Why do animals have different behaviors?
There are several broad categories that behaviors fit into based on what benefits the behaviors give the animal. Some behaviors allow animals to forage (collect food). Other behaviors allow animals to find mates, and still other behaviors allow animals to escape from predators. In this section, we will go over some of these general types of behaviors and some interesting examples of each.
Escaping from predators
One of the most important behaviors an animal can do is avoid getting eaten. There are several tricks that animals use to avoid getting eaten. One trick is to blend in with the background. Many animals have coloration that can allow them to blend in with their surroundings. This is called cryptic coloration. Sometimes, animals move to areas where they can blend in. For instance, stick bugs tend to stay around sticks instead of crawling on leafs where they would be more conspicuous. Other animals can change their coloration to match the environment they're in. Take a look at the video on the right as an octopus changes color to blend in with the coral reef.
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Sometimes animals will try to hide in or under things, instead of changing their coloration. Take a look at this slow motion video of a flatfish burying in the sand. This flatfish undulates its body, flinging sand into the water column. The sand then settles on top of the fish, burying it completely. If a potential predator came near this flatfish, it might pass right on by, seeing nothing but sand. Read more about how flatfish bury themselves here.
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Another way that animals use coloration to avoid being eaten is to flash warning colors. These are bright, showy colors that tell a predator, "I'm poisonous! Don't eat me!" This type of coloration is called aposematic coloration. Sometimes animals will change their coloration to an aposematic coloration, like squid. But generally, they simply display an area that is always brightly colored. The frill necked lizard to the right only displays it's bright orange frill when it feels threatened. This frill has the added benefit of making the lizard look larger than it is, which might make it harder to eat. Many animals will try to look as large as they can when they are threatened for the same reason.
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If hiding and displaying do not work, an animal may have no choice but to run away. This is called an escape behavior and it varies widely by species. Fish have a characteristic c-start escape response where they curl their bodies into a c-shape and then swim away from the predator in the opposite direction. Birds fly away rapidly if they are on the ground, or dive into trees if they are already in the air. On land, high speed chases can ensue, as demonstrated by this gazelle running from a cheetah. In all cases, if the prey animal can start escaping quickly, it has a higher chance of surviving the encounter. This is why many animals are always paying attention to their surroundings, in case there is a predator nearby.
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Foraging for food
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In addition to avoiding becoming someone else's food, animals engage in behaviors that allow them to find and catch their own food. The first step in eating for an animal is to find food, a behavior called foraging. There are at least as many different behaviors dedicated to this task as there are different foods for animals to eat. An animal that eats grasses will have very different foraging behaviors from an animal that eats deer or an animal that eats fish. Some animals, like predatory snails and moles, follow chemical cues (scents) to find their food. Other animals, like humpback whales, migrate long distances from mating grounds to feeding grounds every year. Still other animals sit and wait for prey to wander past them, like ornate horned frogs, or even try to lure prey in using ornaments, like anglerfish. Many grazing species, like cows and horses, travel from patch of grass to patch of grass, eating as they go.
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Finding a mate
If an animal can get enough food to grow up without becoming food itself, it has achieved a lot. But there is one more challenge that animals must overcome; they must find a mate and produce offspring. If animals didn't succeed at finding a mate and having babies, they would quickly become extinct (die out). There are several challenges to finding a mate. Sometimes, animals are so spread out that it's difficult to find another individual of the same species at all. This is the case with the anglerfish. It is so hard for anglerfish to even find each other in the deep ocean that when they do, the male fuses with the female so they never get separated. The picture to the right shows a female anglerfish with many males fused to her.
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Often, animals want to find the absolute best mate, so they will refuse to mate with individuals that don't meet their standards. This is called mate choice, and it is usually the females of the species that are choosier than the males. Because of this, males will compete for the attention of the females, called male-male competition. This can take the form of elaborate shows, like the birds of paradise which performs a dance to attract a mate, or of building elaborate nests to attract a female, like the bower bird which collects blue material to put in his nest. Sometimes males will compete in fights like moose or hold large territories like lions. In each of these cases, the males that compete the best tend to get the best mates.
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One thing that animals generally try to avoid is inbreeding or mating with relatives. Inbreeding can have very bad effects and reduce the ability of the offspring to survive. Individuals not only try to avoid inbreeding themselves, but there is also evidence they try to avoid mating with inbred individuals. Learn more about how fruit flies avoid inbreeding here.
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Moving Around
A key aspect of most animals' lives is locomotion, or moving around. Our locomotion usually involves walking or running. This is called bipedal locomotion because we use two feet. Your dog uses a form of locomotion that involves four feet called quadripedal locomotion. How would you get around if you only had one foot, like a snail? Would you hop? It turns out that snails have two types of locomotion, one where they glide, called adhesive crawling, and one where they take steps, called loping. To learn more about snail locomotion, click here. What would an animal with no feet do? Consider the snake to the left. How does it move? Think about how animals that live in the water or fly through the air or dig in the ground would have different types of locomotion.
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