Proc. R. Soc. Lond. B doi: 10.1098/rspb.2008.0794 (2008)

In Bibron's toadlet (Pseudophryne bibronii) males are the nestmakers and females shop around. Females of this Australian amphibian lay their eggs in the nests of up to eight males. This makes it the first frog or toad in which such 'sequential polyandry' has been genetically proven, and the most extreme example of this mating tactic seen in any vertebrate.

Using DNA analysis and observations, Phillip Byrne, of Monash University in Melbourne, and his colleague showed that females that laid eggs in more nests had more surviving tadpoles. They suggest that polyandry is an insurance policy against nests flooding or drying out, and that other egg-layers in which dad tends the brood in a risky environment may do the same.