Sink or Swim
7 September 2024
SINK OR SWIM? If you want to see a deep-water shipwreck, you are going to
In the Giants issue of AQUILA we took a look at the Antarctic blue whale’s unlikely comeback. Once abundant across the world’s oceans, commercial hunting took the blue whale’s population down to a critically endangered level. Thankfully though, numbers are starting to creep up again – albeit very slowly. Let’s take a closer look at the most MASSIVE living species on our amazing planet.
Weighing in at around 200 tons, the blue whale is a proper GIANT! Did you know, its tongue can weigh as much as an adult male lion? Or that its heart is the size of a small golf buggy? Well, you do now! And, in keeping with their parents’ colossal size, newborn calves are the biggest babies on the planet – they’re already around seven metres in length at birth. In their first year, they can grow up to 90 kg PER DAY – if you drank up to 180 litres of milk a day, maybe you could too!
That’s… that’s not how it works.
Blue whales may have the biggest hearts in the animal kingdom, but they beat very slowly! When swimming at the water’s surface, a blue’s heart beats at around 30 bpm. That may not sound too unusual, BUT this can slow right down to an impressive 4–8 bpm when diving to depths of more than 1,000 metres. The blue’s aorta (the largest artery of the body), is also a thing of worldly wonder! Its diameter is around the size of the average dinner plate. Don’t fancy drinking a milkshake through it though, do you? Ed.
A blue whale’s heart pumps around 220 litres of blood around its body on each beat!
Blue whales are known for their song. They have the loudest voices on Earth. Male blues sing to attract a mate, and females sing to their calves (aaaawww!). But did you know that the blue whale’s song is getting deeper? Since the 1960s their songs have shifted down about three white keys on a piano, and scientists don’t know why. Theories range from depressing, to slightly happier. It’s possible that their voices need to be deeper in order to hear each other over man-made noises, such as motorboats; and in slightly happier theories, it’s also possible that the whales’ slow population increase means they don’t have to shout anymore. Whale songs are getting deeper across all populations, however, regardless of whether there’s been a significant increase in numbers, so the plot thickens.
We all know whales have blow holes on the tops of their heads, right? But some species – the blue whale included – have two! It is basically a nose. Millions of years ago, these holes would have been snouts, but slowly they’ve moved to the top of the head to allow the whale to intake air when they come to the surface. Imagine if our noses were on top of our heads. How would our glasses stay on? Ed. Once the whale has taken a breath, a strong muscle seals the hole. This means that water doesn’t get into their lungs when they submerge. Yep, that’s right – that’s not usually seawater you see spraying out of a whale’s blowhole in those iconic photographs and vids, it is actually air (and snot).
There are two types of whales – baleen and toothed. You may think that in order to get to the size that they are, blue whales would need some enormous gnashers. After all, they must munch their way through loads of food to grow so big, right? Wrong. That couldn’t be further from the truth, actually. Blue whales fall into the baleen category. This means that, instead of teeth, blues have a fibrous plate which allows them to filter their food. Blues consume around 3,600 kg of krill each day – that’s around 40 million of the little blighters!
Not content with being the biggest animal on Earth, the blue whale is also one of the fastest animals in the sea, cruising at a top speed of 20 knots (37 kph)!
We hope you’ve enjoyed our brill (or should that be krill?!) blue whale facts – talk about a deep dive! For more fun facts, perplexing puzzles, cool craft and exciting experiments – with a smattering of high-jinx – subscribe to AQUILA today by clicking here!
Words: Benita Estevez
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