Australasian Science: Australia's authority on science since 1938

A Reproductive Riddle

Scanning electron micrographs of the penis from a fawn hopping mouse (left) and spinifex hopping mouse (right) showing the narrower shaft but much larger spines that enable the spinifex hopping mouse’s penis to lock into place during mating.

Scanning electron micrographs of the penis from a fawn hopping mouse (left) and spinifex hopping mouse (right) showing the narrower shaft but much larger spines that enable the spinifex hopping mouse’s penis to lock into place during mating.

By Bill Breed

They look cute and even like to cuddle, but what do the small testes and spikey penis of the spinifex hopping mouse tell us about their ability to survive and thrive between periods of drought and flooding rain?

Bill Breed is a Professor at The University of Adelaide and co-author of Native Mice and Rats (CSIRO Publishing, 2007).

The full text of this article can be purchased from Informit.

Many people will be aware that marsupials and monotremes have been present on the Australian landmass since the breakup of the southern supercontinent, Gondwana, 50 million or more years ago. Less well known is the fact that the first native rodents arrived in Australia from South-East Asia around six million years ago and now make up approximately a quarter of all Australia’s land mammal species.

There are two major groups of native rodents: the New Endemics and the Old Endemics. The New Endemics are composed of eight or so species of rats in the genus Rattus whose ancestors arrived in Australia around one million years ago. The Old Endemics first arrived around six million years ago and comprise a more diverse variety of around ten genera that exhibit a range of body forms and sizes, from the delicate mouse weighing 8 grams to the carnivorous water rat and giant white-tailed rat that weigh up to nearly 1 kg.

Old Endemic rodents occur in a range of habitats throughout Australia and include a group of bipedal species that are specialised for life in sandy regions. The most widespread of these species is the spinifex hopping mouse (Notomys alexis), which weighs around 30 grams. It ranges from south-western Queensland, across central Australia to the coast of Western Australia in the Shark Bay region.

Individuals of this species are quite commonly kept...

The full text of this article can be purchased from Informit.