Animal Diaries Archive
25 July 2008
Birds have forelimbs that are modified so that the arm, forearm and hand support their wings. Wings are covered with flight feathers and covert feathers. The structure of a feather is an extremely successful and very efficient combination of lightness and strength. The feathers get the strength from barbs with interlocking barbules. So without wings the birds will be unable to fly. Flying is locomotion through the air.
Kangaroos don’t have wings or feathers yet they can very efficiently move through the air. You might be thinking why I am making this correlation. Well, I have worked at the Zoo for four years in the bird department and I am having a small holiday (change is good as a holiday). Even though my destination is kangaroos, I still think bird things.
A macropod’s powerful leg muscles and stretchy tendons store and release energy like an elastic band. They cannot move their hind legs independently of each other which means double the power. A Red Kangaroo can seemingly fly three metres above the ground and six metres across the ground. The tail is used as a counterbalance and steering which is the same as a birds tail feathers. The foot is uniquely designed for how they spring into the air. When looking at their foot there is three noticeable toes. The outer toe is for balance; the middle toe is extra long for thrust when hopping and the interior toe is three fused to one for grooming.
So you can see two totally different animals, to very different body parts, yet they both technically fly through the air.