What physiological structure helps kangaroos to survive in desert regions?

Answer 1

Kangaroos do not live in desert regions where there is no food. They must live where there is sufficient fresh vegetation, and a permanent supply of water, as they cannot go for long without water (despite some website erroneously reporting that this is the case).

Kangaroos are uniquely adapted to survive living in the semi-arid and dry regions of Australia.

The mother kangaroo spends most of her adult life pregnant, but in drought times, she has the ability to indefinitely "freeze" the development of the young embryo until food sources are replenished. The mother can also produce two different types of milk to suit the needs of two different aged joeys. She might have a more mature joey that spends less time in the pouch, while a very young embryo has attached itself to a teat. Each joey has different milk requirements - which the mother is able to supply.

Kangaroos are able to travel long distances at a high speed, expending very little energy. They are very energy-efficient, and this is linked directly to the physical action of bringing their hind legs up with each hop. Every hop literally refills the lungs. They have large, strong tendons in their hind legs which act as "springs". The springing motion requires less energy than running does, so kangaroos are able to bound for longer distances than other mammals with the standard four legs can run. They have strong back legs and elongated hind feet for bounding.

Kangaroos are more active in the cooler hours of the early morning and the late afternoon. During the heat of the day they are more sedentary, lying around quietly and chewing their cud. In hot weather, kangaroos use saliva to cool down, licking their forearms where there is little muscle tissue and blood veins run close to the surface. When the saliva evaporates from the fur, it cools down the kangaroo.

The teeth of the kangaroo are continuously being worn down by the tough grasses they eat. Instead of continuously growing, once a kangaroo's front teeth are worn down completely, they fall out, and the back teeth move forwards to take the place of the worn front teeth. Kangaroos have four such pairs of chewing teeth.