This is scientific Americans 60 Second Science. I'm Jason Goldman. Got a minute?

Humans aren't the only species that forms friendships. Lots of animals prefer to spend their time with only certain individuals.

It's all very well showing that you do get social relationships, and social bonds forming, but why on earth would you form them in the first place.

University of Exeter Animal Behavior researcher Rob Heathcote.

He and his team wanted to find out what benefit animals derive from close social relationships.

To do it, they set out for the Caribbean island of Trinidad, home of a small freshwater fish

called the Trinidadian Guppy.

These Guppies live in environments that have tons of predators around.

So basically it really sucks to be in a guppy in some of the places they live.

You know you'll be watching these shores of Guppies and a predator is

attacking them probably every,

you know, 20, 30 seconds or so.

One common idea is that such animals form social groups to reduce the risk of being gobbled up.

But Heathcote wanted to see whether the benefits of social living might come from the strength of individual social relationships rather than simple safety in numbers.

The researchers caught 240 feet. rather than simple safety in numbers.

The researchers caught 240 female Trinidadadion guppies and divided them into groups of 15,

each group in its own small pool.

While some of the fish were left alone, others were exposed to what

looked like a predator, a dull version of a guppy-eating fish called a pike sicklet.

Those guppies exposed to the erste's predator were more likely to establish stronger social

bonds, but the groups formed by those guppies were on average smaller than the groups formed

by the fish that were not exposed to predators.

...