Woodchucks!

You might be familiar with this adorable mammal from seeing pictures of it on groundhog day. These groundhogs, or woodchucks, are field dwellers whose hibernation patterns influenced the rise of groundhog day.

 

Woodchucks' primary diet consists of grass. Since grass does not have great nutritional value, woodchucks must eat immense portions of it. They spend their whole summer and autumn gorging themselves, building up fat reserves for the winter hibernation. Their main foraging times are in the morning and afternoon. Forage sessions usually last no more than two hours.

 After the first frost, woodchucks retire to their burrows to sleep the winter away. During hibernation, their heart rate falls very low, and their body temperature is about that of their burrow. Their only means of staying alive is through their fat reserves. Thus, they must lower their heart rates to at most four beats per minute. The burrows they dig are five to thirty feet deep, which is why woodchucks are sometimes considered pests if they dig burrows in a person's front yard. The burrows are full of complex passages, chambers, and escape holes. In spring, woodchucks give birth to litters of of about six kits. They are solitary animals, meaning that their mates do not stay with them to tend the offspring.

When a woodchuck spots a predator such as a hawk,  fox, or raccoon, it will release a sharp whistle. This is a warning to other woodchucks so they can dash into their safe burrows.