Giving birth though a soda straw: ouch!!

One of the most mysterious and bizarre characteristics of the spotted hyena is the heavily masculinized genitalia of the female. Here you can see adult female Gucchi (wearing the radio collar) investigating the genitalia of adult female Carter (who has her butt toward the camera and her tail raised) during a greeting ceremony at the den (that's Gucchi's cub, Alfredo, scratching himself while his mom greets). Notice that Carter has a male-like pseudoscrotum and a male-like phallus. It is not known why female spotted hyenas sport such unusual genitalia. However, one of the most amazing things about all this, in my opinion, is that the female is obliged to give birth through that narrow tube. Cubs weigh just over two pounds at birth, so imagine introducing a baby that size to the world via that route. It has GOT to hurt! In fact, the female's pseudopenis tears when she bears her first litter, and this natural episiotomy leaves a neat strip of pink scar tissue on the posterior surface (see blow-up). Thus, even if her first cubs die before we can ever see them, we can tell that a young adult female has given birth based on the presence of that scar tissue.

How low can your belly go?

A hungry adult spotted hyena can consume a LOT of food in a single meal. An adult hyena is shown in the top photo before consuming a meal. An adult female typically weighs about 65 kg (roughly 145 lbs). Although average meal size for spotted hyenas varies across Africa from 0.2 kg to 9 kg, an individual hyena can consume approximately 18 kg of meat and bone in an hour. That's 40 lbs of food, folks. Imagine how you'd feel if you had just consumed 160 Quarter Pounders at one sitting. A bit bloated, right? Well the bottom photo here shows you what a spotted hyena looks like under the same circumstances. Notice that she's still going strong, continuing to feed even though her belly is almost touching the ground. Now you can also imagine how hard it is to determine when a female spotted hyena is pregnant based on her appearance; with her belly size going up and down this much during feeding and fasting, it's very tough to detect the presence of a litter that, at most, will weigh only about 3 kg!

Why eat so much at a single meal that you can barely waddle away afterward? Well, if you're a female spotted hyena, you do this because your ability to produce and support babies is strictly determined by how much food you consume. And you never know when or where your next meal might be coming from. If you were dining at McDonald's and knew you might not be able to eat again for several days, I bet you'd probably try to jam in an extra Quarter Pounders or two yourself.

My, what big teeth you have...

A hyena's mouth is a pretty intimidating sight. But, as long as you're not a tasty ungulate, it's also a fascinating one.

Surprisingly, it's not those deadly-sharp canines (those dagger-like teeth in front) that enable hyenas to do so much damage. Instead, it's the rather innocuous-looking premolars, located farther back along the jaws, that give hyenas their bone-cracking abilities.

Hyenas will carefully position a bone on one side of their mouth and bite down. Hard. Really hard.


From measuring hyenas' teeth, we can gather all sorts of information about them. We can tell an individual's rank (since low-rankers must crack far more bone than high-rankers, their premolars are much more worn), we can tell an individual's age (older animals' teeth are more worn than younger animals), and whether a hyena is "right-sided" or "left-sided" (just like we prefer to use one hand to write or to throw a ball, hyenas tend to use one side of their mouth more often to crack bone).

Now that I think about it, maybe that's why our hyenas steal soap...it gives their jaws a nice rest from all that work.

One-eyed wonder

About a month ago, we noticed that Quark, a 5-month old Happy Zebra cub, had a very swollen right eye. The swelling has finally gone down, and now we realize the eye isn’t just damaged…it’s completely gone.


I know what you’re thinking: are you guys really geeky enough to name a lineage of hyenas after subatomic particles?

Um, yes we are. But perhaps you’re also thinking: yikes…what’s it like being a hyena with only one eye?

Hyenas have what we call “binocular vision,” meaning that their vision is a result of two overlapping images – one from each eye – that the brain puts together. This allows for several fantastic advantages, such as depth perception and increased detection. Animals such as predators (which rely on particular visual cues to hunt moving prey) and primates (which need to find and select particular fruits from the surrounding vegetation) often have binocular vision. Their eyes are usually placed closely together on the head and oriented forward.

Animals with “monocular vision” (like the rhino below) have eyes that are on opposite sides of their head, rather than in front. These animals use each eye separately, but the big advantage here is an increased field of view – sometimes nearly 360 degrees. If you’re a tasty Mara antelope and the biggest problem in your life is some scary carnivore creeping up on you while you’re chowing down on grass, you’re going to want to see as much as the world around you as possible. For most prey species, accuracy and depth perception probably aren’t quite as important as knowing what's around you at all times.


OK, enough biology lessons. The point is that, since hyenas need abilities such as depth perception, poor one-eyed Quark is probably at a real disadvantage. Try closing one eye and trying to play darts (first, please make sure nobody else is within striking distance)…it’s not easy. Now, imagine losing an eye and trying to catch a gazelle zipping around at 50 miles per hour.

But, Quark still has one good eye, and we aren’t counting her out quite yet. After all, our resident rebel Moss is likely blind in one eye, and she continues to kick some serious butt. Plus, Quark is pretty high-ranking, so, in theory, she doesn’t need to hunt at all to survive…she just needs to take advantage of others’ success. In any case, life probably isn't going to be easy for Quark.

What a difference a nipple makes

We've mentioned several times that sibling rivalry in spotted hyenas is fierce. You might recall from my long-ago post on the dominance hierarchy that if a female has two cubs, one becomes dominant almost immediately, and reaps the benefits of this. It has easier access to the mother's milk, gets cuddled while nursing, and develops faster. In fact, we think that one of our older females, Moon Pie, actually has a bum nipple—all females have two teats—so in this case the difference is especially drastic. When Moon Pie has twins, the dominant cub tends to develop at a much faster rate than its subordinate sibling.

Anyway, here are a couple photos that highlight some of these differences. Remember Falafel, who had newborns back at the end of July? (She was the one who drooled all over one of them.) Here's a chance for you to check in on the progress of her cubs, Tilt and Jordache. It is difficult to see the difference in size because they aren't in the same photo, but you are able to see the difference in development. Notice how Tilt, the dominant cub (top photo), is already getting its spots, whereas Jordache, the subordinate cub (bottom photo), is still mostly black:




But it gets better. Perhaps you also recall that there's not only a difference between dominant and subordinate siblings...there's also a difference between high-ranking and low-ranking cubs. High-ranking cubs develop much more quickly than their low-ranking counterparts, because their moms have better access to food. Here's a picture of two cubs, Jordache (left) and Monopoly (right), that were born within two days of one another, and look at the tremendous size difference between them:



Monopoly is the granddaughter of Murphy, our alpha female, whereas Jordache is the granddaughter of a low-ranking female in a different matriline. You can see we're not messing around when we say this whole rank thing is pretty important. The last photo is also of Monopoly, and I'm including it just to give you a better idea of how quickly Monopoly's spots have come in compared to those of Tilt or Jordache.

Hyena Myth #1: Busted

Let’s face it, hyenas are weird. And, while their bizarre qualities are what we scientists can’t get enough of, they’re also the reason that hyenas have been forever loathed and misunderstood. There are more myths surrounding hyenas then I can count, but we’ll start with one of the strangest and most common....

Yesterday, a safari guide stopped us on the road. He said, in a hushed tone (like many guides, he liked to pretend he knew everything and didn’t want his clients to hear him admitting uncertainty), “Is it true that in hyenas, males and females are, you know…one?” It wasn’t the first time I’d heard this question, and I’m sure it won’t be the last.

While males and females are not, in fact, “one,” hyenas do have a definite physical peculiarity: the two sexes have nearly indistinguishable genitals. That’s right: female hyenas have “pseudopenises” - completely capable of erections – as well as “pseudoscrotums” made of fatty tissue. Don’t say I didn’t warn you…I told you they were weird.

In fact, if I didn’t know any better, I’d buy into this whole male=female thing too. Check out the hyena below…that, dear readers, is a female hyena in all her male-mimicking glory.


Imagine seeing that hyena nursing a cub or – stranger still – giving birth. That’s why, for millennia, people have thought that hyenas had both male and female organs, a biological phenomenon called hermaphrodism. This sexual ambiguity, popularized by writers from Ovid to Hemingway, has made hyenas the subject of confusion, fear, and mistrust.

While hermaphrodism may seem like material for freak shows and science fiction novels, it’s actually somewhat common in the animal world. Picture this (I liked Leslie's hypothetical "Carl" story, so here goes): you’re a female sea cucumber that lives on the ocean floor and rarely comes into contact with another sea cucumber. But, you'd really like to fulfill your biological destiny to mate before you die. You may wait days, weeks, or months to see another sea cucumber…so let’s hope it’s a male! OR you could be a hermaphrodite with the potential to be both male and female…that way, no matter who you run into, you’ll be able to fill the ocean with lots of adorable baby sea cucumbers.

However, hyenas certainly aren’t solitary, and they encounter members of the opposite sex dozens of times a day, so hermaphrodism wouldn’t be a real advantage here. Instead - despite all appearances - hyenas follow the standard mammalian pattern of having two distinct sexes: males and females. While scientists as far back as Aristotle have tried to clear up the confusion, their rational arguments have been drowned out by images of female hyenas’ uncanny “maleness.”

Of course, if you’re even slightly scientifically-minded, this brings up the obvious question: why do females have pseudopenises? Well, we're still working on ironing out the details of that one. If you've got a definitive answer, let me know, and I'll have a PhD in the bag.

It's only natural

When I posted the photo of the obese hyena on Halloween, an astute reader posed the question of if she might get diabetes from being so fat. An excellent question!

The short answer is no, probably not. First of all, hyenas can go from "fat" to "normal" and back pretty quickly...they are capable of gaining an astounding 20kg in a single meal (that's 44 lbs. for those not metrically-minded). To give you some perspective (if you still need any after reading "44 lbs."), that's about 130 hamburgers, and at least three times as much as I can eat at Thanksgiving. Obviously that's not all retained as fat, although after such a gorging they will stay fat for days (Navajo, the hyena in the picture, is just now starting to return to her normal, albeit heavy, weight).

But back to the question—can hyenas get diabetes from being so fat, even if they're only fat sometimes? Well, I'm sure it's possible, but the truth is that most wild animals don't contract diseases like diabetes or cancer. That's because the selection pressures (yes, selection as in natural selection) are too strong. In other words, if there were a hyena that got diabetes from obesity—let's call him Carl—it would probably be because Carl had a genetic mutation predisposing him to the disease. Well, Carl certainly wouldn't fare very well against the other hyenas in The Game of Life, since he would be too busy trying not to keel over in a diabetic coma. Carl probably wouldn't produce as many offspring as other hyenas. In fact, maybe Carl would die before he had a chance to produce any. Bummer for Diabetic Carl, but less of a bummer for the hyena population's next generation, because now those genes for diabetes have gone with Carl, without getting passed on. In other words, they've been selected out. This is also why animals don't typically get diseases like cancer.

Okay, so why do we get cancer? By now you have probably caught on and guessed, because if you're reading a blog about hyenas you're most likely in touch with your Inner Science Nerd, but I'll elaborate nonetheless.

Humans are subject to natural selection just like any other species, but we have a special knack for relaxing (weakening) it. We have developed a million different medicines, medical treatments, and other life-saving and life-prolonging tactics to help us overcome things that would have surely done us in a couple hundred years ago. Think about it—a few hundred years ago, if you got the flu, things didn't look good for you. If you had a difficult childbirth, you and your child were in serious danger. And if your body stopped producing insulin, well, you were pretty much out of luck. It's therefore no surprise that life expectancies were half what they are today.

Today, thanks to technological advances, we're able to look natural selection in the eye and say "Pfff! Bite me!" Okay, it's not exactly like that, but the selection that operates on us now is so weak that it can be almost impossible to detect. I've had the flu, as have most of you, and I'm confident that if I can't pop a baby out naturally, my obstetrician can come up with some kind of a solution. And although diabetes is a very serious health condition, it is now something that people can commonly live with if they take proper precautions (and live in a country that doesn't mind insuring all its citizens...whoops, sorry, slip of the tongue). As for cancer, most wild animals—like humans not that long ago—never live long enough for cancer to get them. Those that do get it die pretty quickly, so the ones that are less likely to get cancer are the lucky ones who get to pass on their genes.

I don't mean to imply that natural selection doesn't act on humans at all any more, because it certainly does. It can just be a lot slower and a lot more subtle than it used to be. This is why human overpopulation is such a problem—we've removed many of the natural population controls. But that's a story for another day.

**Special thanks to Andrew S. Flies for his input on this matter.

Ahh, the miracle of life

It sounds so pleasant and innocuous when one describes giving birth as a “miracle,” but from what I can gather, from the point of view of the mother it’s more along the lines of “yeah, it’s a miracle all right—it’s a miracle that I survived this hell and thank god it’s over.” Full disclosure to readers: I have never given birth. Despite my own “nulliparity” (from the Latin, “nullus”=none + “parere”=bear children), birth has been on my mind a lot lately, mostly because my best friend, Perrin, is about to pop out her first child any day now (shameless plug: not just any child, but my very own goddaughter).

Hyena mamas carry their young around in their bellies for 110 days before sending them out into the world. I know what all you mamas are thinking—“wimps! I carried my child around for two and a half times that long!” Well, that may be true, but you should know that elephant mamas have you beat; their pregnancies last 22 months. Maybe you need to read that one more time to really let it sink in: that’s right, in the time it takes an elephant mama to make ONE baby, you could have made TWO. Betcha feel like kind of a slacker now, don’t you?

Anyway, I digress (what else is new). The point of this story is that I saw my very first live birth the other day. It was a topi mama, and she was just standing in the middle of a field. At first it looked like she was pooping, but upon closer inspection we saw that she was actually about to give birth to a calf. I took video of the birth itself, which I can't post here unfortunately, so thanks to Andy for the first photo.

It was pretty amazing, mostly because of how quickly it happened. Her entire labor lasted less than two minutes…the calf just slid right on out like it was popping out of the bottom of a water slide. It was covered in amniotic fluid and was very endearingly confused. Interestingly, though, the mama topi seemed equally confused. She had a look that said, “I don’t know what just happened, but I REALLY didn’t like it. By the way, did anyone notice that some crazy alien just popped out of my butt??” In fact, after the birth was over, she wandered away from her newborn calf and stood with some other mamas that had more well-established calves (i.e. at least a day or two old—see last photo) and just stared in the direction of her calf, stopping occasionally to graze. We had to agree with her that those clean, fuzzy calves looked a lot cuter and a lot more inviting than her own messy one, but that didn’t stop us from shouting (softly, inside the car), “For crying out loud, stop eating grass and go tend to your bleeping baby!!!”

We watched from afar for a little while as the mother wandered farther away from the spot where her calf lay. It had started to lick itself clean and had made a couple attempts at standing up, although to no avail. However, during the time we watched it, it did make solid progress, leaving us optimistic that it would stand up and its mother would notice it and remember, “Oh, wait a minute, that’s mine and I’m supposed to take care of it,” which is entirely possible. Well, actually, everyone’s definition of “optimistic” is different. Audrey and I, Future-Mothers-of-America, were optimistic that the mama would retrieve it and the topi calf would have a happy ending. Andy was optimistic that she would forget all about it and a bunch of hungry hyenas would stumble upon it and have a jolly good time arguing over who got the choice cuts. We left before any of our versions could be spoiled by something as bothersome as the truth.

So today’s life lesson is just for Perrin: when the time comes for you to have your baby, try to stay focused. Yes, I hope for your sake the process is as quick as it was for the topi. But I hope for your baby’s sake that you don’t become forgetful and sidetracked and wander away from her to check out the hospital’s cafeteria.

Bone crushers

I mentioned last week that hyenas have a trick up their sleeve that allows them to take advantage of a food source that is inaccessible to most animals. A few people posted comments right away and hit the nail on the head. Hyenas are actually capable of breaking bones into smaller pieces and eating them. They accomplish this by gripping the bone between their teeth and the then biting down with immense amount of force. After splitting the bone into smaller fragments, they simply gulp down the chunks of bone.

The advantage of eating bones is more obvious during periods when prey animals are scarce. Being able to crack open, swallow and digest bones gives hyenas access to nutrients such as calcium and phosphorus. I would consider this similar to digging to the bottom of the pantry or freezer when I haven't been to the grocery store for a long time. I am not going to find my favorite food in either place, but I will find something to eat in one of those places. Mothers nursing cubs may eat bones to get large amounts of calcium for milk production.

A couple of interesting side notes on the diet of a spotted hyena. Spotted hyenas get around 95% of their annual food intake from fresh ungulate kills. Eating bones can be an important supplement to a healthy diet, but eating fresh meat is of paramount importance. Reports exist of hyenas cracking and eating bones as large as giraffe femurs.In the photo below, James is holding three giraffe leg bones for perspective on the size of the bones. James is about five feet and nine inches tall, so that should give you some idea about the size of these bones and the strength of hyena jaws.

Most hyenas favor cracking bones on either the right or left side of their mouth. Instead of being right or left-handed, they are right or left-mouthed. Many animals worldwide exhibit some form of favoritism for one side over the other. There is only one other animal to my knowledge that regularly breaks open bones to eat the marrow, and that is the Lammergeier, also know as the bearded vulture. This vulture picks up bones in its mouth and flies into the sky. They then release the bones and drop them on rocks with the hope of breaking open the bone. It may take several tries before the bone actually breaks open, if it does at all. Much less efficient than the hyena method of using their massive jaw muscles to break open the bones

An anatomy lesson?

Here's a baffling scene...


Skeletons in the Mara are never this intact; hungry carnivores usually scatter bones over a pretty large area by the time they've consumed a kill. If I didn't know better, I'd think this poor wildebeest bit the dust while sunbathing or attempting to make a snow angel.

But I don't think wildebeest lust after a golden tan, and it's way too warm here for snow, so I'm pretty sure someone's tampered with the scene of the crime.

My best guess? Someone decided to use what they learned in high school anatomy and put this skeleton back together. If you've got another explanation (realistic or entertaining) for this perfect specimen, feel free to share...

Hyena paws and teeth

As you can see from the picture to the left, hyena paws are pretty massive (...although in the interest of full disclosure, I do have freakishly small hands).

Also, Kate wasn't kidding when she said hyenas have clean teeth—check out these pearly whites. As she mentioned, that's probably from all the bone they eat and chew.

Compare them to the teeth of the male lion below—lions don't eat much bone at all, and this guy's teeth are noticeably more yellow because of it.

The Dominance Hierarchy

One of the major reasons that we find spotted hyenas so fascinating is their social complexity. Hyenas operate under a linear dominance hierarchy that is extremely strict: no two hyenas share a rank, and it’s very clear who is dominant to whom (to them and to us). When a cub is born, it inherits a rank immediately below its mother, making it dominant to all its older siblings. Females will retain this rank throughout their entire lives, although how close this rank is to the top will decrease as more higher-ranking cubs are born (or increase as higher-ranking adults die). Males have a slightly shoddier deal, as is usually the case in this species. When a male is born, he inherits the rank immediately under his mother, just like a female cub. He keeps this rank for the first couple years of his life, while he’s still in his birth (or “natal”) clan. But once he reaches sexual maturity, he needs to disperse to another clan, because females from his natal clan won’t mate with him (high probability of incest—gross). So each male immigrates to a new clan at around age 2, and enters this new clan at the very bottom of the pecking order. He’s below all adult females, all cubs, and even below all the other adult males who have immigrated to this new clan. The only hyenas to whom he will be dominant are future immigrant males. This must be an especially tough blow to the ego to the son of an alpha female...

The first take-home lesson is that all adult female spotted hyenas are dominant to all adult males, because all adult males in a clan are immigrants. The females will be the first ones to point this out to you when you’re watching them—they are constantly putting the males in their place by being aggressive toward them or just ignoring them. The males, for their part, act the role—they tend to tiptoe around females, keeping their distance and acting very submissively.

The second take-home lesson is that when we say this hierarchy is “strict,” we mean STRICT. It dictates everything. Yesterday we saw one mother approach a den hole to try to nurse her cub, and when a higher-ranking mother (whose cub was in the same hole) saw this, she immediately walked over and snapped at the first mother, displacing her in the hole. After the first mother backed off submissively, the dominant mother walked away—she didn’t even want to nurse at that moment, she just wanted to make it perfectly clear that it was HER hole at that time. When the submissive mother made a move to approach the hole again, the dominant mother lunged at her, decisively ending the conflict. Eventually, they both lay down a couple feet from the hole, just staring at it.

Likewise, when the hyenas have killed a prey animal, such as a wildebeest, the highest ranking females and their offspring get to eat first. They are then followed by lower-ranking females/offspring, and finally by the adult males, who often stand near the kill looking longingly (and hungrily) at the carcass as all the choice cuts are devoured by their superiors. By the time these immigrant males get access, what remains is often just the skeleton—good thing hyenas can digest bone (more about that another day)!

What can be especially heartbreaking is that these adult males do much of the leg work (pun intended) when it comes to the hunting—and yes, hyenas hunt about 95% of their food—they don’t scavenge, as many mistakenly believe. Last summer we saw one male chase down a Thompson’s gazelle, eventually killing it. He had only taken a few bites when his higher-ranking brother came along, marched right up, and swiped the carcass. Because of the strict hierarchy, there was nothing the lower-ranking brother could do except watch as his brother ate the entire gazelle.

But it gets worse. Still hungry, this male proceeded to get himself ANOTHER meal, this time chasing down a juvenile gazelle (hunting is exhausting, so this is no small feat). Just as before, within seconds of biting into it, his brother showed up on the scene. He waddled over—his enormous belly, already full of the first gazelle, was definitely slowing him down—and promptly stole and ate this meal, too. You can imagine the torrent of expletives we let out as we watched this unfair sequence of events unfold. However, to the hyenas, it is more than fair, because everyone knows the rules, and everyone plays by them.

Important life lesson: if you’re low-ranking and you’re hankering for filet mignon, try to kill your prey in private, and then eat very, very quickly.

Up next: meet our alpha female, Murphy

Dominant and Subordinate Cubs

Spotted hyena cubs are usually born in pairs, although singletons and triplets are not unheard of. One cub will immediately assert itself as the dominant cub, and if the cubs are of different sexes, this is usually the female. This dominant cub—which will remain dominant to its sibling for the rest of its life—enjoys many privileges. One particularly notable privilege that manifests early in life is that the dominant cub gets to nurse “in the preferred position.” An adult female has two teats, and the cub nursing in the preferred position lies closer to her head. The mother will often drape her front paw over this dominant cub, and even groom it as it nurses. The subordinate cub is relegated to the back, lying either between the mother’s hind legs or behind her entirely. Unfortunately for the subordinate cub, the benefits of nursing in the preferred position extend beyond cuddles and a bath: the dominant cub is often able to limit the subordinate cub's access to the teats. The result of this disparity is that the dominant cub grows more quickly than the subordinate cub—a significant difference when trying to survive in the savannah.

Important life lesson: try to be the dominant cub.

Photo: Pictured above are Ursa, an adult female, and her two cubs, Muffin and Macaroon (Ursa's lineage theme is “things found in a bakery”). You can see Muffin, the dominant cub, with its back to the camera, Ursa’s front leg wrapped around it. The subordinate cub, Macaroon, is that dark lump in the back under Ursa’s hind leg.