The Kangaroo's Extra Leg (Pentapedaling) Where is the Kangaroo's Extra Leg
Despite the kangaroo's reputation for gracefully hopping through the landscape, it actually spends more time moving at more leisurely pace of about 6 kilometres an hour as it feeds and socialises with other kangaroos. At this speed the kangaroo's movements are ungainly indeed. While highly efficient at higher speeds, a kangaroo's hind legs are cumbersome and almost useless at lower speeds. The kangaroo has adapted to this shortcoming by developing a fifth leg! Where is it, your wonder? It's the kangaroo's tail.
A kangaroo moves at low speeds by leaning forward on to its short front limbs, hoisting itself up with its tail and then shifting its hind legs forward. This method of movement is called 'pentapedal' (four limbs + tail) locomotion. Only the kangaroo does this. Recent research has shown that the kangaroo's tail with its 20 vertebrae acts like a fifth limb fulfilling the role of a normal leg. In this role it is capable of generating more forward force than all of the kangaroo's other limbs combined.