Have you ever wondered why animals change their behavior at certain times? Or why do some species have physical characteristics that others do not? The answer is adaptation.
Animals living in harsh conditions will alter their behavior to adjust to changes in their environment. Some animals develop physical changes that make them better suited to their environment than animals with similar physical traits.
So, how and why do these adaptations occur? Read on to find out more.
What Is Adaptation?
The definition of the term ‘adaptation’ is:
Adaptation often describes changes to a species’ behavior or physical appearance in response to its environment. Hundreds of examples of transformation have allowed a species to survive in harsh climates, from snow-covered landscapes to dry sandy deserts.
Adaptation and evolution are sometimes confused. The process of an animal or species developing an adaptation is reversible. For instance, a species may begin to hibernate during cold winters, but they may hibernate for a shorter time or not hibernate during warmer winters.
Evolution, by contrast, is when a species changes to become a new species. Breeding with the original type/strain of the species would not result in viable offspring. For evolution to occur, adaptations also need to happen.
The best example is the Galapagos islands’ finches, observed by naturalist Charles Darwin in 1834. Darwin often referred to as the father of evolution, collected specimens of finches and returned them to England. With the help of ornithologist John Gould, they discovered that the finches were almost identical to mainland finch species but had a distinctly different beak shape.
This gave way to Darwin’s theory of natural selection and evolution. For the finches on the Galapagos islands to have evolved into a separate species, they first had to adapt. This occurred when finches with a slightly different beak shape mated and produced offspring with the same condition. This beak shape made them more efficient at foraging the available food on the island.
The birds with smaller beaks were found eating harder, so more birds with larger beaks were bred. Eventually, all the finches being born on the island had larger beaks, and at this point, adaptation had become evolution.
Darwin’s finches are not the only examples of physical adaptation beneficial for a species’ survival.
America’s bear species have adapted with thicker fur to survive cold winters. Not all bears have thick skin; some bear cubs are born with thinner coats than their littermates, just like some humans have thin hair, and others are wide. Thicker skin allows the bears to maintain a more stable body temperature during the winter.
Some animals have a fur cycle. Horses, deer, and elk all grow thick winter coats to keep them warm during the cold weather. They then have a molting season when the days get longer at the beginning of winter. A second molting season happens at the end of summer to make way for the new winter coat to grow through again.
The winter coat may be slightly darker as sunlight is absorbed better by darker shades. Having lighter, thinner skin during summer prevents the animal from overheating.
Seals, sea lions, and walruses also show physical adaptations. Walruses and some seal species feed off the seafloor and have adapted to their environment by growing long whiskers. Their sensitive whiskers help them detect changes in the water current caused by fish or other prey animals swimming nearby.
American beavers have several physical adaptations to living in an aquatic environment. When a beaver submerges, they close skin flaps in its nose and ears to prevent water from getting in. they also have a similar appendage in its mouth that stops them from drowning when swimming with sticks in the water.
This is especially useful as a large part of a beaver’s dam is built underwater. Beavers also have webbed feet, which gives them better propulsion when swimming. Their paddle-like, flat tail has a similar effect, acting as the rudder of a boat. They also slap their seats on the water to warn other beavers of potential danger.
An animal may show behavioral adaptations in response to changes in its environment. In Juneau, Alaska, a wild wolf approached a photographer and his pet Labrador one day as they walked in a glacial park near the photographer’s home.
His Labrador immediately greeted the wolf, with the photographer fearing for his dog’s safety. However, the dog and wolf interacted just as the two dogs would. This is because dogs and wolves are closely related and share the same communication cues. Wolf and dogs both use body language signals, so the two can quickly determine the intent of the other.
After a while, the wolf appeared daily and even started interacting with other dogs and their owners when they came to the park for walks. It is believed that the wolf had lost his pack and had chosen to interact with the dogs due to a need for socialization.
This behavior continued for six years until the wolf, named by locals as Romeo, was shot by out-of-state poachers. Romeo’s behavior was an adaptation to the fact that he had no pack of his own. Changing his behavior to interact with dogs and humans was a positive choice because he gained social benefits. He still hunted alone and left each day to find a safe place to sleep, but he would also return to play with the dogs during the day.
Hibernation is a behavioral adaptation. There are two forms; traditional hibernation and torpor. In traditional hibernation, the animal will choose a safe place like a den and sleep right through winter, waking up at the beginning of spring.
Torpor is a mild form of hibernation, where the animal enters deep sleep but will wake every few days or weeks to find food and water. Hummingbirds enter torpor each night to avoid the need to eat. Their bodies are so small that they must consume nectar and catch insects every couple hours. Their heart rate and metabolism slow down during torpor, meaning they use less energy and do not need to eat.
It has been observed in several hibernating species that their pattern of hibernation changes with the severity of the winter weather. When the winter is mild such as warmer weather or less snow, the animals will enter hibernation later in the year and wake up earlier. If the winter months are gentle enough that there is still plenty of food available, animals may choose not to hibernate.
Migration is another example of behavioral adaptation. Those animals that do not hibernate will choose to move somewhere else. Like many people who have holiday homes in warm countries, many animals will travel south at the end of September or October, heading for countries with warm winter weather.
These mobile homes have a good food supply, and the climate is better suited. Migrating animals do not stay here because they have to compete with native species. They time their return home with the start of spring when vegetation begins to bloom and animals are ready to give birth. Springtime is also when the days get longer and the weather starts to warm.
Anyone who has kept koi fish knows that their behavior changes during winter. Even if ponds do not ice over, koi become less active and spend most of their time at the bottom of the pond. This is because the water is slightly warmer at the bottom, and by becoming less active, they use less energy.
Changes in behavior are all about surviving harsh conditions. This could be the weather, a fall in food sources, or human encroachment. Animals that do not adapt quickly usually die. This means only the animals can adapt and pass their genes to future generations.
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Bryan Harding is a member of the American Society of Mammalogists and a member of the American Birding Association. Bryan is especially fond of mammals and has studied and worked with them around the world. Bryan serves as owner, writer, and publisher of North American Nature.