Water Rat (Hydromys chrysogaster), John Gould (1863). Reproduction Photo by Marnie Rawlinson, Cathy Accurso and Ken Walker © Museum Victoria.

This beautiful animal is our native Water Rat. Though seldom seen, it occurs throughout Victoria and much of Australia, except for the arid interior. It is the largest of about 50 native rodent species surviving in Australia today (several species have become extinct during European history). Males can weigh up to 1.2 kg, though females are a little smaller.

I recently disturbed a Water Rat at the carcass of a fresh Wombat road-kill under Smiths Bridge, Strathbogie. After eying me off for a few seconds, it fled into long grass on the bank of the Seven Creeks . Upon closer inspection, I saw it had been feeding on the Wombat’s brain, having chewed a hole through the skull into the brain cavity. I presume the Water Rat made the hole, as the whole had been freshly opened up and the Water Rat was at the scene and I’m not sure anything else could neatly and easily get through the Wombat’s skull bones, other than this carnivore.

Without a doubt, brains are a nutritious feed and many carnivores are known to eat the brains of prey. Now, in addition to “fish, large aquatic insects and other arthropods, molluscs, crustaceans, and small or juvenile birds and eggs and fresh aquatic carrion” (Seebeck in Menkhorst 1995, Mammals of Victoria), we can add “Wombat brains” to the list of items Water Rats are known to eat.