Kangaroos are typical representatives of marsupials. Marsupials are immature animals and belong to premature fetuses, so they need to develop in nursing bags. The female kangaroo has four nipples, two with high fat and two with low fat. Generally speaking, female kangaroos give birth to 3 to 4 baby kangaroos per litter. Kangaroos should be bagged after birth and eat low-fat milk.

This determines that each kangaroo can only survive two; Kangaroos are very small at birth, only about 1 peanut. Adult kangaroos are 1.3 ~ 1.5 meters tall and weigh up to 50 kilograms.

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Kangaroos can jump and run very fast with their lower limbs, and the speed can reach more than 50 kilometers per hour. Kangaroos have a "multifunctional" tail, which plays a very important role. When resting, you can support yourself on the ground and balance your body with your lower limbs. Tail is an important balance tool in running, and kangaroo tail is also an important weapon for attack and defense.

All kangaroos, no matter how big, have one thing in common: strong hind legs and long feet; The central index of kangaroos (namely, the index of (calf length/thigh length) × 100, or the index of (tibia length/femur length) × 100) reaches 172, of which red kangaroo reaches 202, far exceeding other animals, while human beings only have an average of more than 80.