The brown tree snake is very distinctive because of its large head with bulging eyes and its long slender body. Lengths in excess of 2 metres have been recorded, though 1.5-1.8 metres is a more common size. The colouration is usually a medium brown background with a series of darker markings or bands. Some northern specimens are strikingly banded with rich reddish-brown and creamy-white and are sometimes called ‘night tigers’. Brown tree snakes are notorious for their bad temper and will strike repeatedly if they feel threatened. They are venomous but the fangs are at the back of the mouth so only a very large snake would be able to inject venom into a human. For this reason they are not regarded as being dangerous.
The brown tree snake is found in woodlands, rainforests and open rocky outcrops. It often takes shelter in hollow trees, caves and in rock crevices. It occurs over much of coastal eastern and northern Australia from the Sydney area to the Kimberleys in Western Australia.
The diet comprises mostly birds and small mammals but this may be supplemented with small lizards, particularly by juvenile snakes.
The female brown tree snake lays between 4 and 12 eggs in each clutch. These are usually laid in a rock crevice or tree hollow.