Dinosaurs Limb differences may explain the situation

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Dinosaurs Limb differences may explain the situation

Limb differences may explain the situation. Even the first dinosaurs had the fully erect, stiff-action limbs of the bird model. Early mammals retained less erect, more supple limbs. The latter did not bar mammals from big size, for many giant reptiles had sprawling limbs. But the dinosaurs’ stiff, birdy limbs may have made it difficult for them to deal with the increasing competition from mammals in the rough-terrain world of the small. Meanwhile, the more sprawling-limbed mammals could not make it against the erect-gait dinosaurs among the large. The dinosaurs’ ascendancy in big-animal roles was a triumph, but their inability to succeed as small animals may have been their eventual undoing, as we shall see below. Animatronic dinosaur

 

As the Mesozoic progressed, walking dinosaur costume why did mammals not develop fully erect limbs plus high-level warm-bloodedness-some Late Cretaceous herbivorous ungulate mammals did-and start competing with dinosaurs for the small-predator niches? After all, mammals have sophisticated, close-fitting permanent teeth; theropods’ were sloppy, replaceable Lizard-like amays. But it may be that finely sculpted mammalian teeth are not superior for predation. In fact, early mammals developed such precisely occluding teeth for chopping up little insects. Big mammalian carnivores did not develop sophisticated teeth for predation, they inherited them and had to modify them to the task. As a result, mammalian carnivores can deliver precision bites, but these may be no more efficient than the theropods’ slashing and cutting methods. Likewise, giant toothless predatory ground birds outcompeted complex-toothed marsupial predators in the South American Tertiary. Lacking any clear-cut advantage over theropods, Mesozoic mammals may never have been able to move into an arena dinosaurs had already mastered. animatronic dinosaur for sale