Short-Beaked Echidna (Tachyglossus aculeatus) in the high country of Tasmania, Australia. The Echidna, is one of the four surviving living mammals that lay eggs, and part of the order Monotremata. The spines, which reach 50 mm in length, are in fact modified hairs. Insulation is provided by fur between the spines which ranges in colour from honey to a dark reddish-brown and even black. The fur of the Tasmanian subspecies (T. a. setosus) has evolved to deal with the snow and is thicker and longer than that of echidnas in warmer mainland areas and therefore often conceals the spines. The diet of echidnas is largely made up of ants and termites, although, they will eat other invertebrates especially grubs, larvae and worms.