331. A Lizard that Builds with the Family in Mind

The great desert skink creates and maintains tunneled compounds

By Nicholas Bakalar, The New York Times, May 17, 2011

Many animals build houses for their offspring, but no one thought lizards were among them. Now researchers have found that great desert skinks, lizards that live only in northern Australia, build and maintain elaborate tunneled homes, where they live in cooperative multigenerational family groups.

The lizards, whose scientific name is Liopholis kintorei, build structures that are more or less permanent addresses, with about 6 percent of the tunnels becoming disused each year. Females tend to stay at home — only one was found in a burrow system different from her offspring’s, and genetic analysis showed that about 60 percent of males are faithful spouses. Parents were captured in or near burrows where their offspring lived. The children hang around home, too — most burrow systems contain only full siblings of different ages.

The large amount of energy expended to build and maintain the structures suggests that the behavior has great survival value, and the researchers, writing in PLoS One, suggest that such conscientious parental care provides an evolutionary fitness advantage. So far as is known, the elaborate home construction is unique among lizards, a group that contains at least 5,000 species.

Adam Stow, an author of the study and a senior lecturer in biology at Macquarie University in North Ryde, Australia, said that very few other lizard species form family groups, and that those few live in rock crevices that require no maintenance.

The habits of the great desert skink were certainly known to residents of the arid Central Australia region of the Northern Territory, but they had not been described scientifically. “It’s such a remote part of Australia,” Dr. Stow said, “that few people go out there.”