A female bullfrog can lay up to 20,000 eggs. Bullfrog tadpoles take up to a year to become a young frog. Males will stay behind and take care of the tadpoles. Males are territorial and will attack any animal, including their own kind, if they come near them. Bullfrogs can reduce the mosquito population. They do this by eating most of the mosquito's larvae. Bullfrogs do not move during the day, except if there is food nearby or when threatened.