Animals that stay active in winter need to be able to move about to find food and shelter. Read about some examples of adaptations that help animals get around in snowy places.
If you live in a place where snow builds up on the ground during the winter, you have probably experienced stepping into the snow and sinking. It is hard to walk in deep snow, and it takes a lot of energy! Thousands of years ago, people invented snowshoes, which allow a person to stay on top of soft snow by spreading out his or her body weight over a larger surface area. Although you might still sink into fluffy snow a little bit when wearing snowshoes, you will sink much deeper without them!
Where did humans get the idea for creating snowshoes? We can’t be sure, but it is possible that they observed how animals such as snowshoe hares and lynx are able to travel on top of soft snow due to their large feet. A snowshoe hare’s hind feet are 4-6 inches long on average, which is small compared to a person’s foot, but huge compared to the size (about 20 inches long) and weight (about 3-4 pounds) of a hare’s body.
The lynx, a predatory wild cat of the north, also has large feet relative to its body weight, providing it the ability to stay near the surface of the snow. Instead of helping it to avoid predators, however, the lynx’s large feet help it to effectively hunt other animals, especially the snowshoe hare. Over generations, animals such as snowshoe hares and lynx have evolved to have large feet through the process of natural selection, by which animals who were better able to travel in and on snow experienced greater survival and were therefore able to produce more young with similar traits.
Caribou feet – a traveling tool kit!
A caribou’s foot is the ultimate snow tool; it is a snowshoe, traction device, and shovel all in one (well, all in four). Their large foot size isn’t as obvious as it is in the hare or lynx, but they are much larger in relation to their body weight than are other northern-dwelling members of the deer family, including moose and elk in North America. Feet of elk and caribou are about the same size, but elk weigh two to three times as much as caribou!
The bottom of caribou feet are covered with fur, which not only helps to keep them warm but also provides traction on ice and slippery snow. They also use their large, curved hooves like shovels to dig into the snow to get to the lichen (a low-growing, plant-like organism) that provide the bulk of their diet in the wintertime.
Moose, which live in northern climates, have a different adaptation for getting around in snow. They are tall – 6 to 7 feet tall at shoulder height – and they have very long legs. Their long legs allow them to walk in snow without getting stuck. For example, imagine a short person and tall person trying to walk through the snow together. With two feet of snow on the ground, the short person might be up to their thighs in snow, while the snow might only reach the taller person’s knees. Which person do you think will have an easier time moving around in the snow? The moose is the equivalent of the taller person, and a shorter-legged animal such as a wolf is the equivalent of the shorter person.
On the other hand, wolves weigh much less than moose, and therefore they don’t sink as much in the snow. The amount of snow on the ground can have a big effect on the balance between predators and prey in a given winter by determining which animals are at a greater advantage for getting around.