Before revision: Vertebrates (such as reptiles, some fish, and most birds) reproduce with internal fertilization through cloacal copulation (see also hemipenis), while placental mammals copulate by inserting the male's penis into the female's vagina .
After revision: Vertebrates reproduce with internal fertilization through cloacal copulation (in reptiles, some fish, and most birds) or ejaculation of semen through the(in mammals) penis into the female's vagina .