Big animal problems and clever solutions

Being supersized brings problems, but nature finds a way to overcome them. Evolution is smart.

Ever wondered how giraffes avoid blood rushes to the head? Or how ginormous prehistoric birds stayed airborne?

For the answers to these and other mysteries, read on.

Elephants have cancer fighting DNA
Elephants have cancer fighting DNA

More cells more cancer?

Cancer occurs when cells grow the wrong way. It’s logical to think the more cells you have, the higher your risk of cancer. This doesn’t necessarily follow. Elephants and whales are much bigger than us, but much less likely to get cancer.

That’s despite having many more cells than humans do.

Scientists have found elephants and whales are less likely to get cancer because of their DNA. The simple reason is they have more tumour suppressing genes than we do.

To find out more:

Elephants have a secret weapon against cancer

Whales and dolphins can resist cancer and their DNA explains why

Too big to fly?

The largest flying bird of all time had a wingspan equal to that of a Harrier Jump Jet. So how did it get off the ground?

Pelagornis sandersi lived 25 million years ago. It was enormous but could glide for vast distances across the oceans, making use of uplifts of air.

Even though it was big, P. sandersi was relatively lightweight. That’s because it had hollow bones with millimetre thick walls and weighed less than an adult human.

To find out more, watch this Smithsonian Channel video on YouTube.

Why don’t giraffes faint?

When giraffes lower their heads, why doesn’t the blood rush in? Giraffes have an amazing network of blood vessels in their upper neck that stops excess blood flowing to the brain.

This network is called the rete mirabile, which means wonderful net in Latin.

Rete mirabile exist in some other animals. In whales the network helps with diving. It enables them to separate off skeletal muscle blood circulation and to direct oxygen stores to the heart and brain.

To find out more:

Cetaceans and thermoregulation

The cerebral blood supply in the giraffidae

Too heavy to hop?

Procoptodon goliah was the most heavily built kangaroo ever known. It was two metres tall, about the height of a modern red kangaroo, but weighed two and a half times as much.

Scientists think hopping would have put too much strain on the kangaroo’s tendons. But that didn’t matter. It got round the problem by walking on two feet like a human.

Fossil finds in Australia show that P. goliah was a successful species until its extinction 15,000 years ago.

To find out more:

Procoptodon goliah at the Australian Museum

Giant kangaroo walked on two feet

The lost giants that prowled the Australian wilderness

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