Komodo dragons are an astonishing sight, their intimidating size only augmented by their venomous bites and keen hunting abilities. Capable of long-distance travel and dominating most other animals, some have wondered why they aren’t more widespread.

It turns out that these human-sized lizards are perfectly content to stay close to home, rarely—if ever—venturing outside of the valleys they hatched in, according to new research.

A study published this week in Proceedings B of the Royal Society is the product of a decade of observations of the reptiles’ movement patterns in the only place on Earth these animals reside: a handful of craggy islands in Indonesia’s Lesser Sunda archipelago.

The paper found these animals are highly mobile and athletic, sometimes moving up to