Monday, April 10, 2017

Cute Enough to Eat

Warning: This blog post contains images and videos that some readers may find disturbing.

If you read the most recent Serena Cub Update, you already know that Happy Zebra Clan hyenas recently stumped the hyena researchers by disappearing into the tall grass and taking all the little ones with them. Mike and I spent weeks combing over their territory to no avail. On March 17, our favorite hyena cub, Quack, decided to lend us a helping hand. While oohing and ahhing over a honey badger, Mike and I spotted a hyena cub's head bobbing through the tall grass. While following Quack's fluffy little noggin through the sea of grass, we spotted a small herd of elephants throwing a tantrum. We left Quack to go and investigate.

When we got closer to the elephants, we were shocked to see five hyenas hunkered down in the grass at their feet! Little did we know, we had just stumbled across Happy Zebra's new den! The elephants approached to just meters from the hyenas and their cubs, who held their ground. The elephants flapped their ears angrily, trumpeted, and ripped apart one of the bushes covering the den holes. Eventually, the elephants turned their attention elsewhere and left the hyenas unscathed.

We thought it only appropriate to name this den "Angry Ele Den."

An elephant rips branches off of a bush and flings them over its head. The brave and patient hyenas lie in the grass, mere meters away from the angry eles' giant feet.
Over the next two weeks at Angry Ele Den, more and more cubs poured in until the den scene was hopping once again. The "big kids" (Quack, Skeptic, Cosmos), the "itty bitties" (The Kraken, Chupacabra, Caribou Lou, Jungle Juice, and The Show Must Go On), and tiny black cubs (including King Ghidorah and Drogon) were all reunited once more.

On April first, Angry Ele Den was as busy as ever! Lance and Claymore, daughters of the matriarch, babysit the little cuties.

When we showed up to Angry Ele Den on April first, it was a peaceful evening. The sunset was beautiful, a cool breeze was blowing, and the hyenas were all healthy and happy.

In the blink of an eye, that changed.

With no warning, Claymore leapt to her feet and charged into the crowd of tiny cubs, sending them scattering. She locked onto one tiny cub in particular, who giggled and tried to dart into a den hole, but it wasn't fast enough. Before we knew what was happening, Claymore lifted the cub into the air by its neck -- CRACK -- and then dropped it into a patch of grass. Everything went quiet again.

Stunned, we waited for the cub to emerge from behind the grass, but it didn't. We moved in for a closer look, only to find its limp, lifeless body.

Claymore had just killed a cub.

Mere moments after Claymore snaps the neck of a small cub, The Kraken, drags the cub's carcass across the den complex. Chupacabra, Caribou Lou, and Jungle Juice join in the excitement, blatantly ignoring Lance's protests. 

We had previously been warned by graduate student Kevin McCormick that Happy Zebra Clan was known for killing and eating cubs. Claymore, in particular, is a notorious cub killer. "Drunk with power," graduate student Kenna Lehmann jokingly described Claymore's violent behavior. However, infanticide is not a rare occurrence among spotted hyenas. In fact, it may account for a substantial proportion of mortality in cubs up to 3 months of age. Even captive hyenas have been known to kill one another's cubs!

Immediately following Claymore's sudden violent outburst, Lance began to show obvious signs of distress. She ran over, desperately groaning over the cub's limp body. As the cubs dragged the body around the den, treating it like a toy, Lance followed them helplessly. The cubs ignored her and continued to clumsily drag around -- and trip over -- the body, ripping it apart within minutes.

The cubs didn't waste any time devouring their younger denmate.
Within minutes, they tore open the dead cub's abdomen
and set to work slurping out those delicious intestines.

Although this cub had distinct spots, we were unable to identify it. All of the known spotty cubs were accounted for, so Mike and I concluded that this little fellow must have been new to Angry Ele Den. This isn't surprising; a previous study (White, 2005) found that infanticide often occurs within three days of a cub's arrival at the communal den.

So who could this cub have been? Judging by Lance's distress, she was either a very concerned citizen or, we suspect, the mother of the now deceased cub.

Lance is the youngest daughter of Pike (the matriarch), making her the second-highest ranking hyena in Happy Zebra Clan. Claymore, Lance's older sister, is the fifth-highest ranking hyena in the clan. If this really was Lance's cub (which we cannot confirm at this time), that would mean that Claymore knowingly killed her own niece or nephew and broke rank! Is this even possible?

Who would have known the intestines would be such a hit?

Not only is this behavior possible, but it has been observed many times. Infanticide occurs both between and within clans, as well as between close relatives. Full sisters sometimes kill each other's cubs! Equally astonishing, this behavior seems to occur irrespective of rank.

Why would an unprovoked hyena kill a member of its own clan? Clanmates need each other to defend food against lions, defend territory against neighboring clans, and communally rear offspring. This is why aggressions between clanmates are usually gentle and do not result in injury.

Furthermore, why would a hyena kill such a close relative? This excludes her from any inclusive fitness benefits from that cub's success!

The Happy Zebra Cubs didn't bat an eye at the cannibalization of their former playmate.
White (2005) suggested that this counterintuitive behavior can be explained by the Local Resource Competition Hypothesis. In a nutshell, sometimes, it is more advantageous to remove a future competitor than to tolerate them... even if they are a close relative. This has been reported in other species of social carnivore as well!

Claymore carries the cub's half-eaten body as she runs in circles around the den, with Lance hot on her heels.
There are still many questions surrounding this strange incident, but one thing is certain:
Happy Zebra cubs should sleep with one eye open.

As daylight faded, Claymore claimed the now-mangled carcass of her victim.
Although Lance chased her, Claymore refused to surrender her evening snack.


1) White, P. A. (2005). Maternal rank is not correlated with cub survival in the spotted hyena, 
Crocuta crocuta. Behavioral Ecology, 16(3), 606-613.

2) Hofer, H., & East, M. (1995). Population dynamics, population size, and the commuting system of Serengeti spotted hyenas. Serengeti II: dynamics, management, and conservation of an ecosystem, 2, 332.

3) Holekamp, K. E., & Smale, L. (1998). Behavioral development in the spotted hyena. Bioscience, 48(12), 997-1005.

1 comment:

Dan said...

One thing you ought to be looking at is whether the animals doing the killing are ranked below or above the mother of the cubs being killed, and whether the killers are male or female.

Logically, breeding males should not be killers of cubs at all because doing so doesn't benefit them or their offspring. Killing a cub is either killing possibly their own offspring, possibly a future mate, or another new male who's going to get ousted as he reaches adulthood. No pay-off in any direction there.

However, a female who ranks lower than the mother of the new cub would, by killing that cub, be reducing the number of animals that in future would out-rank her own offspring (which inherit her ranking). Killing the cubs of higher-ranking females would therefore be useful for her own offspring; social climbing by infanticide.

Is this the case?

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