Skulls of Giant Rat and Black Rat (IMAGE) CSIRO Australia Caption The skull of a black rat (right) compared with a fairly complete skull of one of Timor's other extinct giant rats (left). The giant rat shown here isn't the biggest of the extinct rats, which was around 25 per cent bigger again. The black rat (Rattus rattus) is one of the world's most common rat species. It is also known as the house, roof or ship rat and is found throughout Africa, Asia, Australia, Europe and the Americas. A typical adult weighs about 150 grams. The skull of the black rat shown here is 35 mm long. Credit Ken Aplin, CSIRO Usage Restrictions Credit: Ken Aplin, CSIRO License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.