The tadpoles of the red-eyed tree frog can choose to hatch early to avoid being eaten by snakes, says Karen Warkentin from the University of Texas in Austin (New Scientist. Vol 146, No 1974).

The eggs hatch in a matter of minutes and can do so when they are 5-7 days old. Warkentin claims that early hatching is more than just a general response to mechanical disturtbances. A mere touching the eggs had no effect but if a pair of forceps is moved into the jetty in which frog eggs are embedded - the movement simulates a snake attack - the eggs hatch quickly.