Poison frogs have an internal homing device

Andrius Pašukonis

Poison frogs have an internal homing device

Drop a poison frog anywhere in its home range, and it can find the shortest way back to where it lives, according to a new study. This type of navigational ability is not common in amphibians, which are usually relatively sedentary. Poison frogs from the Amazon rainforest live among leaf litter on the forest floor, where they lay their eggs. Because tadpoles need water for development, parent frogs carry tadpoles on their backs to water-filled nurseries. The brilliant-thighed poison frog (Allobates femoralis, pictured) uses small puddles and pools on the ground. Males defend small territories about 15 m in diameter but have home ranges as large as 600 m in diameter. The researchers fitted the amphibians with tracking devices and dropped them more than 100 m from their homes. Frogs taken to a foreign territory appeared disoriented, but frogs dropped within their own home range made their way straight home using the most direct route, the team reports online today in Biology Letters. The animals spent no time learning landmarks along the way; they oriented themselves right at the start and took the shortest route. Water nurseries for tadpoles are temporary and widely spaced, which means parent frogs need an excellent map of their territories in order to drop off their offspring in the best ones, increasing their reproductive success. The journey away from home is also fraught with dangers, so a mental map is a huge advantage.