Mammals
Swamp Wallaby
Wallabia bicolor · also called black wallaby, stinker
Browsing on ferns that would sicken many other grazing animals, a swamp wallaby forages through dense forest undergrowth, quietly carrying both a nursing joey and a developing embryo at once, a reproductive trick found in no other member of the kangaroo family.
Overview
The swamp wallaby, Wallabia bicolor, is the sole surviving member of its genus, native to forest and wetland habitat across a broad range spanning eastern Australia. Its unique overlapping pregnancy strategy, distinct chromosome number setting it apart from true kangaroos and wallabies, and tolerance for plants toxic to many other grazing animals make it one of the more biologically distinctive members of the kangaroo family found anywhere in Australia.
A wallaby that plays by different rules
Genetically and reproductively distinct enough to stand alone in its own genus, the swamp wallaby manages a feat no other kangaroo family member can match, carrying a developing embryo in reserve even while its previous joey is still nursing.
Status
Least Concern, remaining widespread and common across suitable forest and wetland habitat throughout eastern Australia.
Swamp Wallaby: common questions
Why is the swamp wallaby considered unique among kangaroos and wallabies?
This species is the only living member of its genus, distinct enough from true kangaroos and wallabies to be classified separately, including having a different chromosome number, one of several genetic and biological differences that set it apart from its close relatives.
What does it mean that the swamp wallaby has overlapping pregnancies?
This species can become pregnant again shortly before giving birth to its current joey, resulting in a female effectively carrying a developing embryo and an older joey at different life stages virtually simultaneously, an unusual reproductive strategy among mammals.
Why can the swamp wallaby eat plants other animals avoid?
This species can safely eat a range of plants, including some ferns and shrubs, that are toxic or unpalatable to many other native and introduced grazing animals, giving it access to food resources that many competing herbivores cannot use.
Why is the swamp wallaby sometimes called the stinker?
This species is sometimes given this nickname due to a distinctive, musky body odour that some observers find notably strong compared with other wallaby species, though the smell does not appear to cause the animal any particular disadvantage.