This is Scientific American's 60-Second Science, I'm Jason Goldman.

Morning in Tanzania.

The sun rises over the Gorongoro crater.

The spotted hyenas are beginning their day, while Eve Davidian from Germany's Leibniz

Institute for Zoo and Wildlife Research sits nearby in a truck, watching and waiting.

The most exciting part of her day is when a male hyena crouches on his hind legs to poop.

So I did collect a lot of fecal samples, monitor a lot of behaviours, spend a lot of time

following males on site in Tanzania in the field.

Biologists have been monitoring the eight hyena clans of Tanzania's Gorongoro crater

for 25 years.

They've learned a lot about the species, but there are still some outstanding mysteries.

Why is it that high-ranking individuals and in particular high-ranking males often

are more successful than low-ranking males in terms of reproduction in spotted hyenas

in contrast to many of the mammals, males don't fight to access a high social rank and

they also don't fight to access breeding partners.

And so it is quite puzzling why high-ranking males, if they don't fight and they are not

necessarily more attractive to females, why they should be more successful than males

of low social rank.

In all, Davidian had nearly 400 fecal samples collected from 120 male hyenas.

She analyzed the hormones inside of them and discovered that interactions among male hyenas

were more stressful for low-ranking males.

And as a result, they spent more time alone.

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