Sydney, Sep 2 - Reptiles are never the most social of creatures but when it comes to laying eggs they don't mind sharing nests.

A new study from the Australian National University (ANU) suggests that this out-of-character behaviour is more common in reptiles than was previously thought.

Scientists from ANU's Research School of Biology performed an exhaustive review of literature on reptile egg-laying.

Sean Doody and colleagues Scott Keogh and Steve Freedberg found that communal nesting has been reported in 255 lizard species as well as many species of snakes and alligators. The behaviour was also documented in 136 amphibian species.

'Most of what we know about communal nesting in animals with backbones comes from birds, which typically have conspicuous nests,' Doody said.

'In contrast, nests of reptiles and amphibians are generally difficult to find. It was previously thought that about five percent of reptiles and amphibians lay eggs communally.

However, if we exclude species for which nests are not known that the proportion rises dramatically to 85 percent or more, at least for Australian lizards.