Pseudonaja nuchalis, commonly known as the western brown snake or gwardar, is a species of very fast, highly venomous elapid snake native to Australia. Its colour and pattern are rather variable, depending largely on its location. Some experts assert that the western brown's wide variation in appearance and extensive distribution mean that the western brown species in fact covers multiple related, but separate species with three derivative species now officially recognised, P. nuchalis, P. aspidorhyncha, and P. mengdeni.