Your morning adorable: American bison calf at Vienna zoo
Female bison, like mother Resi here, are called cows. (Males are called bulls.) Cows give birth to their calves after a nine-month gestation period. When this little calf (shown here at 10 days old) grows up, it may weigh up to a ton; its horns alone can grow to 2 feet long.
More bison photos after the jump!
-- Lindsay Barnett
Photos: Dieter Nagl / AFP/Getty Images