Though many humans are really into fitness, marmots are really into fatness.
Marmots are animals that look like this:
Though I don’t know how often they look like they are posing for a Glamour Shot.
The marmots of North America are found out west. One of their favorite habitats is mountain meadows, which are places that look like the bottom half of this:
Marmots like mountain meadows because they eat plants, mainly grass, flowers and seeds. They can only do this for about four months out of the year, though, because for the other eight months, mountain meadows tend to look like the bottom half of this:
Snow may cover everything on the mountains in the western United States from September until May. Though some mountain animals deal with the lack of food in the winter by migrating to warmer places, you are not ever going to look overhead and see a flock of marmots flying south for the winter. Marmots are pretty much stuck on the mountain where they live. Since marmots can’t leave, they have another strategy to survive the winter. They get really, really fat.
Fat is not just something that makes adults watch fitness videos. Fat is a way that animals, including people, store energy.
Like all living things, animals need energy to live. You, for example, are using energy right now, even if you sitting as still as humanly possible. As you sit as still as humanly possible, your body is using energy to breathe, to pump blood, to see, to hear, to keep your body temperature at 98.6 degrees Fahrenheit, and even to think to yourself, “How long am I going to sit here and do this?”
All animals get their energy from food. When a marmot eats a bunch of flowers, there is energy in the flowers. The marmots’ body will use this energy to power them through the day as they breathe, chew, drink water, scurry around, and pose on rocks for Glamour Shots. If a marmot eats more flower energy than it needs that day, then that extra energy gets turned into fat. The fat stores the energy so it can be used if needed on a later day (fat is basically like flabby batteries for animals).
Each marmot’s goal is to eat more energy then they use each day so they can be as fat as marmotly possible by the end of the summer. Being a big, fat marmot in September allows marmots to survive the winter when there's no food. Marmots can live off the energy stored in their fat.
Marmots do not have enough stored energy to be particularly active in the winter, though. You’re not going to see marmots skiing down the mountain or making snowmarmots. You’re probably not even going to see any of them awake. The fat can only keep marmots alive if they hibernate all winter.
Hibernating is kind of like sleeping through the winter, except it's different. When marmots, or any other animal hibernates, their inner body temperature cools down and their heartbeat, breathing and everything else happening inside their body slows down. By doing this, they need less energy to survive. If marmots just slept all winter, with normal heartbeats and body temperature, they would not have enough energy to survive.
Marmots hibernate in holes in the ground, often with their entire family joining them. Scientists think marmots hibernate in groups to help them stay warm so they use up less energy (basically, a marmot’s hibernating family members act like big, fat blankets). As marmots hibernate, they keep getting thinner and thinner as they burn off their fat energy. They stop hibernating when it warms up and the plants start growing and there is food available again. By the time marmots wake-up, they are superskinny, which makes them look more like a sausage than a ham.
Marmots then eat as much as they can all summer long. Some of them may need to double their body weight over the summer to have enough energy in their fat to survive the next winter.
So, yes, fat is an adaptation that helps animals survive, except, at this point in time, humans and their overfed pets. Someday, I may write about why, in the 21st Century, we're the exceptions.
To learn more about marmots, read my book A Day on the Mountain.
Online References and Resources:
The Alpine Marmot Foundation. "Hibernation."
Animal Diversity Web. "Marmota flaviventris: yellow-bellied marmot."
BBC Animals. "Cute marmots waking up from hibernation" video.
Encyclopedia of Life. "Marmota flaviventris: yellow-bellied marmot."
UCLA. "What's the life of a marmot like?"
Photos and Images:
Click the photos and images used above to find their sources.