The snowbirds are now comfortably settled in their warm southern homes, and the migratory birds have set up their new homes, too. Temperatures are dropping below the zero mark as we hunker down and bundle up. You may wonder what has become of the outdoor animals that stay here in the frigid north…just before you take a big sip of whipped cream-covered hot cocoa. Mammals put on a thicker coat for the cold winter months and some of their fur even changes color for predator protection–the snowshoe hare and two species of weasel can be found in our region; the arctic fox is probably the most well known but not found in Michigan. Other mammals also “settle down for a long winters nap,” conserving energy and avoiding the need to look for food in four feet of snow.
So, without a fire place, flannel jammies, and a down-filled comforter what is a fish to do? Did you forget about the underwater creatures that not only have no way of leaving, but their homes become covered in inches-thick ice? Do they hibernate…do they lay eggs and die, like insects…large, old fish wouldn’t be possible then, so they must have a special way of making it through.
Even with a thick sheet of ice on top, water temperatures don’t drop below freezing and the warmest water is now at the bottom of a lake. Living in an environment that generally stays around 40 degrees doesn’t sound great, but we are weak from technological advancements and our warmblooded-ness. The fish species living in Northern Michigan waters are tough and adept to the temperatures, decreasing oxygen, and lack of food. It just sounds worse and worse, I know. As the ice thickens (blocking out more sunlight) throughout the winter, the amount of oxygen in the water decreases. Now, fish are poikilotherms, aka coldblooded and can modify their metabolism to the environment–meaning in the winter it can take almost a week for their food to digest. This would be beneficial for us as we eat our heavier “comfort” foods in the winter months. The slower they move, the more energy they conserve, the less they need to eat, and less oxygen is required.
Who could live like this?
Maybe you are an avid angler and this is old news. Maybe you will impress your friends with your new knowledge this weekend at a New Year’s Eve party with a little which-winter-fish-are-you? game. Laugh all you want, but as fish symbolize transformation, abundance, wisdom, happiness, and unity (in several different cultures) they are the perfect topic to ring in a new year. Cheers.