Kangaroo's life 
Kangaroos are mammals that belong to the marsupial family and have numerous distinguishing traits. They are entirely herbivorous, and one of their distinguishing characteristics is the pouch in which they raise their young. The kangaroo life cycle begins with sexual reproduction, but the embryo and developing joey dwell in the mother's pouch following a brief gestation period. While all mammals nurse their young, the kangaroo life cycle differs significantly from those of common North American herbivorous animals such as rabbits or deer.
Reproduction and Embryo Development in Kangaroos
Kangaroos, like other animals, reproduce sexually and mate when the female kangaroo is fertile. 
           The fertilised egg develops into a kangaroo embryo, but unlike other mammal embryos, it does not embed itself in a placenta for long-term sustenance. Instead, the embryo feeds on the contents of the yolk sac of the egg, which it consumes in about a month.

The kangaroo embryo is still in its early stages of development and is scarcely movement at this point. It's roughly an inch long, blind, and hairless, with stumpy back legs. 
           When it is born, it utilises its front legs to climb through the mother's birth canal.After around six months in the mother's pouch, the kangaroo embryo has grown quickly and developed into a newborn kangaroo, or joey. The joey has grown large enough to peer out of the pouch and can begin to graze on its own. By the end of this stage, the joey has gained independence and is spending larger lengths of time outside the pouch. It will still return to the pouch to sleep and nurse, and when it detects danger, especially in the beginning.
After another one and a half to two months, the joey is a mature kangaroo and exits the pouch on its own. As soon as the kangaroo embryo is implanted, the mother becomes fertile.
Lifespan and Behavior of Kangaroos

Kangaroos can live up to 20 years in captivity, but they often only live six years in the wild. Due to a high mortality rate for embryos and young kangaroos, the majority of kangaroos never reach maturity. Predators that pose a threat to young kangaroos in particular include:foxes, eagles, snakes, and wild dogs
 

Kangaroos live in herds known as mobs for defence and mutual protection. A herd of kangaroos will naturally flee from predators, but when cornered, individuals may fight by kicking and biting. The most common native mammal in Australia is the kangaroo, despite having a distinct and distinctive life cycle.