These pouched rats are the only family of the pouched order Didelphimorphia. They live only in America and are the biggest pouched animal family that live outside of Australia. The name "Opossum" is very widely used as well as pouched rat.
Pouched rats resemble to rats or mice in terms of looks. They can reach the length of 8-50 cm and weight of 13 gr- 5 kg. Their fur is short, dense, wool-like and mixed colored. Their tails are mostly longer than themselves. Many species use their prehensile tail to climb and grasp. Their legs are short and their feet have a big toe.
Pouched rats are mostly nocturnal and live alone. Most of the species live on the trees and others on the ground. The water opossum has a suitable body structure for living in water.
In the family of pouched rats there are few species that actually have a pouch. The ones who don't have a pouch have a skin layer under which between 7 and 27 teats, where the pouch would be located. Their gestation, which takes around 12-14 days, is very short and actually the shortest among mammals. They always give birth to many babies whose development also takes a short time. The life expectancy of the most species is around 1-2 years.
These cute creatures, who we also come across with in the animation series Ice Age, are known best for their reaction to danger: playing dead (or playing opossum). Opossum is smart... When we see such animals, we usually can't help but think "Where the hell do other people find and keep such animals?"Source: http://onedio.com/haber/opossum-zoru-gor...