In males, the urogenital opening is in front of, and separate from, the anus. The long retractable penis, which is normally wholly inside the body, is almost prehensile and emerges when erect. The paired testes are hidden deep within the abdominal cavity near the kidneys. Females also have a urogenital slit on the belly, within which both reproductive and excretory organs are located. The two mammary glands are located on either side of the urogenital opening, and the nipples are recessed within longitudinal slits. The nipples extend during suckling, and because the baby dolphin cannot actually form its mouth to suck, it forms a passage with it's tongue and the roof of it's mouth for the rich milk, which is squirted directly into the baby's mouth.