A newborn kangaroo, called a joey, is extremely small at birth-about 1 inch (2.5 centimeters) long, roughly the size of a grape or a jellybean

. They weigh less than two grams (less than an ounce), making them the smallest marsupials at birth

. Despite being born so tiny and underdeveloped, the joey crawls unassisted through its mother's fur to the safety of her pouch, where it continues to grow and develop