[Fbone]

Originally Posted by SneakySnake

Beaver dams?

Yeah!

The largest structure built by an animal is that of a beaver's lodge and dam. Beavers (Castor canadensis) of North America use mud, wood, vegetation and stones to dam up water to form a pond and then build a lodge for winter refuge. The largest lodge ever recorded was 12.1 m (40 ft) across and 4.8 m (16 ft) high and the longest beaver dam ever recorded measured 1.5 km (0.9 miles) long.

Lodges typically measure 3-4 m (9 ft 10 in -13 ft) across, 3 m (9 ft 10 in) high, and take 20 days to build using 3 tons (6,613 lb) of materials. On average, a family of 4 beavers can build 1.5 m (4 ft 11 in) of dam wall per day. The design of the dam usually reflects the rate of the water flow, i.e the faster the water flows, the more curved the dam will be.