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Showing posts with label crocodile. Show all posts
Showing posts with label crocodile. Show all posts

Strange Animals Live in Australia

If you want to see weird animals go visit Australia. Most animals are spread throughout the world but Australian marsupials stay strictly at home on this "lost continent". Two hundred kinds of marsupials live only in Australia the kangaroo being the most commonly known.

When the platypus was first taken to England scientists of the day said it was a hoax, a made up animal. The koala seemed to be a cuddly bear. Unfortunately wild koalas can be very nasty and do not take kindly to being picked up. So aligned to its environment, the Tasmanian Tiger soon became extinct with the arrival of Europeans.

Besides marsupials, other creatures make life difficult for people living on this continent. Red back and funnel web spiders are dangerous. The box jellyfish also causes much pain to humans. Small animals have died from their sting. Don't let the presence of these put you off from a visit to this great country. Oh, I nearly forgot; crocodile lives up north.
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Nature
Australian Blog                        
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No Scales on a Crocodile's Head

Contrary to popular belief crocodiles don't have scales on their heads. They are just cracks in the thick skin on their skulls. The rest of the body does have scales. How the animal develops biologically is interesting. Each scale forms from a discrete scale primordium. For example, scales at similar points each side of the body are identical.

The deep lines on the head are unique to each crocodile, like a fingerprint. Indeed, the lines are not symmetrical. Now it is possible to identify young crocodiles without tagging, to follow their growth.

Having no primordia on a crocodile's head is functional. Mounds of skin build up and form an active memrocobrane. Receptors detect fine vibrations in water. This helps in hunting.

It has been hypothesised that fingerprints form in the same way as the "cracks" on the heads of crocodiles. This unregulated gene formation building on earlier skin development is probably the reason why identical twins have different fingerprints. The final shape of all creatures was believed to be totally preprogrammed by genes.
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Genetics
TwitThis
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