A Dolphin Calf's Milestones

From the first seconds through the first 12 months of a Pacific white-sided dolphin’s life, survival hinges on its ability to pass a set order of critical milestones. Achieving some of these milestones seems all the more amazing because the calf is an air-breathing mammal born in a cold underwater environment.

Birth

Milestone 1: Birth

Evolution has taken advantage of that cold water to literally give a newborn dolphin a “leg up.” If the calf is born tail first, during the hours of labor, its rolled-up flukes unfurl and harden in the cold water. After the calf clears the birth canal, its first move, if healthy and strong, is to pump that tail to reach its second milestone.

Breath

Milestone 2: Taking a first breath

Within moments of birth, and sometimes with the help of its mother, the calf wriggles its 3-foot body to the water’s surface to fill its lungs for the first time.

Bonding

Milestone 3: Bonding with mom

The calf has to recognize mom as its protector and life-support system, and start swimming and bonding with her. It also has to find those hydrodynamic areas along her body that will allow it to slipstream, or be drawn along in her wake, conserving its energy.

Nursing

Milestone 4: Nursing

This is the toughest milestone. Until the calf begins to nurse, it’s burning through limited energy reserves. So the clock is ticking. But in an instinctive quest for food, the calf searches for its mother’s mammary glands, which are recessed and near her tail. And the calf has to do it while both are swimming. An experienced mother might tilt her body so that the exploring calf finds its way to the right spot. But it’s not over. Mom has to produce milk in sufficient quantities, and the calf has to become proficient at nursing. The nutrient-rich milk from the mother is loaded with fat that helps the calf gain weight.

Growth

Milestone 5: Growing

So far, the calf has survived. Now it’s time to thrive. When the calf is hungry, it bumps mom’s underside, which stimulates milk flow, and it latches on. Early on, the calf might nurse a couple of minutes every half hour, but as it becomes more proficient, it can get more milk in less time and fewer nursing sessions. The calf’s fetal folds—the small indentations in its sides left over from being curled in mother’s womb—begin to fill out, a sure sign that it’s gaining weight and growing. Week by week, the calf becomes rounder and longer.

Fish

Milestone 6: Discovering fish

Between 1 and 3 months old, the calf starts to take an interest in the fish mom eats. At first, fish are new toys to mouth and flip around. But soon or later, the calf swallows one and might notice that it tastes good going down. The timing coincides with the calf’s digestive development, and it begins the gradual transition from nursing to eating solid food. During that time, it’s getting a super-high-protein diet of milk and fish, which supports its rapid growth.

Weaning

Milestone 7: Weaning

The calf is fully weaned between 12 and 18 months old. (Another milestone, the first birthday, is the criterion for a successful birth.) This final milestone not only marks the calf’s graduation to an adult diet but also its independence from its mother.