When the tadpoles first emerge, the head and tail are not much differentiated. There are small gills on the outside that are then absorbed. After about a week, the head is visibly different from the tail and begins to be more oval than round in shape. The tiny tadpoles cluster round the spawn for a week or more before launching out into the pond. There is safety in numbers and they cluster in the centre of the spawn so the remains of the spawn create a barrier (as well as the surface weed) between them and the predators.
When the tadpoles leave the safety of the spawn (which is now fairly ragged) they seem to gravitate to the shallows or the edges of a pond. They hang motionless on bits of weed. If they are not attached to weed or are not wiggling, they sink to the bottom. Predators include dragonfly larvae. A larva will surface like a crocodile and grab the wriggling tadpole. Their attack is probably triggered by a tadpole’s movement since they seem to ignore the motionless ones. Losses are high.