Dolphins are marine mammals whose reproductive cycle and the upbringing of their young involve unique biological and behavioral adaptations. A common question concerns the specific term used to refer to these remarkable young creatures. Understanding this name provides the starting point for exploring their early lives, physical development, and the deep maternal bonds that ensure their survival in the ocean.
The Official Terminology
The name for a baby dolphin is a “calf,” a term shared with many other large mammals that give birth to a single, dependent offspring. This designation is also used for the young of other cetaceans, such as whales, and land animals like cows, elephants, and giraffes. Female dolphins are known as “cows,” and males are called “bulls.” This terminology highlights that dolphins are warm-blooded mammals that nurse their young.
Size and Physical Characteristics at Birth
A dolphin calf is typically born tail-first, a delivery method that helps prevent the newborn from drowning during the birthing process in the water. Once delivered, the mother immediately guides the calf to the surface to take its first breath. A newborn common bottlenose dolphin calf generally measures between 3 to 4.5 feet in length and weighs approximately 22 to 44 pounds.
The calf’s dorsal fin and tail flukes are initially soft and pliable, allowing for easier passage through the birth canal, but they stiffen within a few days. Newborn calves often appear darker than adults and may display temporary vertical, light-colored lines on their sides, known as natal folds. These folds result from being tightly curled inside the mother’s womb and usually disappear within six months. Some calves are also born with fine hairs on their rostrum, or snout, which are quickly shed.
The Duration of Maternal Dependency
The mother-calf bond is extremely long-lasting, which is necessary for a species requiring a prolonged learning period for survival. Calves are dependent on their mothers for milk, nursing for anywhere from 18 months to up to two years, though some species may nurse longer. Dolphin milk is highly concentrated, containing high percentages of fat and protein to fuel the calf’s rapid growth in the cool ocean environment. The mother is able to eject this milk directly into the calf’s mouth when it positions itself near the mammary slits.
For the first few weeks, the calf swims in a position known as “echelon swimming,” tucked closely beside its mother’s body. This close proximity allows the calf to be carried along in the hydrodynamic wake, or slipstream, created by the mother’s movement, conserving the calf’s limited energy. This constant activity means the mother and calf are highly vigilant, often eliminating periods of rest at the surface for the first two months. The mother’s protection and guidance are gradually replaced by lessons in hunting and social skills, with the calf remaining closely associated with her for three to six years, depending on the species.