Australia's Lost Giant
During the Pleistocene epoch, the forests of what is now Southwestern Australia contained a bizarre and giant mammal. Murrayglossus hacketti, also known as Hackett's giant echidna, was the largest monotreme (egg-laying mammal) ever to exist. It reached about one meter (3.3 feet) in length and weighed an estimated 30 kilograms (66 pounds), roughly the size of a modern sheep. This makes it significantly larger than its living relative, the short-beaked echidna, which weighs between 2 and 7 kilograms. Like modern echidnas, it would have been covered in spines for defense.
The animal belongs to an ancient line of mammals, the monotremes, which diverged from other mammals around 220 million years ago. This group, which today includes only the platypus and four species of echidna, retains primitive characteristics like laying eggs but also possesses mammal traits like producing milk and having fur. M. hacketti had proportionally longer and straighter legs than modern echidnas, which may have made it better suited for moving through the wooded environments of its time. Its diet likely consisted of invertebrates like worms and insect larvae, which it would have consumed with a long, sticky tongue. The genus name Zaglossus, to which it was formerly assigned, means "great tongue."