Things turn nasty in The Squeak Fighter Victor Tyakht/Alamy Stock Photo

What do you want to watch tonight? If you’re more interested in an action movie than something more sexually explicit, you’re not alone.

A study that presented mice with multiple movies, played on iPods, has found that the animals spent longer watching other mice fighting than watching them copulating.

Shigeru Watanabe of Keio University in Japan and his team tested mice to see if they could distinguish between video clips of different social behaviours. They used three scenes – one of mice sniffing each other, another of two mice fighting, and the third of a copulating pair – and played them on a loop on iPods, without sound.


They placed an iPod in each of two side compartments of an enclosure, each playing a different video, and recorded the time spent in each compartment by 40 male mice with no sexual experience.

Sniff movies

The mice were least interested in the sniffing video. Given a choice between sniffing and copulation clips, 65 per cent of the mice spent more time watching copulation. The average mouse spent 41 per cent of the time in the copulation clips compartment, and 34 per cent in the other one.

But the fighting video was the favourite. Given a choice of that and watching copulation, the mice spent an average of 40 per cent of their time in the fighting compartment, and 35 per cent in the copulation compartment.

The results may reflect which videos the mice find most socially informative. The fight scene might have been the most interesting as it revealed information about dominance relationships, the team concludes.

Silent fight

In a second experiment, the team used reward-associated training to prove that the mice were able to tell the difference between videos of fighting, copulation and sniffing, even for clips they’d never seen before.

House mice mainly use their senses of hearing and smell to interpret the world, so the fact that they can distinguish between silent videos of fighting and copulation is interesting, says Barbara König at the University of Zurich in Switzerland.

But she is not convinced that the mice chose which videos to watch based on which were the most socially informative.

“There is a debate over whether time spent with a specific cue is a good proxy for preference. Mice might just need longer to gain information on whether the objects signal any kind of danger,” she says. König suggests it’s possible that similar videos, using objects that moved in a similar way to the mice, may have given the same results.

Journal reference: Animal Cognition, DOI: 10.1007/s10071-016-0953-x

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