Toad partners

Source:, photo Patrick Gijsbers
When several males fight over a female Cane toad, the female selects the biggest and fittest male. She can throw a less wanted male off her back by blowing herself up.
During the mating season the females of many amphibian species are lured by quacking males. When a female passes the male jumps on her back and waits until she lays her eggs, which he can then fertilize. This mating positing is called amplexus and can last up to several days. This can lead to much competition among the toads.
But a female Cane toad (Bufo marinus) has thought up a way to get a less desirable male off her back. She blows herself up so that the sitting male cannot hang on to her very well. A bigger and fitter male toad can now conquer this position. If the female then reduces her size the winner is locked tightly onto her back in amplexus and can now longer be chased off by other males.
Animal ecologist Bas Bruning from the Vrije Universiteit Amsterdam discovered this by performing tests with toad pairs.
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