I saw my very first groundhog in Massachusetts last week. It had just emerged from its winter home in the earth. I wanted to know more about the little fellow, so I did some research. Here are 12 things I found out about groundhogs:

1. They’re also called woodchucks and whistlepigs.
2. They’re a kind of rodent.
3. They like alfalfa and will grow up to 80 centimeters (32 inches) long, weighing up to 14 kilograms (30 pounds) if they can get lots of it.
4. They have two coats of fur – a grey undercoat and a second coat of “guard hairs” that give them their frosted appearance.
5. They have very dense cerebral bones that allow them to survive direct blows to the head that would kill other animals.
6. They usually live for two to three years, but can survive for up to ten years in captivity.
7. They will move around 320 kilograms (700 pounds) of dirt to dig a burrow that might be up to 14 meters (45 feet) long, 1.5 meters (5 feet) underground.
8. Their burrows are capable of creating sinkholes that imperil farm machinery and can even undermine building foundations.
9. They are one of the few species that enters a true hibernation period over the winter months, usually from October to March or April.
10. They can swim and climb trees.
11. Seeing as they prefer open, cleared country, their North American population is probably higher now than it was when European settlers first arrived.
12. They are very alert when not actively feeding, often standing upright and motionless, watching for danger.