Winter can be an unpredictable season in Iowa. From blue skies to blizzards and everything in between, it can be tough to know just what to wear some days to keep warm. People can easily change their clothes, though, to match the weather.
The farm animals at the museum can’t put on a winter jacket and a stocking hat when it’s especially cold or a light sweater when it’s mild, and they certainly can’t come inside the house when it’s just too cold. So, what do they do instead to deal with Iowa’s unpredictable winter weather?
The horses and cows grow long, thick, shaggy winter hair when it starts to cool down in the fall. This hair growth doesn’t actually have anything to do with temperature, though. It has to do with how many hours of sunlight there are each day, known as a photoperiod. As the photoperiod shortens, the horses and cows start growing their hair to get ready for cooler temperatures.
Horses and cows use this thick winter fur to trap a layer of air against their skin, which is slowly warmed by their body heat. The hair also scatters light, which may help insulate the animals. As long as they have shelter from north winds, they are comfortable outside, and they enjoy sunning themselves whenever possible.
We cut the wool off our sheep (a process called shearing) at the start of each summer. They spend the whole summer and fall growing new wool, instead of waiting for days to get shorter like the horses and cows. By the time they need it in the winter, they have their thick wool coats back to keep them warm until spring.
All of the animals also have to use more energy to keep warm, just like how shivering takes more work than standing still. They all have to eat more food to make up for the extra energy they spend staying warm.
Since the pigs don’t have a thick outer layer of fur, wool, or feathers like the other animals, they have to create a thick inner layer of fat to help insulate their bodies. To create this layer of fat, they have to eat even more food than the other animals.
The pigs also enjoy being given a few extra whole bales of straw, which they rip up and rearrange to create their own nests inside the hog house. They cuddle up tight against each other in these nests to share body heat. Pigs also enjoy sunning themselves, even on cold sunny days.