UNDERWATER WINTER: Beavers

We’re listening to the sounds of beaver cubs. Beaver are a semi-aquatic mammal that have come up with some resourceful ways of surviving a long, cold winter. I’m Jim Metzner, and this is the Pulse of the Planet, presented by the American Museum of Natural History.

“Beaver enjoy the advantage of being able to modify their own environment to their liking, and they do this primarily through the construction of dams.”

Biologist Peter Marchand:

“By damming a stream, beaver are able of course to raise the water level to the point, then, where they can construct a lodge with a safe underwater entrance. Now, this entrance then remains usable throughout the winter because it is below water and below the level of the ice.”

And that means that beaver are able to come and go as they please all winter, without fear of predators, who can’t penetrate the lodge from the outside, nor gain access to the underwater tunnel. But once the pond freezes over, the beaver won’t be able to get to their favorite food, the inner bark of trees and shrubs. So, in the fall and early winter, they’ll turn the cold waters of the pond into a refrigerator, and they’ll cache their food in it.

“And caching food consists of nothing more than harvesting small trees and shrubs during the fall of the year, dragging them into the water and then literally planting the cut ends of the branches into the mud at the bottom of the pond. What this means, then, is that when the pond freezes over, the beaver enjoy the warmth of their lodge, and occasionally, then, leave the lodge, plunge into the water, make a quick foray to the food cache and then return to the lodge.”

We’ll hear more in future programs. Pulse of the Planet is presented by the American Museum of Natural History. I’m Jim Metzner.


Peter J. Marchand is the author of Life in the Cold, 3rd edition, published in 1996 by University Press of New England, Hanover, NH. ISBN 0-87451-785-0

UNDERWATER WINTER: Beavers

Beavers are animals whose resourcefulness helps them to make it through the winter.
Air Date:01/22/1998
Scientist:
Transcript:

We're listening to the sounds of beaver cubs. Beaver are a semi-aquatic mammal that have come up with some resourceful ways of surviving a long, cold winter. I'm Jim Metzner, and this is the Pulse of the Planet, presented by the American Museum of Natural History.

"Beaver enjoy the advantage of being able to modify their own environment to their liking, and they do this primarily through the construction of dams."

Biologist Peter Marchand:

"By damming a stream, beaver are able of course to raise the water level to the point, then, where they can construct a lodge with a safe underwater entrance. Now, this entrance then remains usable throughout the winter because it is below water and below the level of the ice."

And that means that beaver are able to come and go as they please all winter, without fear of predators, who can't penetrate the lodge from the outside, nor gain access to the underwater tunnel. But once the pond freezes over, the beaver won't be able to get to their favorite food, the inner bark of trees and shrubs. So, in the fall and early winter, they'll turn the cold waters of the pond into a refrigerator, and they'll cache their food in it.

"And caching food consists of nothing more than harvesting small trees and shrubs during the fall of the year, dragging them into the water and then literally planting the cut ends of the branches into the mud at the bottom of the pond. What this means, then, is that when the pond freezes over, the beaver enjoy the warmth of their lodge, and occasionally, then, leave the lodge, plunge into the water, make a quick foray to the food cache and then return to the lodge."

We'll hear more in future programs. Pulse of the Planet is presented by the American Museum of Natural History. I'm Jim Metzner.


Peter J. Marchand is the author of Life in the Cold, 3rd edition, published in 1996 by University Press of New England, Hanover, NH. ISBN 0-87451-785-0