Other roaches are ovoviviparous. Rather than growing in an ootheca outside of the mother's body, the roaches grow in an ootheca inside the mother's body. In a few species, the eggs grow inside the mother's uterus without being surrounded by an ootheca. The developing roaches inside feed on the eggs' yolks, just as they would if the eggs were outside the body. One species is viviparous -- its young develop in fluid in the mother's uterus the way most mammals do. Ovoviviparous and viviparous species give birth to live young.