Many amphibians produce noxious secretions from their skin to deter predators, and rain frogs Breviceps spp., found in Southern Africa, are no exception.
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When threatened, they exude a milky-white fluid that has earned them the name melk-padda or 'milk frog' in Afrikaans.
But a rain frog's secretions have a second, more important function: to glue it to a mate.
Unlike most frogs, who lay eggs in water, rain frogs lay them underground. And if the male isn't firmly attached to his partner during the burrowing process, he is likely to be dislodged before the eggs are laid and fertilised.
Yet the glue doesn't always allow for the perfect pairing. It is not unknown for males to get stuck in the wrong position - back to front, or sideways on - or for groups of individuals to become hopelessly welded together in the scrum for mates.
And this effective adhesive ensures that there's no chance of a quickie divorce when such mismatches occur.
Rain frogs have no free-swimming tadpole stage. Instead, larvae are provisioned with large yolk sacs that nourish them after hatching. They emerge from the burrows as complete little frogs
Rain frogs get their common name from their habit of emerging from their burrows in great numbers after rain.
When threatened, they can puff themselves up with swallowed air to intimidate predators, and squeal disturbingly.
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