The Red Kangaroo is a common marsupial from the plains and dry grasslands of Australia .
Females are faster than males and are called a doe , flyer , roo , or jill .
An adult male is called a buck , boomer or jack . A baby is called a joey . These shy animals live about 6 years in the wild and up to 20 in captivity. Kangaroos are considered pests due to the damage they do to crops. A group of roos is called a mob .