Komodo dragons live on a handful of islands in Indonesia, but their reputation has spread far and wide. Reaching lengths of up to 10 feet, the razor-toothed monitor lizards hunt deer in packs and have even attacked humans on occasion. But actually, they are real homebodies, according to a study published Wednesday in Proceedings of the Royal Society B.

A decade of observations at 10 sites on four islands has revealed that the dragons essentially never leave the valley where they were born. It’s not that they can’t. They are capable of traveling many miles and through rough terrain, if necessary. They just don’t seem to feel like it.

Many island species, as it happens, show a marked tendency to stay close to home. It feels like a bit of a paradox: Their forebears may have arrived on that island through some great feat of survival or exploration, but the present generation prefers familiar comforts.

“Once they colonize an island, despite these incredible feats of long-distance dispersal, they decide, ‘Enough is enough!’” said Tim Jessop, the professor of ecology at Deakins University in Australia who led the study.