Ground beetles often live under the bark of trees, under logs, or among rocks or sand by the edge of ponds and rivers. Most species are carnivorous and actively hunt for any invertebrate prey they can overpower. Some run fast to catch their prey; tiger beetles (Cicindelinae) are certainly fast runners in comparison to their length. Unlike most Carabidae, which are nocturnal, the tiger beetles are active daytime hunters and often brightly coloured. They have large eyes and hunt by sight. Ground beetles of the species "Promecognathus laevissimus" are specialised predators of the cyanide millipede "Harpaphe haydeniana". They can counter the hydrogen cyanide which makes these millipedes poisonous to most carnivores.