Spring is a time when flowers bloom and trees begin to grow. The days grow longer and the temperatures rise above 40 degrees. For the people who have weathered the winter, the melting of ice and thawing of the ground is greatly anticipated. During this period, creatures who have adapted to the freezing temperatures through miraculous transformations in bodily functions, now rise to an altered green landscape.
Many people have not witnessed these seasonal transformations, but as mountain dwellers in close proximity to these creatures, a glimpse becomes possible. Making it to spring is no small feat for animals that hibernate. To humans, hibernation may appear restful but for the animals who hibernate, this state can be arduous. Some of these animals expend huge bursts of energy so their body temperatures don’t dip too low and do it with little to no food and water.
Black bears will begin to emerge from their dens around April, but may stay lethargic for weeks. During this so-called walking hibernation, they sleep plenty and don’t roam very far. Despite losing up to one-third of their body weight over winter, they don’t have a huge appetite right away as their metabolism is not yet back to normal. They snack mostly on pussy willows and bunches of snow fleas. Slowly, the bears’ metabolism gears up to normal, active levels when plants start to sprout on the forest floor.
Bats have babies on their minds and fertilization happens a few days after females emerge from hibernation. After emerging from their Winter caves, the mothers-to-be move to a large tree or another cave. They are searching for a warm, stable environment where they can give birth to their young. Bats often return to the same maternity spot year after year sometimes traveling hundreds of miles to get there. Dozens of mothers will congregate and cuddle to keep warm. When their pups are born, 50 to 60 days later, mothers may help each other by taking turns foraging for insects and roosting with the group. With no parenting responsibilities, and perhaps to avoid competing with the females, males will stay in torpor for longer.
Bumble bees are lone hibernators. When the temperature drops, males and worker bees die off but the queen survives by hibernating. She hibernates in a hole in the soil, in rotten tree stumps or under leaf litter. She will emerge 6-8 months later, warm-up and then find a nice spot to build a nest and create a whole new team of bees.
Unlike the bumblebee, who hibernates alone, garter snakes hibernate in groups. In the mountains where winters are exceptionally cold, there can be hundreds and sometimes thousands of snakes grouped together for warmth. Once spring arrives and the snow melts, they head out of their winter homes to bask in the sun. It’s a unique site to see.
Each year late in the fall, the wood frog does a very strange thing: They freeze almost solid. Two-thirds of their body water turns to ice. If you picked them up, they would not move. If you bent one of their legs, it would break. Inside these frozen frogs other weird and amazing things are going on. Their hearts stop beating, their blood no longer flows and their glucose levels sky rocket. The craziest thing of all may be that they can withstand temperatures as low as zero degrees Fahrenheit for as long as seven months. When spring comes and the frogs thaw, they turn as much of the glucose as they can back into glycogen, and they pee out the rest and hop away. They hurry to the nearest pond or lake to start mating. They are very adamant about getting busy as they only have about five months to make babies and gather all the food that they can before the freezing process starts again.
These animals, among several others, are going through a constant process of change in order to adapt to the World outside. Seen or unseen, humans are not alone when it comes to winter preparation. Outside our door’s creatures are following suit in their own unique ways.