What Hyena Giggles Really Say

A spotted hyena in Kenya. Photo by Liaka ac, CC BY-SA 2.0.
A spotted hyena in Kenya. Photo by Liaka ac, CC BY-SA 2.0.

Spotted hyenas may be the chattiest carnivores on the planet. They whoop, rumble, low, and laugh, announcing their presence wherever they go. But what do all these calls mean?

Zoologist Kay Holekamp laid out the spotted hyena repertoire in a 2011 New York Times field journal. So far as we humans are able to understand, each category of call carries a general meaning that can be modulated by the sender to varying effect. Spotted hyenas low when they want to team up, “alarm rumble” to raise a red flag to approaching danger, and groan to greet cubs at a den, who then “squitter” to demand milk from mom. And their trademark giggle? That’s nervous laughter. Spotted hyenas usually titter when they’re being attacked, harassed by another member of their clan, or frustrated.

But there are more details embedded in hyena calls than we usually pick up on. In a 2007 study, Holekamp, Kevin Theis, and colleagues reported that spotted hyena whoops – their haunting, long-distance calls – reflect details about the age, and sometimes sex, of the hyena sending the signal. By looking at the acoustic details of 117 whoop bouts from 60 different hyenas, the researchers were able to discern that whoops become deeper with age and that the calls of non-juvenile males and females could be distinguished from each other (perhaps because the larger females have bigger chests that give them a deeper pitch). If you were a hyena, your whoop would carry essential information about who you are.

Mother hyenas grunt to draw their cubs out, and those cubs "squitter" to beg for milk. Photo by Budgiekiller, CC BY-SA 2.5.
Mother hyenas grunt to draw their cubs out, and those cubs “squitter” to beg for milk. Photo by Budgiekiller, CC BY-SA 2.5.

A hyena’s giggle is even more distinctive. A 2010 study by Nicolas Mathevon and colleagues on 695 giggles made by the University of California, Berkeley’s captive hyena clan (shuttered last year, sadly) found that the carnivore’s characteristic laugh carried cues about the sender’s age, status in the clan, and perhaps individual identity. This is all critical information for a social predator. If you’re going to work as a group, you need to know who’s talking as well as what’s being said.

And while some of these details might be lost on other species, hyena chatter can carry critical information for their carnivorous neighbors. Cheetahs, zoologist Sarah Durant discovered through playback experiments, will leave an area if they hear the sounds of lions or hyenas. In fact, Durant observed, the sleek cats were even less likely to go on the hunt after hearing the calls from their competitors. What was the point of bringing down dinner if a hyena might swoop in and steal it?

Lions are another matter. Despite their regal reputation, these burly felids often play the part of kleptoparasites. Lions have no qualms about bullying weaker carnivores off their kills, and, as argued by Hugh Webster and colleagues after playback experiments, lions will eavesdrop on the calls of other species to zero-in on an easy meal. Wild dog calls always generated interest, the researchers found, but male lions or mixed groups of male and female lions would also approach spotted hyena vocalizations in the hope of some grub on the go. At least hyenas can mitigate the risk of losing their lunch. One population in Zimbabwe started traveling in mid-size groups, rather than forming large foraging parties, in response to an influx of lions.

Short of a Babel fish, we’ll never be able to translate hyena giggles down to the level of “Hey! That’s my wildebeest leg!” or “Get lost, you mangy lion!” But hyenas don’t need the broadened vocabulary we have to keep their clans together. Their set of a dozen or so calls seems to suit them fine, with each hyena adding their own unique voice to the chorus.


Durant, S. 2000. Living with the enemy: avoidance of hyenas and lions by cheetahs in the Serengeti. Behavioral Ecology. doi: 10.1093/beheco/11.6.624

Mathevon, N., Koralek, A., Weldele, M., Glickman, S., Theunissen, F. 2010. What the hyena’s laugh tells: sex, age, dominance and individual signature in the giggling call of Crocuta crocuta. BMC Ecology. doi: 10.1186/1472-6785-10-9

Theis, K., Greene, K., Benson-Amram, S., Holekamp, K. 2007. Sources of variation in the long-distance vocalizations of spotted hyenas. Behaviour. doi: 10.1163/156853907780713046

Webster, H., McNutt, J., McComb, K. 2010. Eavesdropping and risk assessment between lions, spotted hyenas, and African wild dogs. Ethology. doi: 10.1111/j.1439-0310.2009.01729.x

Sabercats and Other Carnivores Kept the Ice Age World Green

A Smilodon angles to get a better bite on a sloth at the La Brea Tar Pits and Museum. Photo by Brian Switek.
A Smilodon angles to get a better bite on a sloth at the La Brea Tar Pits and Museum. Photo by Brian Switek.

The huge herbivores of the Ice Age were ecosystem engineers. Wherever they went, mastodons, sloths, bison, and their ilk changed the landscape by eating, defecating, trampling, and otherwise going about their plant-mashing business. But they were not isolated agents. Following out the engineer analogy, the megaherbivores of times past had managers. These were the sabercats, hyenas, wolves, and other predators past.

Many Pleistocene carnivores certainly look menacing enough. The long fangs of Smilodon have made it a staple of museum halls as well as schlock horror, and the thought of staring down a giant hyena is enough to send a shiver down my spine. So given that some prehistoric predators had such impressive weapons it’s not surprising that we’ve often imagined them setting into mammoths and other Ice Age giants. Bigger prey requires bigger cutlery, right?

Well, not quite. Many of the most iconic Ice Age herbivores were simply too big to kill. It’s the same reason why lions don’t chase after adult elephants. Clawing into a pachyderm is a high-risk scenario, even considering the fleshy reward, and fossil evidence has suggested the same pattern held in the Pleistocene. Smilodon didn’t take on adult mammoths and Megatherium, for example, but often targeted camels and bison instead. Large size was a refuge was most Pleistocene giants. But their offspring were a different story.

In a new study surveying the effects of large carnivores stalking the Ice Age landscape, University of California, Los Angeles paleontologist Blaire Van Valkenburgh and colleagues found that the young of many large Pleistocene herbivores would have been right in the sweet spot for hungry carnivores.

Part of the analysis involved sizing up the predators themselves. For starters, Van Valkenburgh and coauthors point out, not only were many extinct Pleistocene carnivores significantly larger than the predators that survived them, but each “carnivore guild” in the sample included a greater number of species in the past than comparable ecosystems today.

Even just looking at the felids, the researchers write, “nearly all Pleistocene predator guilds found outside of Australia included at least one and often two species of large sabertooth cat.” This pattern is directly related to the number of big herbivores there were to eat. Even in modern ecosystems, Van Valkenburgh and colleagues point out, the likelihood that three or more large carnivores might be present steadily increases. In addition to the herbivores creating more open habitat that give predators the opportunity to hide along the forested margins, there’s simply more meat to carve up.

Much of that flesh came in the form of juvenile giants. Even though we tend to think of adult specimens embodying any given fossil species, all prehistoric animals had to grow up. And just as with modern species – like the 74 juvenile elephants taken by lions over a four year period in Botswana – the little ones are vulnerable. Juveniles would have been even more at risk in the Ice Age, when apex predators were larger and there were far more of them.

Baby mastodon - like this one at the La Brea Tar Pits and Museum - would have been vulnerable until they reached about six years of age. Photo by Brian Switek.
Baby mastodon – like this one at the La Brea Tar Pits and Museum – would have been vulnerable until they reached about six years of age. Photo by Brian Switek.

Drawing from data on prey selection by modern carnivores, Van Valkenburgh and colleagues applied the same ecological arithmetic to the fossil record. While a solitary extant lion probably can’t capture even a two-year-old baby elephant, the paleontologists found, a lone Smilodon, Homotherium, cave lion, or other large cat would have been capable of hunting a baby mammoth or mastodon in the two-to-four-year-old range. (A sabercat den full of baby mastodon bones in Texas supports this contention.)  The chances of the Pleistocene predators only got better if they formed a pride, and social strategy was a boon to packs of wolves and clans of hyenas, too.

So while none of the Ice Age carnivores could have taken on an adult mammoth or mastodon, all of them – especially if they were social predators – were capable of tearing into the young. The big proboscideans would have been vulnerable until they were about six years old, which is a long time to have to be looking out for hungry eyes peering through the brush.

This is how the landscape was shaped by the subtle paw of the carnivores. Many paleontologists previously thought that Ice Age herbivores were too big to fail. That they existed at “saturation levels” because their size made them immune. But now Van Valkenburgh and coauthors have made a solid case that carnivores greatly influenced herbivore populations by preying on the young. This was violent, and even sad, but all a part of the constant ecological shuffle. Unchecked by carnivores, large herbivores can proliferate to destructive levels until they start eating themselves out of house and home. Smilodon, dire wolves, and other beasts of prey actually defended the plants – vegetation has no greater friend than a predator. That’s how large carnivores have been keeping the world green for millions of years , and I hope that our species can yield them the space to keep doing so.


Van Valkenburgh, B., Hayward, M., Ripple, W., Meloro, C., V. Roth. 2015. The impact of large terrestrial carnivores on Pleistocene ecosystems. PNAS. doi: 10.1073/pnas.1502554112


Saberkittens Were Double-Fanged for 11 Months

The La Brea asphalt seeps have me trapped. It seems I can’t visit Los Angeles without stopping by the Ice Age treasure trove to pester the paleontologists at Project 23 about what they’re finding and wander among the chocolate-colored skeletons inside the Page Museum. And in those halls, there’s one exhibit that never ceases to amaze me. Lined up behind glass are Smilodon skulls with two sets of fangs.

It’s actually not surprising that young sabercats temporarily carried two sets of upper canines. If you’ve ever raised a kitten, you may have noticed when their permanent teeth started to erupt and push their milk teeth out of the way. That’s a standard mammalian feature, as true for Smilodon as your household moggie. But juvenile Smilodon were a bit different. They were double-fanged for nearly a year.

The new numbers come from the latest paper on Smilodon tooth growth. Building on previous work by University of California paleontologist Robert Feranec, the study by M. Aleksander Wysocki, Feranec, and coauthors used a combination of geochemical traces, micro CT scans, and growth data from living carnivores to come up with absolute ages for major events in the early years of La Brea’s Smilodon cubs.

Little Smilodon started to grow their teeth while still in the womb. Wysocki and colleagues calculate that the felid’s teeth started to develop about a month before birth and those little grippers, slashers, and slicers grew at about 6 millimeters a month (close to Feranec’s earlier estimate of 5.8 millimeters a month). At this rate, Smilodon cubs had almost all their milk teeth by 4 to 7 months old, with their temporary baby sabers fully in place between 11.5 and 18 months.

Young Smilodon had their milk and permanent canines for about 11 months. Photo by Brian Switek
Young Smilodon had their milk and permanent canines for about 11 months. Photo by Brian Switek

But the permanent, characteristic, killing canines of Smilodon didn’t simply push the milk versions out. They came in alongside, and, according to the new study, the young sabercats were in the awkward position of having milk canines and still-growing adult sabers for about 11 months. This could’ve been a simple byproduct of growth. The adult canines required about 22 months to fully erupt, putting Smilodon at around three years old by the time their teeth had finally settled. Then again, Wysocki and colleagues write, perhaps this arrangement had a functional advantage. Maybe the milk teeth helped shield the flattened and relatively fragile adult sabers as they came into place.

The overall picture is that Smilodon upper canines erupted at a faster rate than those of lions, tigers, and other modern cats, but, by dint of the sabers’ size, that the process took a much longer time. This might provide some clues to how the sabercats grew up. Smilodon kittens younger than seven months may have required more attentive care from their mothers and stayed near their dens, which could explain why these earliest days of Smilodon life are totally unknown from La Brea. And depending on how effectively young Smilodon could have caught and dismantled prey while their adult canines were coming in, the findings could throw indirect support to the idea that these sabercats were highly social carnivores that relied on pride life while young.

As much as I’m tickled by the thought of awkward, double-fanged Smilodon youngsters, though, this new study has some serious implications for reconstructing past life. If paleontologists can determine when a certain skeletal part—like a tooth—starts growing and accurately measure the rate at which that feature grew, Wysocki and co-authors suggest, then they can pin absolute dates on developmental milestones in the life of that animal. For example, the new study was able to assign dates to when certain Smilodon skull bones fused because those events occurred during the span of time when the adult canines were growing. The same technique could be applied to other animals with long-growing teeth, such as mastodons and narwhals, to piece together a more precise view of how they changed with age. If you really want to understand the day-to-day life of extinct animals, it’s wise to look them in the mouth.


Wysocki, M., Feranec, R., Tseng, Z., Bjornsson, C. 2015. Using a novel absolute ontogenetic age determination technique to calculate the timing of tooth eruption in the saber-toothed cat, Smilodon fatalis. PLOS ONE. doi: 10.1371/journal.pone.0129847

T. rex Autopsy Goes into the “Belly of the Beast” and Beyond

Scientists, psychologists, and philosophers have all forwarded reasons why they think dinosaurs have such a tenacious hold on our imagination. Because dinosaurs are big. Because they’re scary. Because they provide kids a way to show they’re smarter than their parents. All may be true to some extent. But what we often forget is that it’s simply fun to imagine what these great creatures must have been like in life – to weave muscle and skin around the old bones and envision our favorite species bellowing their dominance over the planet. And it’s exactly that spirit the National Geographic Channel’s T. rex Autopsy tries to capture.

A Mesozoic riff on Inside Nature’s Giants, the one-hour program centers around the most glorious dinosaur ever created for television. The full-sized Tyrannosaurus, crafted by the Crawley Creatures workshop, may truly be the closest thing we’ll ever get to seeing the tyrant king in the flesh. And, fortunately, the show doesn’t spend much time getting bogged down in backstory. There are brief flashes of military planes, soldiers, and barking guard dogs as the carnivore’s carcass is wheeled before the show’s team of scientists, but how a tyrannosaur came to exist in our time is left as the conceit viewers have to make in order to dig into what follows.

Real paleobiologists carry the show. I was elated to see that researchers Victoria Herridge, Steve Brusatte, and Matt Mossbrucker form the heart – ha ha – of the program, although veterinarian Luke Gamble tries to steal more than a few scenes with more of a Crocodile Hunter style of presenting. (Seven minutes into the show, when the team is just starting to take in the dinosaur, Gamble jumps right in with a chainsaw to lop off one of the dinosaur’s feet.) Not to be unfair to the cast, who are researchers rather than actors, this approach sometimes comes off as a little bit stilted. The scientists know that they’re working with a giant anatomical model and, for example, know they shouldn’t be surprised that belly ribs make the tyrannosaur’s stomach difficult to slice open, but that’s just the way it has to be for the show to work. And the paleontologists still seem excited about the task in front of them – who wouldn’t want to dissect a life-size tyrannosaur, real or not? Their enthusiasm for anatomy shines through the scripting as they start peeling back the dinosaur’s flesh.

And it does get pretty gory. The show leaves no time to waste, making the whole operation a bit hack-and-slash. “We are the T. rex wreckers”, Brusatte gleefully says late in the show. But the wondrous thing about what Crawley Creatures made is that it’s complete with blood, guts, and stomach contents, most of which get smeared all over the scientists. Sitting inside a dinosaur’s open abdomen or going elbow-deep into its cloaca will do that. This is far better than any cgi effect. The practical Tyrannosaurus is so beautifully-crafted – from quill-like protofeathers on its back to the valves of its heart – that I didn’t want to miss a second of the anatomical exploration. By the end of the hour, I was a little disappointed that the dissectors didn’t have more time to look at the tail muscles, the system of air sacs that pervaded the dinosaur’s body, and other anatomical features that could have filled up hours more.

But even within the available hour, the show packs in the microstructure of the dinosaur’s bones, injuries, the anatomy of the eye, how to sex a dinosaur, and more. The fanciful approach is what allows the show to get into the details of dinosaur anatomy and biology in a way never seen on television before. Some of the vignettes – such as that dealing with its heart – are more speculative than others, but the program nevertheless offers a fast and furious short course on vertebrate anatomy.

The whole thing looks so good that I worry some viewers will think the autopsy is real. (Confusion has been stirred with less.) But T. rex Autopsy doesn’t use the same slight of hand that recent Discovery shows focused on mermaids and giant prehistoric sharks relied on. T. rex Autopsy starts with the line “Imagine if the government found the complete body of a dinosaur…”, and, over the end credits, narrator Jack Davenport explains that the tyrannosaur is a prop that took six months to build. Some suspension of disbelief is required to enjoy the show, but at least the program is forthright that such an admission ticket is required.

In a post-Walking With Dinosaurs era, when almost every program about ancient life is dominated by slavering cgi monsters, T. rex Autopsy is a refreshing approach to dinosaurs. It’s wet, it’s gross, and it’s intimate. The show required the construction and deconstruction of our favorite dinosaur at a level never before attempted. Even if some of the anatomical tidbits fly by a little too fast, you’ll want to watch just for the spectacle. You’ve never seen a dinosaur like this before.


I loved T. rex Autopsy, and if you want to know more about the show you should check out John Hutchinson’s account of what it was like being a scientific advisor on the program. But I can’t say I’m a fan of another upcoming National Geographic Channel special.

In the lead up to the release of Jurassic World, National Geographic Channel is releasing a slew of dinosaur-related programs. In addition to T. rex Autopsy, they’ll also be presenting a show called Dino Death Match. I haven’t seen it yet, but it’s centered around the so-called “Dueling Dinosaurs” – a tyrannosaur and ceratopsid found buried together.

There are a few problems with the dinosaur pair. The first, despite the hyped title, is that there’s no conclusive evidence that they actually fought each other to the death. But the larger problem is that these dinosaurs are currently in private hands and have not been formally described. They can’t be until they’re permanently reposited in a recognized scientific institution, ensuring that they will not only be cared for, but open to repeated study by experts. Privately-held fossils can all-too-easily be withdrawn from scientific scrutiny by their owners, sold into personal collections, or otherwise be cordoned off from scientists, making them effectively useless to expanding our knowledge of past life. That’s why the scientific standard, set forth by the Society of Vertebrate Paleontology, is that significant fossils should be curated in a recognized scientific institution before they are published upon.

In fact, these dinosaurs could have gone to a private collector rather than a museum. They were presented for public auction in November 2013 and failed to sell. Dino Death Match seems like the latest attempt to plump up the significance of these fossils as the owners search for a bidder willing to drop millions of dollars on the dinosaurs. Even if museums had that sort of cash, spending it on the two dinosaurs would be ill-advised – the $9 million asked for the “Dueling Dinosaurs” could fund research, fieldwork, and staff for decades at most any institution you care to name. It’s difficult to see the show as much more than another piece in the press package meant to make these dinosaurs look attractive to a buyer. In short, creating an hour long advertisement for controversial fossils held in private hands is an ethically dubious move by the National Geographic Channel.

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Please Welcome Erika Engelhaupt to Phenomena!

Erika only has eyes for you, dino (shot at the Phil Fraley studio, while on assignment for the Philadelphia Inquirer).

Today, Phenomena gets a little spookier as we welcome Erika Engelhaupt to the salon. The name of her blog says it all: In Gory Details, she’ll be bringing you tales from the darker side of science — creepy thrills, macabre reality checks, and stuff for which the term “morbid fascination” aptly applies.

Maybe it has something to do with all the time she spent tromping around in swamps while studying environmental science, earning a couple of master’s degrees and – in her words – publishing “boring science papers.” After that, Erika ditched the science papers and began writing for newspapers, triggering a metamorphosis from scientist to science journalist. Now, in addition to being our newest Pheno-type, Erika is also the online science editor for National Geographic, and will help manage the Phenomena blog network.

I’ve known Erika for a while now (she was one of my editors at Science News), and she’s always seemed so…normal? To celebrate the launch of Gory Details, I asked Erika some questions about where she’s headed.


So what’s this obsession with gory stuff?

I suspect I may have read too many Stephen King novels at a young age. My mom and I would tear them in half down the spine so we could each read half at the same time. I’ve always enjoyed reading about creepy stuff (but no scary movies—I prefer my imagined horrors over Hollywood’s versions). Combine that with a love of science, and I guess you get Gory Details.

How did Gory Details come about?

I was an editor at Science News, and one day I was sitting in my office and looked at a shelf filled with books I had reviewed for the magazine. There were titles like Blood Work, The Killer of Little Shepherds (a fantastic forensic history), and That’s Disgusting. It had never really dawned on me until that point that maybe I had a morbid fascination. Suddenly it just popped into my head—I should write a column on the dark side of science and call it Gory Details.

At the time the magazine was soliciting ideas for news columns, but mine was initially considered too gross for a column. So I had to bide my time for two years until we were launching new blogs, and I got my chance. And it turned out that other people shared my curiosity.

What do you want this blog to be about?

So many things! First, I want to really delve into forensic science, because there’s so much going on right now. We’re at this strange point where there are really amazing high-tech methods being developed to analyze crime, but mostly what police have to work with is very old-school, and actually a lot of basic forensic analyses, like hair analysis, are being questioned — is this stuff even really science?

I’m fascinated by all manner of dead things, too. That includes archaeology, and pretty much anything involving old bones. I’m a sucker for a Neanderthal story, because I love to think about how close we are to our beetle-browed cousins.

Then there is, of course, the gross beat. I ended up writing a lot of stories about pee and poop in the blog previously, and every now and then I would announce a hiatus on bodily functions stories. But then someone would come along with some fascinating thing about fecal transplants or something, and I’d be off to the races with that.

I’d also like to branch out into some other areas that people might not immediately think of as gory, but that fall into the “huh, weird” category. So robots and artificial intelligence, perception (which, trust me, is full of really strange stuff), and the dark side of human nature.  And I’m an environmental scientist by training, so I’m going to claim that environmental nasties are something we need to examine in gory detail too.

Evidence of actual past scientific endeavor. Here's Erika in grad school, studying soil microbial activity in Costa Rica.
Evidence of actual past scientific endeavor: Erika studying soil microbial activity in Costa Rica.

 So…sort of the “eww” beat?

I’m happy to claim the “Eww” beat! When Maryn McKenna joined Phenomena recently with her scare-tastic blog Germination, someone on Twitter pointed out that she was claiming the “oops” beat (since she often covers how we humans have messed up the good thing we had going with antibiotics). And they noted that Ed’s on the “Wow” beat, and Nadia, I think we decided you were the “Boom” beat, right? Or maybe “Oooh”? And if Brian’s “Rock” and Carl’s “Life,” I guess that leaves me with “Eww”!

What are some of the spookier stories you’ve uncovered so far?

Some of my favorites have been ones that pose a “scary thought” kind of question. I really delved into what would happen if a nuclear bomb went off in Washington, D.C., where I live and where sometimes the threat of an attack feels quite real. I wrote about my own odds of survival less than a mile from the White House (not terrible, actually) and how to do the math on whether to seek better shelter or stay put.

Also along those lines are questions like “What lives on us after we die?” and “What drives ‘nice’ people to aggression?

One I found chilling in a different way was a story I uncovered about police in Israel who have developed a way to get fingerprints off rocks. They want to use the technique to find and prosecute Palestinians, often kids, who throw stones at Israelis. It’s a sad reminder of all the people hurt by that conflict.

I also love finding really weird stuff in out-of-the-way corners of science. I had great fun with  the story of a researcher who set up a re-enactment of da Vinci’s painting of the Mona Lisa using toy figures and posited that the original and a studio copy may have been made as the world’s first experiment in 3-D imaging. No one knew about this guy’s work, and after I broke the story it went nuts.

I imagine you’ve got a pretty thick skin since you’re used to diving into the world of weird. Is there anything that’s too creepy, scary or gross for you to deal with?

You know, it’s funny—there’s a psychology test for how easily disgusted a person is, and I tested out dead average. I’m not especially hard to gross out. Maybe that’s part of the fun; that I have a very normal response to this stuff.

But to answer your question, I have tried to be careful about writing about gory medical conditions, because I don’t want to come across as making light of people’s very real problems. And as for what I’m personally freaked out by, it’s gotta be crocodiles. They populate my nightmares.

“I took this in Costa Rica, at a bridge where people gather and occasionally throw meat to the crocodiles,” Erika says. “Nightmares for weeks.”



How to Pick up Pliocene Takeout

[Note: This post was originally published on January 7th, 2 million years before present.]

I’m sure you know the feeling. You’ve been digging up roots and tubers for days and they’re just not hitting the spot. Something more savory would be delightful, but, like they do, lions take their share of their kills, leaving what looks like just scraps for you and your family. Well don’t despair, my hominin friend. If you know what to look for, you can turn even a practially-skeletonized carcass into a feast.

The first step is picking the right place to dine. An open grassland just won’t do. There’s no place to hide out in the open, and nothing ruins a meal like an uninvited leopard showing up to dinner. And you’ll want to avoid the haunts of bone-crunching hyenas, too. Aside from the fact that you don’t want to wind up as an appetizer for them, they usually don’t leave much behind beyond scattered, splintered bones. What use is a bone-shard toothpick if you’ve nothing to pick out of your teeth?

You’ll want to look for a large carcass in a more closed habitat. Someplace wooded and a little more shady. This is where sabercats prowl, and, when spotting leftovers, big cats are practically your sous chefs.

Sigh. Goodbye, lunch. Photo by Mariomassone, CC BY-SA 2.0.

You can pinpoint a promising carcass by the way it looks.

Hyenas disarticulate and scatter skeletons, often carrying off the heavily-muscled limbs to consume elsewhere. Not to mention that they strip almost every piece of meat from the bones in the process. A disorganized clump of bones probably won’t hold much for you. But big cats are more interested in the softest and most accessible cuts, usually starting with the hind legs and continuing on to the thorax, head, and forelimbs. The skeletons of their kills are usually left relatively intact, and, depending on the habits of the local cats, there’s usually a good deal of flesh left on the skeleton.

Don’t fret if you can only see bones at a distance. There’s still plenty of good eating on that carcass. If you’re lucky, you’ll find large pieces of flesh still attached to spots like the skull, legs, and ribs. Those are easy enough to slice off with a handy stone tool – never leave home with out some cutlery in hand – but you’re more likely to find some smaller morsels. Some hominins look down their noses and call these “scraps”, but that’s just negativity. If you can pinch a piece of horse or antelope flesh between your thumb and forefinger, that’s big enough to give you a juicy mouthful.

Consider this: even a horse leg with 10% of the original amount of meat left on it still yields 2-4 pounds of flesh. And if the same is true of the rest of the skeleton, well, you’re looking at between 2,000 and 6,000 calories of protein! Even the lower range is enough to fulfill the caloric needs of at least one of your clever Homo erectus for an entire day. And that’s not even considering the marrow held inside those bones!

Don’t believe those uber-macho hominins who say you need to run leopards and hyenas off kills in order to enjoy a steak dinner. Natural selection will likely see them off sooner rather than later. If you’re patient and don’t mind a little cat saliva, you can have a meaty “cheat day” meal to mix up the routine of tubers and water plants.

This post is based on a new Journal of Human Evolution paper by National Museum of Natural History anthropologist Briana Pobiner. Read her paper for fully fleshed-out details of how she determined how much meat some lions leave behind and what this means for the menu of our Plio-Pleistocene forebears. Top photo from here.


Pobiner, B. 2015. New actualistic data on the ecology and energetics of hominin scavenging opportunities. Journal of Human Evolution. doi: 10.1016/j.jhevol.2014.06.020

How Leopards Helped Make the Fossil Record

I have to apologize to carnivores. In an article about how to become a fossil, published last summer, I wrote that I wasn’t enamored with the idea of being deposited in the fossil record as bone scraps in carnivore dung. That’s still true, but I should have done more than make a passing joke about my fossilization preferences. There’s more to the story than scat. Carnivores have contributed greatly to literally assembling the fossil record.

From crocs to hyenas, predatory animals past have inadvertently assisted paleontologists by bringing their meals to lake bottoms, caves, and other places amenable to preservation. Worse for wear the skeletons they may be, but it’s better to have bitten bones than none at all. And among all these carnivorous accumulators, leopards have been especially helpful.

Watch any nature documentary about big cats and you’re likely to see a guarding a kill the cat has stashed up a tree. Prehistoric leopards likely did the same, but they also dragged carcasses back to caves. Lairs replete with bones are cat-created records of prehistoric fauna, including early humans, and one such Ice Age site in northeastern Spain is the focus of a new PLoS One paper by paleontologist Víctor Sauqué and colleagues.

Known as Los Rincones, the cave contains a Pleistocene mix of mammals that lived in the area prior to 12,000 years ago. From 1,443 collected fossils, the researchers counted brown bear, wolf, leopard, lynx, red deer, roe deer, Spanish ibex, Pyrenean chamois, a large bovid, and two horse species among the large mammals. From the details of those bones – including the ages of the animals that deposited them to the pattern of remains preserved – Sauqué and coauthors concluded that leopards were the primary agents creating the assemblage. To do that, though, they had to navigate some tricky aspects of the boneyard.

A breakdown of identified large mammal elements at Los Rincones. From Sauqué et al., 2014.
A breakdown of identified large mammal elements at Los Rincones. From Sauqué et al., 2014.

Looking at the representation of animal remains found in Los Rincones, brown bears might initially seem to be the most important carnivores. Their skeletons are far more complete and significantly more numerous than those of leopards, embodying a range of ages from cubs to adults. But rather than representing a predatory presence, Sauqué and colleagues argue, these aspects of the bear bones indicate that the ursids were hibernating in the cave. Maybe they chewed on bones already there, but, since bears aren’t known to take food back to lairs, their numerous bones mean that they used Los Rincones as a spot to snooze more than anything else.

A few of the cave’s bones also bear cutmarks made by humans. Was the cave a slaughterhouse used by prehistoric people? Unlikely. The cut marks and remnants of stone tools are few, and there’s no sign of sustained human presence. People may have used the cave to butcher kills on occasion, Sauqué and coauthors suggest, or the bones could have been scavenged by carnivores after humans had taken their share from carcasses. If humans stopped by the cave at all, they didn’t stay.

Given that the cave’s bones looked to be accumulated by animals, rather than washed in from the outside, this left Sauqué and colleagues with two candidates – hyenas and leopards.

Hyenas are bone hoarders, and also roamed across Spain during the last Ice Age. But they probably had little, if anything, to do with Los Rincones. For one thing, no sign of hyenas has been found in the cave so far. No scat, no bones chawed in a hyena-like fashion, no milk teeth from the pups they would have raised there. Not to mention that hyenas often tear off pieces of larger mammals to run back to their dens. A hyena-created cave assemblage would have elements from mammoths and other big beasts, which are lacking at Los Rincones.

Leopard bones found in Los Rincones. From Sauqué et al., 2014.
Leopard bones found in Los Rincones. From Sauqué et al., 2014.

Leopards are a better bet. Not only are they the second most common carnivore at the site – their bones making up a little more than 12% of the recognized fossils – but the details of the rest of the assemblage fit their modus operandi. The majority of the herbivorous animals found in the cave are juveniles of mid-sized herbivores such as the especially-prevalent Spanish ibex. These horned herbivores fit within the preferred prey range seen among leopards alive today – big enough for a good meal, but not so big as to be impossible to haul away to a secretive spot. More than that, leopards left the skeletons of the carcasses much more intact than hyenas would. Cats mainly feed on soft tissues with hyenas are capable of crunching bones down to shards.

Based on the fossil trail the cats left behind, it seems that the leopards pounced on unwary ungulates that grazed and browsed near the cave. Rather than dismember their prizes at the scene, though, the spotted felids dragged their kills back to the cave to eat in relative safety, littering the lair with skeletal leftovers. The cats didn’t stay there permanently – brown bears and humans left their mark on the assemblage as they took their turns in Los Rincones – but leopards were responsible for hoarding most of the fossil riches paleontologists now pick over. Thanks, cats.


Sauqué, V., Rabal-Garcés, R., Sola-Almagro, C., Cuenca-Bescós, G. 2014. Bone accumulation by leopards in the Late Pleistocene in the Moncayo Massif (Zaragoza, NE Spain). PLoS ONE. 9, 3: e92144. doi:10.1371/journal.pone.0092144

Dental Damage Complicates the Fate of America’s Greatest Fossil Cats

There are no sabercats alive today. The clouded leopards of Asia come close, but even their long canines look dainty in comparison to the extended teeth of the last true sabertooths. And even though humans undoubtedly saw and lived alongside sabercats, no one recorded how the big cats fed or why they died out. The hyper-fanged felids have only been extinct for about 10,000 years, yet their biology and disappearance remain oft-debated mysteries. A new study of microscopic damage preserved on sabercat teeth only makes their lives and ultimate extinction all the more perplexing.

Smilodon fatalis is practically synonymous with California’s La Brea asphalt seeps. The tar has yielded more remains of Smilodon here than anywhere else in the world, and the abundant cat was just one species in a wider cast of carnivores and now missing-megafauna. Indeed, while Smilodon was an imposing predator, its rarer neighbor the North American lion – Panthera atrox – was a bit larger.

Both cats died out around the same time. Their demise has traditionally been tied to the disappearance of the mammoths, mastodons, giant ground sloths, and other megamammals. Climate change, human hunting, or a combination of the two drove North America’s Ice Age giants into oblivion. Predators who relied on massive amounts of mammoth meat followed suit.

Previous studies of La Brea’s cats seemed to confirm this hypothesis. Broken Smilodon and American lion teeth hinted that these cats were cracking open the bones of their prey to make the most of relatively rare kills – unusual behavior for cats, who typically favor soft-tissue. Chipped canines and damaged teeth indicated that the predators were struggling towards the end of the Pleistocene, and at some point there was simply not enough meat to go around.

But patterns of microscopic wear tell a different story. Today in PLoS One, Vanderbilt University paleontologist Larisa DeSantis and colleagues report that both Smilodon and the American lion were not quite so stressed as earlier studies supposed. By comparing the dental topography of scratches and pits on the molar teeth of extinct cats with the micro-damage on the teeth of modern cheetahs, lions, and spotted hyenas – carnivores with known dietary preferences – the researchers were able to outline the feeding habits of the sabercat and American lion. The results contradict what paleontologists have often thought about these cats.


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Did Grey Seals Mutilate Two Harbour Porpoises?

Here’s the face of a grey seal. Aw. Doesn’t it look adorable? Remember, however, that seals evolved from bear-like ancestors and are part of the (mostly) flesh-eating group of mammals called carnivorans. If you look inside its mouth, you’ll find strong canine teeth. And Jan Haelters from the royal Belgian Institute of Natural Sciences thinks that those teeth did this to a harbour porpoise:


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Leopard seals suck

“It is an awe-inspiring experience to be faced with a 3-metre-long, 500 kilogram predator, the size of a racehorse, as it launches itself out of the water and slides on its belly for a couple of seconds, coming to a halt barely a metre away from where I stood, without any barrier between me and it.”

That was how Erich Fitzgerald met Sabine the leopard seal.

Leopard seals are like the lions of the Antarctic. They are huge, powerful predators, known for their brutal killing strategy. They bite penguins and seal pups with their big canines, and thrash them onto the surface of the water to flay and dismember their prey.

But Fitzgerald, David Hocking and Alistair Evans have shown that these predators can take smaller prey in a very different way. They suck krill and small fish into their mouths and sieve them in the manner of whales, by passing their mouthfuls of water through tightly interlocking teeth. It’s astonishing behaviour that allows them to dine from the top and bottom of the food chain. As Fitzgerald told me: “This is equivalent to a lion hunting down zebras, but also regularly feasting on ants or termites.

I’ve written about the story for Nature News. Head over there for the full details.

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One way to skin a cat – same genes behind blotches of tabbies and king cheetahs

The cheetah’s spots look like the work of a skilled artist, who has delicately dabbed dots of ink upon the animal’s coat. By contrast, the king cheetah – a rare breed from southern Africa – looks like the same artist had a bad day and knocked the whole ink pot over. With thick stripes running down its back, and disorderly blotches over the rest of its body, the king cheetah looks so unusual that it was originally considered a separate species. Its true nature as a mutant breed was finally confirmed in 1981 when two captive spotted females each gave birth to a king.

Two teams of scientists, led by Greg Barsh from the HudsonAlpha Institute for Biotechnology and Stanford University, and Stephen O’Brien from the Frederick National Laboratory for Cancer Research have discovered the gene behind the king cheetah’s ink-stains. And it’s the same gene that turns a mackerel-striped tabby cat into a blotched “classic” one.

Back in 2010, Eduardo Eizirik, one of O’Brien’s team, found a small region of DNA that seemed to control the different markings in mackerel and blotched tabbies. But, we only have a rough draft of the cat genome, they couldn’t identify any specific genes within the area. The study caught the attention of Barsh, who had long been interested in understanding how cats get their patterns, from tiger stripes to leopard rosettes. The two teams started working together.


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Revising the polar bear’s evolutionary past… again

Earlier this year, I wrote about a new study showing that polar bears split off from brown bears around 600,000 years ago – already making them four times older than previously thought. Now, a new study pushes the date of that split back even further, to between 4 and 5 million years ago. The exact date is probably going to shift again in the future, and if anything, it’s the least interesting bit of the new paper.

Webb Miller, Stephan Schuster and Charlotte Lindqvist have taken a whirlwind look at the history of the polar bear. For a start, they sequenced its genome – that detail would be the centrepiece of other papers, but gets mentioned halfway through this one. They started looking at the genetic changes that have made polar bears lords of the Arctic, and they reconstructed the bears’ population history across the many climate upheavals it must have lived through. Finally, they found evidence that polar bears carry a lot of brown bear DNA in their genome (and vice versa) – a sure sign that the two species repeatedly bred with each other after diverging, in much the same way that our ancestors had sex with Neanderthals and other ancient humans.

I’ve written about the study for The Scientist. Head over there for the full story.

Photo by Alan Wilson

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Polar bear origins revised – they’re older and more distinct than we thought

Doesn’t look a day older than 602,000

It looked like we had the polar bear’s origin story nailed down. Genetic studies suggested that between 111 and 166 thousand years ago, a group of brown bears, possibly from Ireland, split off from their kin. In a blink of geological time, they adapted to the cold of the Arctic, and became the polar bears we know and worry about. Fossils supported this story: the oldest polar bear bone is between 110 and 130 thousand years old.

But according to Frank Hailer at the Biodiversity and Climate Research Centre in Frankfurt, this story is wrong in two important ways. First, the polar bear aren’t just a branch of the brown bear family tree. They’re a separate lineage in their own right. Second, they around four times older than anyone had thought, arising around 600 thousand years ago.

If this new vision is right, the bear’s journey to polar dominance wasn’t a speedy sprint, but a more leisurely stroll. As a species, polar bears have seen many ice ages. Rather than being a symbol of extraordinarily fast evolution, they’ve actually had plenty of time to adapt to life in the freezer.


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In run-up to Easter, fasting Ethiopians force hyenas to kill donkeys

It’s Easter. For some of people, this means they can take up all the vices they gave up for Lent, and binge on chocolate till they feel sick. For the hyenas of northern Ethiopia, it means it’s time to stop hunting donkeys.

Spotted hyenas are unfussy eaters and incredible opportunists. They can feast on rotting meat, anthrax-infected corpses, garbage and dung. They digest their food so completely that their droppings tend to consist of hair, hooves, and white powder made from broken-down bones. Unsurprisingly, they do rather well near urban environments, where humans provide them with a bonanza of scraps, leftovers, and livestock. The hyenas of northern Ethiopia get almost all of their food by scavenging on such sources.

Local humans tolerate the hyenas, which are affectionately known as “municipal workers”. The animals clean the waste from butchers, households, and even the local veterinary college. They’re seen and heard almost every night, and they almost never attack humans. Instead, they have come to depend on the Ethiopians for their food.

But that changes in the run-up to Easter. For 55 days, the local Orthodox Christians go through a period of fasting. Meat goes off the menu, and few animals are slaughtered. This lack of demand creates supply problems for the hyenas. Gidey Yirga from Mekelle University in Ethiopia has found that they sate their hunger by hunting instead.


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A lack of taste – how dolphins, cats and other meat-eaters lost their sweet tooth

Imagine a world without sweetness, where you couldn’t taste the sugary rapture of cakes, ice cream or candy. This is what it’s like to be a cat. Our feline friends carry broken versions of the genes that build sugar detectors on the tongue. As such, they’re completely oblivious to the taste of sweet things.

So are Asian otters. And spotted hyenas. Sea lions and dolphins too. In fact, Peihua Jiang from the University of Zurich has found that a wide variety of meat-eating animals can’t taste sugars. The genomes of these carnivores are wastelands of broken taste genes.