Domesticated foxes show evolution of social intelligence.
For almost half a century, a population of foxes in Siberia has been bred to be unafraid of humans and non-aggressive. Now these foxes seem to have shown that social skills come as a perk of being friendly.
Dogs, domesticated from their wild wolf cousins over millennia, are not only less likely to bite or bolt, but have also gained the ability to communicate with their human companions. For example, if a human points or looks at an object, the dog will also look at it.
“We were really surprised - we all thought that the foxes were going to fail. Brian Hare , Harvard University”
Brian Hare, an anthropologist at Harvard University in Cambridge, Massachusetts, had previously shown that dogs are more likely than undomesticated animals - even chimps - to be able to communicate in this way with humans. But was this social sophistication something that was specifically bred for during their domestication, or was it a by-product?
An opportunity to find out came from the Siberian foxes, which have been bred for friendliness but have had limited contact with humans. The project was set up in 1959 by Dmitry K. Belyaev of the Institute of Cytology and Genetics in Novosibirsk to examine the genetics of domestication. Each fox is tested at the age of seven months to see whether they approach humans (and whether they bite). The 'friendlier' foxes are bred, and a separate, control, population is bred randomly.
Hare and his team studied fox kits that had spent "probably a grand total of 20 minutes" with humans, according to Hare, so they could not have learned how to interact with them. Introduced into a room with two hiding places for food and a human pointing and gazing intently at the one spot that actually concealed food, the 'tame' foxes took the hint and found it, whereas the 'wild' ones were flummoxed. The researchers report their results in Current Biology1.
"We were really surprised - we all thought that the foxes were going to fail," admits Hare. It seems, therefore, that social intelligence does not have to be specifically selected for. It simply comes along with friendliness.
Hare believes that his results have implications for the oft-debated origins of human social intelligence. Perhaps humans found it favourable to be less aggressive and fearful, and to be more tolerant and cooperative, and these changes brought along with them a boost in cognitive skills.
"Selection for being smart might not have been the first step," suggests Hare. "First you need to have a change in how you view your social world, so we had a platform from which these new abilities can evolve."
Other researchers caution that the results of the test can not be taken too far. Bruce Blumberg, who studies animal cognition at the Massachusetts Institute of Technology in Cambridge, and Ray Coppinger, a canine biologist at Hampshire College in Amherst, Massachusetts, say that one cannot quite say that this test definitively shows an ability in foxes. Perhaps the 'tame' foxes were just more interested in food, they suggest.
"Hare and colleagues' latest results are intriguing," says Blumberg. "But much much more work needs to be done before we can make any definitive claims, or generalize beyond the results that they have generated."
The specially domesticated foxes are not only socially adept, adds Hare, they are regular charmers. "They behave like dogs," he says. "They whine and bark, they wag their tails, they pee for joy, and they just want to cuddle with you."
But don't expect fox kits to be appearing in pet stores any time soon. The foxes have a pungent musk and love to dig and hide food, says Hare. "They would bury your food in your sofa and you would only find it three months later."
HareB., et al. Curr. Biol. 15, 226 - 230 (2005).