This is not scientific Americans 60 Second Science. I'm Jason Goldman.

Turns out that for hyenas, it's not what you know, but who you know. Spotted hyenas live in large mixed sex

clans with fairly stable social hierarchies and the females are in charge. The matrilineal hierarchies that we see in spotted hyenas are also found in a lot of old world monkeys.

Michigan State University biologist Eli Strauss.

It's been perplexing for a long time to a number of people what forces maintain this system

because it's somewhat unusual in the animal kingdom.

In some kinds of animal societies, your place in a dominance hierarchy can be explained by physical attributes like body size.

But in other animals, dominance rank can be acquired through things like age or nepotism.

Strauss and colleagues collected data about five generations of four groups of wild spotted hyenas in Kenya that they observed

over a 27 year period.

And the researchers saw multiple instances in which a smaller hyena came to dominate a larger one.

They've even seen severely wounded hyenas become dominant to healthy ones.

The results are in the journal Proceedings of a National Academy of Sciences.

Given those examples, it would seem that Rank and spotted hyenas is fairly arbitrary.

But it turns out that what researchers call hyenas is fairly arbitrary.

But it turns out that what researchers call ring reversals happen only rarely in this species,

just 14% of the time.

So how does it stay so stable over time?

They are systematically related to the coalitionary support

that we observed.

So females who had stronger coalitions with their top allies were more likely to increase their social rank.

Spotted hyenas could only climb the social ladder if they were able to maintain a strong alliance.

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