Pygmy Possums: Burramyidae

Pygmy possums, like most animals native to Australia and New Guinea, are marsupial mammals. This type of mammal, unlike familiar eutherian (yoo-THEER-ee-an) mammals such as dogs, cats, or humans, does not have a well-developed placenta. A placenta is an organ that grows in the mother's uterus (womb) during pregnancy in order to share food and oxygen with the developing young. Since marsupial mammals like pygmy possums do not have a well-developed placenta, their young are born hairless, blind, and underdeveloped and must complete development inside their mother's pouch.

Pygmy possums look much like common mice. They are small, between 2 and 4 inches (5 to 10 centimeters) long, and they weigh between 0.2 and 1.4 ounces (7 to 40 grams). They are covered with soft fur that is brown on their backs and lighter underneath.