These "hitchhiking intruders" have included a tree frog that emerged from roses at a florist's shop in Sheffield and snakes discovered in ornamental olive trees shipped across mainland Europe.

This technique, called startle coloration, may give a bird or snake pause ... Many of the animals that eat red-eyed tree frogs are nocturnal hunters that use keen eyesight to find prey.

These "hitchhiking intruders" have included a tree frog that emerged from roses at a florist's shop in Sheffield and snakes discovered in ornamental olive trees shipped across mainland Europe.