  Female blue whales can go into heat during any time of the year. However, it most often happens during migration into warmer climates, which is mating season. Sexual maturity is reached at five to ten years of age. Blue whales are dioecious meaning they have males and females in separate individuals. Mating usually occurs near the equator where it is warmer. Blue whales have a fairly intricate mating process of swimming around each other, diving deep down into the ocean, and when they swim up to the top of the waters, the mating process completes. Baby blue whales grow inside the uterus of the mother whale for 12 months. They grow rapidly-an inch a day after 3 months of pregnancy. The female blue whale gives birth to a single calf every two to three years. The blue whale is born weighing 6,000 pounds and swims for oxygen as soon as it is born. Blue whale birth usually occurs in the winter and spring time. At six months old the blue whale is, on average, 52 feet long. The baby blue whale stays with his mother for 6 to 12 months, eating 200 pounds of his mother's milk every day. Once full grown, the blue whale weighs on average 200,000 to 300,000 pounds. They are typically seventy to ninety feet long, but the longest has been recorded at 100 feet long. To put this into perspective, that is about three school busses long! The size of the blue whale's heart is about the same as a small vehicle. Blue whales are in the baleen whale family and are blue-grey in color. They get a yellow tint on their bellies from cold water diatoms attaching to their skin. This is how the blue whale gets the nickname "sulfur bottom" (Whitaker). |
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