Читать книгу Dinosaurs - Douglas Palmer - Страница 9

Much of our understanding of dinosaur behaviour is based on our knowledge of their body form and feeding habits – whether they were plant eaters (herbivores) or meat eaters (carnivores). Knowledge of how different kinds of living plant eaters interact with their meat-eating predators can give insights into how the dinosaurs interacted. Like herbivorous mammals today, many plant-eating dinosaurs tended to have good senses of sight, smell and hearing. To escape their predators, some were slimly built and fleet of foot. Others had heavy defensive armour and yet others sought safety in numbers. The meat eaters were well equipped with offensive weapons such as large, sharp teeth and claws, and were either fast on their feet, large and stealthy or good ambush hunters.

The study of dinosaur feeding behaviour was originally based on that of large living reptiles such as crocodiles. However, this was somewhat misleading as crocodiles, with their relatively small limbs, largely live in water and can survive on infrequent feeds. Relating other aspects of crocodile behaviour to dinosaurs proved equally mistaken. Crocodiles, for example, belong to the group of animals known as ectotherms, which rely on the sun’s rays to heat their bodies. In contrast, endotherms (which include mammals) use energy from frequent supplies of nutritious food and complex blood systems to maintain a relatively high body temperature. It was once thought that all dinosaurs were crocodile-like ectotherms, but we now know from several different lines of evidence, such as their bone structure, that some dinosaurs may have been endotherms. Consequently, their levels of activity and feeding were probably more like those of mammals than ectothermic reptiles living today.

We can now envisage many land-living predatory dinosaurs as active hunters that could run at speeds of up to 40kph (25mph) to catch their prey. Some predators may even have worked together in groups to kill prey larger than themselves, and some were cannibals. Many of the larger herbivores lived in herds so that their many combined eyes, ears and nostrils could provide early warning of approaching predators. But how do we know what dinosaurs ate?

Caption:

Pelecanimimus had a relatively large brain and unusually small teeth.