- Not all big prehistoric reptiles are dinosaurs.
- What defines a true dinosaur from the rest of reptiles, is the shape of its hips and legs.
- While most walking reptiles move as lizards do, with their legs holding up the body from its sides, dinosaurs walk with straight upright legs, that support the body as pillars.
- So, in simple words, if it swims, flies, or walks as a lizard, it is not a dinosaur.
- If it walks with two or four straight upright legs, it is a true dinosaur.
- Many dinosaurs developed internal heat, similar to mammals and birds.
- Many dinosaurs also developed feathers, to keep their heat inside the body.
- Some of these feathered dinosaurs eventually evolved into birds.
- While most dinosaurs got extinct after the KT event, birds survived until today.
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Triceratops skull; photo by Tiseb cc-by |
Velociraptor skeleton ; photo by Kabacchi cc-by |
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Sources:
-The Variety of Life, Colin Tudge, 2000
Citation: García, A.I. 2015. The Tree Of Nature (Online) at http://thetreeofnature.com