Blue Whale Calves Gain Hundreds of Pounds Daily

From their gargantuan size to their voracious appetites, blue whale calves never cease to inspire wonder. Perhaps the most incredible aspect of the blue whale’s life cycle is the astonishing rate at which the calves put on weight in the early stages of life. In the span of just a few months, a blue whale calf can balloon in size, transforming from a sizable newborn into a true leviathan of the deep.

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Mama blue whale, ID 152597313, © Anne Webber|

Birthing Blue Whale Calves

When a mother blue whale gives birth, her newborn calf is already an impressive size. Weighing in at around 3 tons (that’s equal to 3 adult polar bears or 18 big football players!) and measuring up to 23 feet long, these babies are indeed giants in their own right. This remarkable size is the result of a lengthy gestation period. Blue whale pregnancies last approximately 12 months. During this time, the unborn calf steadily grows, fueled by the rich nutrients provided by its mother.

Nursing and Rapid Weight Gain

The blue whale calf wastes no time in capitalizing on its mother’s bountiful milk supply. The mother whale ensures her offspring is well-nourished and ready to pack on the pounds by producing over 50 gallons of high-fat milk per day. In fact, the calf can gain an astounding 200 to 250 pounds every single day during the first 6 to 12 months of nursing. This equates to a weight increase of around 10 pounds per hour, as the calf consumes nothing but its mother’s milk.

Transitioning to Krill

After the initial nursing period, the blue whale calf is weaned off its mother’s milk and begins to transition to a diet of krill. These tiny crustaceans make up the primary food source for adult blue whales. They have evolved a unique feeding mechanism to filter and consume these abundant marine creatures efficiently. Using their baleen plates, blue whales can swallow up to 50 gallons of water at once, trapping the krill inside their mouths and expelling the excess water.

Achieving Mammoth Proportions

The blue whale’s prodigious appetite, from infancy through adulthood, is what allows it to reach its legendary size. While a newborn calf may weigh 3 tons, an adult blue whale can tip the scales at a staggering 200 tons – more than 50 times its birth weight. That’s 1,200 big football players or 10 commercial jets. To put this into more perspective, the largest land mammal, the African elephant, weighs about as much as a blue whale’s tongue. 

Pleated Throats and Expandable Mouths

The blue whale’s feeding process is further enhanced by the presence of pleats, or grooves, on the underside of its mouth. These pleats allow the whale’s mouth to open incredibly wide, accommodating the enormous volume of water the animal takes in during a single gulp. The pleats stretch and expand, enabling the whale to engulf a volume of water greater than its own body size.

Breathing Adaptations

The blue whale’s size is not the only remarkable aspect of its physiology. These giants have also evolved specialized adaptations to support their ocean lifestyle. For example, their dual blowholes allow them to breathe while only the top of their head is above the water’s surface. Before diving back underwater, a flap covers the blowholes, sealing them shut to prevent water from entering.

Whale Calls and Vocalizations

Blue whales are known for their incredible vocalizations, which are some of the loudest sounds produced by any living creature. Their low-frequency calls, which can travel hundreds of miles through the open ocean, have been recorded at up to 188 decibels – a volume comparable to a jet engine. These haunting, rumbling sounds serve as a means of communication and navigation for these massive marine mammals.

Habitat and Migration Patterns

The blue whale’s range is extensive, spanning all the world’s major oceans, from the poles to the tropics. These whales often hang out in open waters, but they may also be found near icebreaks, islands, and seamounts. Blue whales typically undertake long annual migrations, moving from areas closer to the equator in the winter to higher-latitude regions, such as the Arctic or Antarctica, in the summer months.

Conservation Challenges

Despite their sheer size and power, blue whales have faced significant challenges due to human activities. In the early 20th century, intensive whaling operations decimated the global blue whale population. The blue whale population was reduced from an estimated 350,000 individuals to just 1,000 by the mid-1920s. While the species has since been granted protected status, the blue whale remains classified as “Endangered” on the IUCN Red List. The ongoing threats and challenges include entanglement in fishing gear, ship strikes, and the impacts of climate change on their primary food source, krill.