sustainability through science & innovation

Native water rat capture assists Healesville Sanctuary

26 May 2012

The Wildlife Ecology team from cesar recently assisted Healesville Sanctuary in the capture of a wild Rakali (Hydromys chrysogaster) to add to their captive colony. Additional individuals were required to maintain genetic diversity within the captive population of Rakali (native water rat), which are on display at the Sanctuary. An adult male Rakali (nicknamed ‘Boris’) was captured in western Melbourne and relocated to Healesville Sanctuary in late March.

 Also known as ‘water rats’, Rakali are semi-aquatic native rodents found throughout Australia and overseas in New Guinea and Indonesia. Despite having an extensive range throughout Australia, there is relatively limited knowledge of their ecology, behaviour and population status. Signs of Rakali (holes chewed in nets) are frequently observed throughout Melbourne during platypus surveys conducted by cesar but appear to be more abundant in the western suburbs. Unfortunately, like many other native rodent species, Rakali have a poor reputation due to comparisons with their introduced pest relatives.

 Rakali are top order predators in aquatic environments with a diet ranging from insects through to fish and even small water birds. They are striking creatures and can grow up to half a meter in length (including tail) and weigh about 1 kg. Their specialist features include webbed hind feet and dense coat of waterproof fur. Sometimes mistaken for a platypus while swimming, Rakali are easily distinguishable by their long slender black tail with a distinctive white tip. Rakali are best seen at dawn and dusk around undisturbed waterways, however often all you will see is a splash!

 After clearing quarantine, Boris now resides at Healesville Sanctuary and has settled into his new enclosure. It is hoped that Boris will contribute to the captive breeding program and assist in raising the public profile of Rakali and other native rodents.