Secrets of the tuco-tuco society

By Aussiegirl

An interesting article on a rare rodent that should be extinct by now, but isn't, giving scientists the idea that species may owe their survival to weathering population crashes by becoming more social.

Telegraph | Connected | Secrets of the tuco-tuco society

Secrets of the tuco-tuco society

A rare rodent that should, by rights, be extinct has given scientists an insight into the role of social behaviour in the survival of species, writes Roger Highfield.

A toothy rodent that lives in burrows in the remote highlands of Patagonia might appear to be a glorified gopher of little interest to anyone except Sir David Attenborough.

Today, however, scientists from Stanford University announce that a DNA analysis of the "colonial tuco-tuco" (Ctenomys sociabilis ) could solve the mystery of why the rare rodent survives and, in turn, suggest how the rise of human society was driven by times of extreme hardship.

The subterranean rodent fascinates biologists because it has so little genetic diversity that the slightest whiff of climate change, competition or disease should have made it extinct long ago.

Yet the hearty gopher-like creature has not only managed to survive for thousands of years in a harsh climate, it has also evolved a complex social structure that is unique among the more than 50 closely related tuco-tuco species. [....]

"Adopting a colonial lifestyle may have been the key to the rodent's survival," said Dr Elizabeth Hadly, whose team reports, in the journal Public Library of Science Genetics, on how DNA from tuco-tuco teeth suggests that its thriving social life was given a lift by almost being wiped off the face of the Earth. [....]

No one knows exactly when C. sociabilis began to live up to its name, but Dr Hadly suspects it was a response to the population crash. "Maybe the evolution of sociality actually confers some advantage to withstanding periods of low genetic diversity," she says. "Most behaviourists would say that sociality is so complicated that it takes a while to evolve, but maybe if a species has to be social to survive, social behaviour could evolve pretty rapidly."

If so, the study of rare Patagonian tuco-tucos could have implications for understanding the evolution of social behaviour in other species that have suffered evolutionary bottlenecks, which includes man: perhaps the first glimmers of human society appeared in the wake of an ancient population crash.