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Apr 07

Four More Common Animal Misconceptions

One of the first articles I did for this blog was on animal misconceptions – that is, commonly believed facts about animals that are actually complete nonsense. I also wrote an article about the topic for the website TopTenz, which you can read here. But if there’s one thing I’ve learned about the natural world, it’s that there is never a shortage of facts that people frequently misquote…

1. Camels store water in their humps

We learn this often-repeated ‘fact’ from a young age, usually from relatives when we visit zoos. It comes from a time, not too long ago, when scientists actually did believe that camels stored water in their humps for long treks across the desert between drinking holes. Now we know – correctly – that camels store fat in their humps, not water (they store excess water in their bloodstream and in their stomach).

2011_Trampeltier_1528

Photo: J. Patrick Fischer

It’s sometimes easy to forget that food is just as scarce as water in a desert, so camels store reserves of fatty tissue within their humps for leaner times. The presence of a hump minimises the insulating effect the fat would have if it were distributed evenly over the animal’s body, helping the camel to survive in very hot climates.

2. Robins only come out in winter

The robin has a close association with Christmas and the winter season in general, and is often depicted on the front of Christmas cards. Some say that this relationship began because, according to legend at least, it was a robin who sang in Jesus’s ear to comfort him from his pain when he was dying on the cross. Back then, all robins were simply brown in colour, but the blood from Jesus’s wounds stained the bird’s breast red, and therefore all robins got the mark of Christ’s blood upon them.

The association with Christmas, however, more probably arose because postmen in Victorian Britain wore red uniforms and were nicknamed ‘robins’. The robin that was featured on the Christmas card was once the emblem of the postman delivering the card itself.

So now that we know the bird itself has no close ties to Christmas, it would certainly be a surprise if a small, non-migratory songbird only came out during winter – and that’s because it doesn’t. Robins are active all year round, but they are most commonly seen during the winter because there is fewer dense foliage to conceal them, and also because of the sharp contrast between their red breasts and the snow. In summer, there is an overabundance of other small active songbirds, so the robin doesn’t stand out as much.

But people used to have a different theory. Back before migration was widely known about, it was believed that the redstart, a summer visitor to Britain with an orange breast similar to the robin’s, turned into the robin when winter arrived and then back into a redstart upon the return of spring.

3. Goldfish have a three second memory

This is another firm assumption that seems to have popped up out of nowhere. Regardless of its origin, experiments have proved beyond a doubt that goldfish have memories that can span at least three months rather than three seconds. In 2003, at the University of Plymouth, goldfish were trained to push a lever to earn a food reward; when the lever was fixed to work for only one hour each day, the fish soon learned to push it at the correct time. For the rest of the day, they ignored it. They have also been shown to distinguish between different shapes, colours and sounds, and recent research suggests that they can even identity their owner.

4. Tyrannosaurus was the largest carnivorous dinosaur

Anyone who has watched Jurassic Park III (and actually remembered it) will be aware that the main predator of the film was Spinosaurus, a huge carnivore with a sail-like structure on its back said to surpass even the mighty Tyrannosaurus in size. When the film aired, some people actually complained that their beloved T-Rex had been replaced by a fake dinosaur that had been made up by the producers.

Spinosaurus_skeleton

Photo: Kabacchi

But Spinosaurus was indeed a real dinosaur, and its discovery in 1912 came only a few years after Tyrannosaurus itself was discovered. It wasn’t until much later, however, that paleontologists realised just how big Spinosaurus was. Tyrannosaurus measured over 12 metres in length, weighed up to 7.5 tonnes, and was certainly the largest predator in its environment in North America 65 million years ago.

Spinosaurus, on the other hand, lived roughly 30 million years earlier, this time in what is now North Africa. And it was significantly bigger than T-Rex. It is estimated to have reached 18 metres in length and was at least 10 tonnes, although some experts claim it could have weighed a whopping 20 tonnes! Nowadays, Spinosaurus is recognised as the largest land predator that has ever existed – until we find something else that surpasses it, of course.

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