Whales are magnificent marine mammals, inspiring awe with their immense size and complex behaviors. The journey of their young, from birth to independence, is particularly intriguing.
Identifying Young Whales
Young whales are universally referred to as “calves.” This term applies to all whale species, from the enormous blue whale to the smaller beluga. “Calf” is also used for the young of many large mammals, including cows, elephants, and hippos, reflecting a shared linguistic convention for the offspring of sizable animals.
The Journey of a Whale Calf
Whale calves are born underwater, typically tail-first to prevent drowning. Immediately after birth, the mother helps her newborn reach the surface for its first breath. Calves are capable swimmers from birth, though they remain close to their mothers for protection and nursing.
Nursing occurs underwater, with the calf stimulating mammary glands concealed within slits on the mother’s belly. The mother injects thick, high-fat milk directly into the calf’s mouth; whale milk can be 35% to 50% fat, similar to toothpaste in consistency.
This nutrient-rich milk supports rapid growth; a blue whale calf can gain up to 90 kg (200 lbs) per day, and humpback whale calves drink hundreds of liters daily. This rapid weight gain is essential for developing a thick blubber layer, which provides insulation in cold ocean waters.
Nurturing and Protection
A strong bond exists between a mother whale and her calf. Mothers dedicate significant time and energy to raising their young, often positioning the calf close to their side while swimming, a position known as “echelon.” This allows the calf to conserve energy by taking advantage of the mother’s wake.
This close proximity is also a primary defense mechanism against predators. Mothers use their large bodies to shield their offspring, sometimes forming defensive circles with other whales, tails outward, to deter threats.
Calves learn essential survival skills from their mothers, including navigation, communication, and foraging techniques. For example, humpback mothers have been observed teaching their calves how to breach.
The duration a calf stays with its mother varies by species, ranging from several months to a few years; humpback calves typically stay for about a year, while orca calves may remain with their mothers for life. This extended period of maternal care is crucial for the calf’s development and independence.
Challenges for Young Whales
Young whales face numerous threats. Natural predators include orcas, which target whale calves, and large sharks. Orcas may work in groups to separate a calf from its mother, and sharks often prey on young, sick, or injured whales.
Human activities also pose dangers. Ship strikes are a threat, particularly for young whales less adept at avoiding large vessels. Entanglement in fishing gear, such as ropes and nets, can cause severe injuries, impede feeding and movement, and lead to death. Calves are particularly vulnerable.
Noise pollution from shipping and other human activities can disrupt whale communication and navigation. Climate change presents a challenge, as rising ocean temperatures and altered prey distribution can reduce food availability, affecting a mother’s ability to nourish her calf and impacting calf survival rates.