Pygmy blue whale facts for kids
Quick facts for kids Pygmy Blue Whale |
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B. m. brevicauda
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| Balaenoptera musculus brevicauda Ichihara, 1966
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The pygmy blue whale (Balaenoptera musculus brevicauda) is a special type of blue whale. You can find these amazing creatures in the Indian Ocean and the southern Pacific Ocean.
Even though it's called "pygmy," it's still a huge animal! It can grow up to 24 meters (79 feet) long. That's about as long as two school buses! It's smaller than other blue whale types, which can reach 28 to 30 meters (92 to 98 feet). That's why it got its "pygmy" name.
Unlike other blue whales, pygmy blue whales often live in warm, tropical waters. They travel from the cold sub-Antarctic areas to the warmer Indian and southwestern Pacific Oceans. They breed in the Indian and South Atlantic oceans. Then, they swim south to feed near the Antarctic, but they rarely go too far into the coldest waters.
Scientists once thought there was another type of blue whale called B. m. indica. But now, they believe it's actually the same as the pygmy blue whale. Pygmy blue whales might be more common than other blue whale types. They could make up half of all blue whales alive today.
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What Makes Pygmy Blue Whales Special?
Since scientists first described them in 1966, we've learned that pygmy blue whales look a bit different from other blue whales.
Here are some of their unique features:
- They have baleen plates that are wider and shorter. Baleen plates are like giant combs in their mouths that help them filter tiny food from the water.
- Their tails are shorter. This means the front part of their body, before the dorsal fin, looks longer.
- Their heads are bigger compared to their body size.
- They weigh more than other blue whales of the same length.
Size and Weight of Pygmy Blue Whales
Pygmy blue whales become adults when they are about 10 years old. At this age, they are usually around 19.2 meters (63 feet) long. They weigh about 52.5 tonnes (58 tons).
Adult males are typically 21.1 meters (69 feet) long. Adult females are a bit longer, averaging 21.9 meters (72 feet). Most adult pygmy blue whales are between 20.7 and 22.5 meters (68 and 74 feet) long. Males weigh about 75.5 tonnes (83.5 tons), and females weigh around 90 tonnes (99 tons). A very large pygmy blue whale, reaching 79 feet, could weigh as much as 129.5 tonnes (143 tons)!
How They Dive and Look
Because of their shorter tails, pygmy blue whales have a shape that looks a bit like a tadpole. This also changes how they dive. When other blue whales dive, their dorsal fin and the part of their body near the tail (called the caudal peduncle) go under the water at different times. But with pygmy blue whales, both parts go under at the same time.
Pygmy blue whales also tend to be darker in color than other blue whales. Even the shape of their blowhole, which they use to breathe, is different!
How Pygmy Blue Whales Evolved
Pygmy blue whales came from a group of Antarctic blue whales about 20,000 years ago. This was around the time of the Last Glacial Maximum, when a lot of the Earth was covered in ice. The ice likely pushed blue whales further north. Some of them stayed in those warmer areas, leading to the pygmy blue whale we see today. Because they are a newer type of whale, they don't have as much genetic variety as older types.
Protecting Pygmy Blue Whales
The pygmy blue whale is part of an important agreement called the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region (Pacific Cetaceans MOU). This agreement helps protect whales and dolphins in the Pacific Islands.
