Knee deep in trouble: rusa deer use an aquatic escape behaviour to delay attack by Komodo dragons

Abstract

We document six observations of an aquatic behaviour used by rusa deer (Rusa timorensis) to delay an imminent attack from Komodo dragons (Varanus komodoensis). This unusual behaviour arose after rusa deer fled into the nearby seawater following an attack from a solitary Komodo dragon. Once in the sea, rusa deer remained relatively stationary by standing in shallow water (<1 m deep) for up to 4 h. This behaviour generally allowed rusa deer to avoid an in-water attack from Komodo dragons. However, if rusa did not die from injuries, they moved back onto land and were subsequently killed by Komodo dragons. The aquatic behaviour delays subsequent attacks on rusa deer by Komodo dragons, but this appears only to postpone, rather than prevent, the deer’s death.