Dolphins have two mammary slits on their underside, with an inverted nipple inside. The nipples do not protrude the same as terrestrial mammals, and young dolphins can not feed at any time as land mammals can. When the calf is ready to feed, they dive underneath the mother and nudge the mammary slits.

Unlike their terrestrial counterparts, dolphins do not possess visible nipples. Instead, they have evolved an extraordinary feature known as “ mammary slits.” These discreet openings house the mammary glands, crucial for feeding their calves.

Whale and dolphin calves take frequent short dives beneath the mother for nursing. Whales and dolphins do not have external nipples, instead their nipples are enclosed within mammary slits. Upon stimulation of the calves nudging, the nipple is exposed and the calf positions itself such that the nipple is at the gape of the calf’s jaw for feeding.