Sharks are more ancient than dinosaurs

Sharks are fish which have cartilages rather than bones. These fish evolved earlier than dinosaurs, which were reptiles. The fossil records show that sharks existed about 400 million years ago. Dinosaurs were found during the Triassic period, i.e. about 225 million years ago.

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The earliest known bird

The archaeopteryx is considered to be the earliest bird and it is the link between birds and reptiles. The archaeopteryx had a set of teeth, which are not found in birds. However it had wings, feathers and reduced fingers, all found in modern birds.

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Tooth regeneration in crocodiles

Crocodiles have 24 sharp teeth on each jaw, which are meant to grasp and crush, not  to  chew.  The  teeth are continuously replaced during a crocodile’s lifetime. Each tooth is hollow, and a new tooth grows inside the old one in order to be ready once the old tooth is lost. Young crocodiles can replace their teeth at a rate of one new tooth per socket each month.

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