Cape Breton's Magazine

BEAVER CONTINUED PROM PAGB 15 female but actually helping in the care of the young. The female eats the after? birth • the only carnivorous act of this vegetarian creature.) Dave Algar; The beaver's a water animal and he's active all year round in the wa? ter. He has very thick layers of fat which keep him warm. The oil he puts over his fur waterproofs him, so his body core stays dry and warm.He has extremely large lungs for his size and he breathes more completely than we do, exchanging 807o of his air. We exchange only 20%. His liver is very large so he can handle large con? centrations of carbon dioxide and other poisonous compounds that build up when you're holding your breath. He can hold his breath 15 minutes. And he can exhale air and it'll get'trapped under the ice. Then he swims up and re-breathes it and stays under longer. And when he goes un? der water his heartbeat automatically slows down and the amount of blood circu? lating through the body is concentrated in the major organs, in the brain and in the heart • blood-flow to the extremeties is lessened and the inner part is kept warm and gets lots of oxygen. He has a transparent eyelid. Nostrils are on the side of the nose, well-suited for closing when swimming. The ear has a valve which closes automatically when he goes under. He has very fleshy lips • just like a muskrat • so he can work underwater with his teeth exposed but chips and water are not going down his throat. The front teeth continue growing, and they are continually The beaver was trapped to extinction throu; worn down as the beaver chews. The outside of the front part is much harder than the back part • so the back part wears down faster in a chisle shape. Grey Owl says he can slide his teeth sideways to put a little more edge on them. Should a tooth get broken, the others will continue to grow and handicap and eventually kill the beaVer. The paws have five digits and the front ones, used for digging, are very skillful. The hind feet are much larger • they're the ones used in swimming • but even there the nails are especially adapted. The nail on the second digit is split and the beaver uses that to comb the oil into his fur. Here in the park, the beaver are confined to a few prime areas which enable them to make it through the winter. The park does not have a lot of poplar trees accessible, and it doesn't have the wide variety of species the beaver needs to replace poplar. The park is managed is preserve it, which means we don't have logging and fires • the sort of disturbances that make for suitable ground for poplar to come in. The beaver have a slightly easier life in the lakes and ponds • there's roots of water plants in the bottom of lakes. Those that have their lodges in rivers and creeks have a much harder time and most don't make it through. When the two-year olds leave home they can't find a good location to sur? vive. So you're just left with those few colonies primarily in lakes and ponds. Now outside the park, where there are distur? bances, there are populations out there. ighout Cape Breton, and to near-extinction across North America • a remarkable feat in the light of ??.T.Seton's estimate million beaver in the territory of the U.S. when the v 'ite man arrived. Dr. A of 60- ory ot the U.S. when the White man arrived. Dr. Austin Cameron in his book MAMMALS OF THE ISLANDS IN IHE GULF OF ST. LAi''lRENCE writes; ??*Ac- cording to early reports the beaver originally was widely distributed throughout the island, but by 1869 it was absent from all of the province east of Itort Medway, Queen's County. Between 1937 and 1944 five introductions of beaver were made to the island. In 1937, four animals were released at North River, Victoria County; in 1938 nine were released near Ingonish in the Cape Breton Highlands National Park; in 1944 three were liberated at Tillard River, Richmond County; and two at Northwest Brook (River Ryan), Cape Breton County. Three further releases were made on the island in 1952. Although many of the streams on the island are fast-flowing and therefore un? suitable for beaver, the released animals have increased and spread out from the original sites. In the Ingonish area, the animals released in 1938 required several years to become established, but from 1941 onward a gradual increase was noted. Pop-' lar, the favourite food of this rodent, is uncommon in the Park area but is quite plentiful in river valleys in the central and southern parts of the island. In some cases the writer found that the beaver, rather than construct lodges and dams to live in, used bank burrows, because the violent fluctuations in the water-level of the fast-flowing streams on the island made them difficult to dam." r- • r Trapping records give us some idea of the size of Cape Breton's population, but Dan Banks, biologist with N.S. Dept. of Lands and Forests, points out that the number of beavers shown depends not only on the population but on numbers of trappers active, price of fur, length of season, etc. The peak year was 1971, when 409 beavers were taken in Cape Breton County alone. The total for the island taken in 1972-73; 539; in 1973-74; 601; and in 1974-75;461. That 461 breaks down into 225 for Cape Breton County; 126 for Inverness; 54 for Richmond; 56 for Victory County. Thanks to Dan Banks, Baddeck, and Gary Saunders, Kentville. Lands and Forests, and the Library, College ot Cape Breton, for their help; and to L.J.Boner. N.S.Communi? cations and Information Centre, for the beaver photo. SUGGESTED FURTHER READING; LaRue, THE 'ORLD OF THE BEAVER; Wilsson, MY BEAVER COLONY; Grey Owl, MEN OF THB LAST FRONTIER, PILGRIMS OF THE 'VILD and SA.TO AND THE BEAVER PEOPLE, as well as the Jan.- March. 1976. issue of NATURE CANADA. CAPE BRETON'S MAGAZINB/22