Last year we learned that climate change could soon make Australia too hot for the cold-loving, iconic platypus ( Ornithorhynchus anatinus ). Now we have word of a new threat to these unique, egg-laying mammals: inbreeding, which has put the platypuses living on two small Australian islands at enhanced risk of disease.

According to research published March 28 in Ecology and Evolution and May 4 in the Journal of Heredity , the platypus populations on mainland Australia and its island state Tasmania have perfectly normal levels of genetic diversity. But populations on two nearby islands aren’t in as good shape. University of Sydney doctoral student Mette Lillie, lead author of the Journal of Heredity paper, says platypuses on the 1,100-square-kilometer King Island located off the coast of Tasmania and separated genetically from the mainland by the last ice age 14,000 years ago now show no diversity in their major histocompatibility complex ( MHC ) gene, putting them at high risk of an epidemic disease. “If you have lots of variation in the MHC gene, it means the population is better able to resist disease and pathogens,” she told the Australian Broadcasting Corp (ABC). Lillie was one of the researchers who sequenced the platypus genome in 2010.