Despite its name, this spine-covered animal has a relatively elongate, slender snout. The spines are usually yellow with black tips but can be entirely yellow, and provide excellent defence against predators. Insulation is provided by a covering of fur between the spines, which ranges in colour from honey to a dark reddish-brown and even black. A number of subspecies of the short-beaked echidna have been described, distinguished by characters of their fur and spines. For example, the fur is thicker and longer in the most southerly subspecies (Tachyglossus aculeatus setosus), which inhabits Tasmania, than those inhabiting warmer areas. This echidna is adapted for very rapid digging, having short limbs and powerful claws, with the hind claws elongated and curved backwards. All short-beaked echidnas possess spurs on their hind feet; however, unlike the platypus (another monotreme), these spurs lack venom.