meters deep is nuts! And actively foraging as well.
Right, that's the thing. They’re not just having a rest down there. They’re not hibernating or something, they're actively doing something down there.
So you can't do something like this lightly. There must be loads of adaptations that they have to do deep diving. And you mentioned the lungs collapsing. What are some of the super deep sea adaptations to air breathers?
It's interesting because for these these deep divers, you have a division of resources, if you like, that that most mammals don't have to deal with. So you've got air at the surface and food at depth. And you have to go through a different physiological state to access to your main really important resources, which is not something that generally happens in mammals. So it's quite interesting.
So all divers, when they're there foraging at depth, they can't breathe, obviously. So they need some way to have improved oxygen storage in their tissues, in their blood to be able to provide their organs with oxygen while they're diving. And remember, they're actively moving as well. So there's metabolism going on there. They obviously deploy this dive response, which we we do see in human free-divers as well; where you get a slowing of the heart rate. Your heart rate slows and there’s a redistribution of blood flow. And this is what we think happens with the whales of sea. They distribute blood to those more important organs e.g. your brain and your heart, as opposed to sending blood to the peripheries of your limbs and your skin. So they have that and, I'm not a physiologist, but they have a lot of physiological adaptations with the types of muscles they have, the amounts of myoglobin, (which obviously is very good at storing oxygen in the tissues) and even how much they invest in things like brain tissue. They actually have quite small brains, so they invest less in these sort of tissues that are metabolically expensive, if you like. So there's a huge range of adaptations that that these guys have.
“They have been recorded down to almost 3000 meters, which is insane.”
I was reading that the lungs collapsing is actually a good thing. Because diving that deep, they would have all sorts of gas issues. So it was almost by the lungs collapsing, It kept them safe from getting knocked out at depth. And then on the way back up, just as they were approaching shallow water, that's when the lungs would would re-inflate, not with any fresh air, but just with the same air that was in there, but compressed away, would give it a little oxygen boost.
Yeah, they are really fascinating, because obviously, most animals have got super adaptations to the niche’s they exploit. The hydrostatic pressure that you're dealing with, is a real challenge of diving, because your air-filled structures obviously get compressed and that would essentially mean nitrogen would enter your bloodstream. So that's where your risk of the bends comes in. So by collapsing those air-filled structures, you're regulating the chances of that happening. There's also evidence from a lot of divers I don’t know if it happens in beaked whales) but, I believe some of the seals almost breathe out before they dive. In a way, to get rid of that excess air because they're going to collapse those those air filled structures.
So, yeah, it's these two challenges of metabolising without respiration so their tissues are constantly using oxygen at depth, but obviously they can't renew their oxygen stores. And then that hydrostatic pressure where air-filled structures are going to be compressed. And potentially, as you come back up, there's at risk of the bends as as nitrogen would enter the bloodstream in the bubbles and cause the bends. So they're clearly super adapted to be able to to deal with those challenges.
So to flip to your work, You've mentioned acoustic tagging, you've mentioned recognising individuals. What is your research like? How are you studying something that seems to be well, so well hidden?
Yeah, I sort of flip between really liking beaked whales and really hating beaked whales. They’re really challenging to work with. But it's super rewarding, I guess, when you can work with them. With any marine mammals, I think a lot of the well-studied groups and populations are in places where they're accessible. We're very lucky in the study site that I work with, and I have to mention here: before I was at Plymouth, I was over at Duke University in the US working with a great group of people out there, that developed this study on beaked whales.
So Andy Reid's group and Doug Nowacek’s group. Basically they were out of Cape Hatteras, which is on the east coast of the US. So there's a drop off quite close to shore. But yeah, it's sort of an accessible place for beaked whales. But when they were out there doing some other studies, they took some great observations of beaked whales, and then we were seeing them again and again. And then there was another group that were running some aerial surveys that spotted these guys, these beaked groups out there, and then a student put out some acoustic recorders and we started getting detections too. So we're building up an area of where there's a hotspot of these beaked whales.
So it's challenging when you're out there because you can only see them in very low sea states. So sea states, zero and one, which is basically when there's no white water on the surface. This is because they're very, very cryptic. They just sort of come up, they breathe and they go down again. So a lot of the time, it’s looking at the surface of the water and seeing nothing. And then when we do see animals, you've got a very short window of a few minutes to actually get over and look at these guys.
Image courtesy of Ritter et al (1999)
We spend a lot of time taking photos of them because with all marine mammals, generally, there's some part of their body that has natural marks. And whether that's their dorsal fin, that's usually the easiest thing because it sticks out above the surface of the water. So you can take photos of those dorsal fins and you can match individuals because once they get those marks on their fins, they don't tend to change unless they get more marks over the top. If you get enough regular photos, you can match individuals over time. So that's how we know that we've seen the same individuals. With the Cuvier’s beaked whales, they have these really different body colorations. As the males get older, they get more white, which is really interesting. I’m not quite sure we know exactly why that is. But a white whale is much easier to see than a brown whale. So it's really just looking and putting yourself in the right position and spending a lot of time out there looking. Obviously, we have many days where we see nothing, but we have many great days as well, where we where we do see them.
And you're actually getting tags onto them?! How, how are you managing to approach and get something onto the body?
Yeah. So the tags that we use these, these sort of D tags, these archival tags and D tags were, developed by a group of very clever people at Woods Hole, lead by Mark Johnson and Peter Tyack, a number of years ago. And they're very specialist archival tags that record accelerometery information and then acoustics. We're able to just put them onto the whales with a very big, long carbon fiber pole that just sort of sucks on the back of the whale. So it's not an invasive tag. And then after, we have to think about how long we're going to put them on for, because where we work, if the tag pops off then it could be off on the Gulf Stream across the ocean, because you have to be able to go and pick it back out the water. So it's very much you need people that have got strong arm muscles, and very special skills. So we've got some great boat drivers that have got lots of experience driving around whales. You have to approach very carefully and you have to often take many services, many hours watching the whales to know exactly who you're going to try and tag. So and it's all done obviously under permits from the Marine Fisheries Service and now under the Marine Mammal Protection Act in the US. So it's a very it's a very strict permitted activity, and only a few people can actually do it. So we're very lucky that we have the skills in our field team to be able to do that.
And this might be out of your area of expertise, But you mentioned that we have the same dive response or a similar Dive response. Why have we still got that? Is this something that's within most mammals?
Yeah, it's a good question. And as you know, I'm not a physiologist or human evolutionary biologist. But yeah, I think just for any any air breathing mammal, there is that in-built response, perhaps from the original evolution of mammals from the ocean, that you have this inbuilt response so you don't actively breathe underwater. And it’s sort of everybody goes into a preservation mode because it's not your normal habitat, by conserving energy and taking those those measures, I guess, of slowing heart rate. Although I think probably for the average human, when you're thrown into cold water, I'm not sure that the dive response kicks in as well as it should.
Is there anything that is often misreported that you'd like to set the record straight on?
I think people generally just think sperm whales are the deepest diving whales and the beaked whales definitely go deeper than them. So that's probably just because they’re more well known and people are much more likely to have seen them or heard about them. I think they're quite happy just getting on with their everyday lives. And generally they are reported to strand with military sonar. But yeah, that's how they were getting more visible to people was this link between human activities and beaked whales, which is where a lot of my research was looking at how that diving changes with the effects of noise, as the link pretty strong.
so it does seem to be our activities that are disrupting them?
Well is is complicated. There's a couple of published papers where they do seem to react in terms of a behavioural response. But we don't really know the mechanism and that's sort of what we're looking for now. So I don't think it's unsurprising, though, that if there's a loud noise somewhere, then things respond to it. But there's certainly suggestion that some mass strandings in beaked whales are associated with military activities in different parts of the world. So there's definitely this published information on that.
actually, I had a past life as a marine mammal observer And one of our best tools, especially for the cryptic species, was pams (passive acoustic monitoring). I would have to do a search for marine mammals in the area before they could start acoustic acquisition. And we’d miss these guys. They're quiet at the surface and really, really subtle. it would be really hard to mitigate against disturbing them other than knowing that they're in the area.
Yeah, definitely. And one of the things that has come up is their responses to sound. As they do (potentially) stop clicking as well. If there's lots of noise and you interrupt their foraging behaviour, then that could obviously have knock-on effects. But yeah, in that instance, there's something going on. So they're just even more quiet than they would normally be. Their instinct is very much to hide. But I guess the main concern with noise is that maybe there's a bigger impact on some of those populations, but we really don't know that much yet. But we're getting there.
There's so much we don't know for such a large group of mammals, right?
Yeah. Well, it's one of the least nine groups of mammals. And there's all these just fundamental basic questions, even for our work. Now we know so we can infer when they're foraging from the clicks. But in terms of other behavioral state, oh, we don't really know. Like when when do they sleep? When do they digest food? When do they reproduce? When do they socially interact? When, you know, when do they do all these things that other mammals do? Yeah. How do you coordinate? How do you find your pod again?
Yes, the more I think about it, it's really difficult way of living.
It's fascinating. And we had a one of the guys I work closely with, Will Chaffey, he's done some great manuscripts on looking at social cohesion and whales, and whales potentially diving together. So we do believe there's some social aspect to it. But again, how do you conduct those social relationships 2000 meters down when your body's turned off? And then how do you find each other again in this vast ocean?
There's still so much to learn!
thanks for coming on and sharing sharing what we do know. I have a new-found appreciation for them.
No problem. Thank you.