In addition to true predators, many other animals have a predatory streak. They include omnivores with wide-ranging diets, as well as parasites, blood-feeders, and animals that scavenge dead remains. All these get their food wholly or partly from animals, but true predators are the only ones that must kill to survive.
Evolution does not move in any set direction. If conditions are stable, some animals may stay the same for millions of years. However, predators often grow larger during evolution, and sometimes evolve to extreme sizes.
Apart from cheetahs, most cats stalk their prey at dusk and after dark. Like many mammalian canivores, they have a reflective layer behind their eyes, which improves their vision when the light level is low.
Some insects and spiders can go for a year without eating. Being cold-blooded, their bodies need little energy, except for when they breed. Many other cold-blooded predators eat more often, either because they are bigger, or because they spend more time on the move. Even so, a meal often lasts them for weeks or days.
Predators have 2 main ways of catching food. Some hide and wait for prey to come their way, while others use speed to make a kill. Sitting and waiting uses much less energy, but high-speed predators usually manage to get more food.
These bursts push their bodies to their limits, which is why no hunter works at peak performance for long.
From the moment it is born, a snake or shark knows how to hunt, even though it has never seen prey before. Birds and mammals are different. Predatory ones inherit some hunting instincts, but learning plays a key role in their lives.
Lion hunts are most successful on dark, moonless nights as compared to the moonlit ones, since they cannot be spotted easily by their prey.
Spotted hyenas swallow practically anything they can tear off and swallow, including teeth, bones, and pieces of dried-out skin. They digest all this with their powerful stomach acids — a talent that few other scavengers can match.
Plants don’t need food, but they do need simple chemical nutrients to grow. Most get these nutrients from the soil. But where the soil is poor or waterlogged, carnivorous or predatory plants use insects and animals, catching them with strangely shaped traps.