Wheel-running in the wild

21 05 2014

Strange paper in Proc Roy Soc today. It’s very interesting but really doesn’t mean what they say it means. Hanno and I were both interviewed about it for USA today

Hmm, here is what I actually said to the journalist:

This fascinating study shows that normal wild animals can be ‘tricked’ into the pointless activity of running on the spot. Presumably it feels as good to them as do truly useful activities like searching for food or a new territory (a bit like the way we find candy highly rewarding — even though it’s bad for us — because we’ve evolved to like valuable natural high energy foods like fruit and honey).

Modern definitions of stereotypic behaviour (activities common in captive animals, like pacing and rocking in zoo-housed carnivores and primates) rely on its causes, not on what it looks like. True stereotypic behaviours are caused by developmentally abnormal brains and the frustration of natural behaviour. The wheel running performed by these wild animals is therefore definitely not a stereotypic behaviour.

However, what does this new finding say about wheel-running by caged lab rodents? Not that much I’m afraid. It could still be that wheel-running in caged animals has an obsessive or compulsive quality that’s missing in wild animals. One of the incredible things about wheel-running by caged rodents is that some of them spend hours a day doing it, and covers tens of kilometers in 24h. This is quite extreme! Are any of the wild animals doing anything like this? Who knows — the authors can’t say, because they could not tell individual animals apart.

The authors’ conclusion is therefore a bit like saying “normal children suck their thumbs; therefore it’s always a normal behaviour, even if adults do it”. Just because normal animals do it, does not mean that all forms of this behaviour – no matter how extreme – are therefore normal.