Given that blue whales are the largest animals on Earth, it’s no surprise that their offspring are massive at birth. Just how big is a baby blue whale? A baby blue whale calf measures nearly 25 feet long and can weigh up to 8,000 pounds! To put this size in perspective, that’s about the length of a city bus and the weight of a fully grown female African elephant.
Now that we’ve answered the question, “How big is a baby blue whale?” It’s time to ask another question: “Why are mother-calf blue whale pairs rarely spotted?”
While it would be a thrill to spot a baby blue whale surface from the ocean depths, it’s about as rare a sight as red sprite lightning, a mesmerizing atmospheric phenomenon that occurs high above thunderstorms and gives the appearance of vivid red jellyfish tentacles in the sky.
For decades, researchers have been trying to determine why baby whale calves aren’t more visible to us humans. Was it a matter of low fetal survival? Low birth rates? A study published in the latest volume of Endangered Species Research has put forth a new theory—and it might very well be the most credible one yet!
Knowing When to Look
Unlike women who are pregnant for approximately nine months and give birth throughout the year, female blue whales are pregnant for approximately one full year, and they give birth in remote waters between December and February, according to the Marine Mammal Center (MMC).
MMC also notes that when a baby blue whale is born, it begins nursing and gains up to 10 pounds an hour. This incredible speed of growth—with blue whale calf gaining up to 250 pounds a day—means that by the time it reaches six months old, it has doubled in size. Perhaps more importantly, the blue whale calf is now prepared to leave its mother’s side.
Trevor A. Branch, representing the University of Washington’s School of Aquatic and Fishery Sciences, theorizes in his study published by Endangered Species Research that the reason humans don’t readily spot blue whale calves has everything to do with the fact that we’re looking for these calves in easily accessible summer feeding areas. Based on the female blue whale’s birthing and weaning schedule, the calves have already separated from their mothers by then, making the opportunity to spot a mother-calf pair unlikely.
After observing blue whales in New Zealand, the Gulf of California, Timor Trough, the Galapagos, and Sri Lanka, Branch concluded that mother-calf proportions peaked not in the summer but in the winter. He writes, “The mystery of the missing blue whale calves can largely be explained by mothers calving immediately after leaving summer feeding grounds and weaning on their return.”
Branch’s theory not only reminds us of the distinctive reproduction cycle of female blue whales but also points out that the blue whale calf becomes independent at a young age. That baby blue whale we’re looking for is not with its mother; instead, it’s off on its own, gulping krill, vocalizing, and navigating its habitat.
Try to Spot a Blue Whale With Us!
While Harbor Breeze Cruises doesn’t guarantee sightings, we can confirm that we’ve been fortunate to spot blue whales May through November. Spotting a blue whale in its natural habitat is breathtaking. If you’re interested in trying to spot a blue whale with our captains, crew, and Aquarium of the Pacific educators, now’s a great time to purchase your tickets!
We look forward to welcoming you aboard our comfortable, eco-friendly catamarans. We’ll give you tips on how to spot a blue whale, answer any questions you may have about the ocean and marine life, and treat you to an exciting experience on the water. Tickets for our daily whale watching cruises can be purchased online or via phone by calling 562-983-6880.