Baby kangaroos (joeys) are the size of a jellybean when they are born. When first born, they are less than 2cm in length and weigh around half a gram. A baby kangaroo (joey) when born is blind, hairless and completely helpless, clawing its way by instinct from the birth canal of the mother kangaroo up to and into the pouch. The joey then latches onto a teat inside the pouch, which then swells inside mouth of the joey, basically securing it from falling or being jolted from the pouch. The joey then continues to form and grow, and according to the different species, reaches different sizes by adulthood.