Zaglossus hacketti is an extinct species of long-beaked echidna from Western Australia that is dated to the Pleistocene. It is known only from a few bones. It was about 1 m long and probably weighed about 30 kg (66 lb). This makes it the largest monotreme known to have ever lived. Due to the lack of cranial material, placement of Z. hacketti into the modern long-beaked echidna genus Zaglossus is uncertain.