Which rodent is good at building dams?

Explanation

The beaver is a large rodent. It eats birch, sedges, pondweed, and water lilies, amongst other things. It is known for being very good at building dams, but it also digs canals so it can lodge wood down the water. This is much more work than the dams. A beaver can weigh around 40 kilo and reach 25-30 years, though normally they only live to be 15 years or so. The beaver is the national animal of Canada.