Giant Beaver

Giant Beaver—This picture shows the giant beaver's skull and mandible compared to that of a modern American beaver. The difference in size is startling. (Richard Harrington)

Giant Beaver—The giant beaver was about the same size as a modern black bear. (Richard Harrington)

Giant Beaver—This picture shows the giant beaver's skull and mandible compared to that of a modern American beaver. The difference in size is startling. (Richard Harrington)

Giant Beaver—The giant beaver was about the same size as a modern black bear. (Richard Harrington)

Scientific name: Castoroides ohioensis Scientific classification: Phylum: Chordata Class: Mammalia Order: Rodentia Family: Castoridae

When did it become extinct? The giant beaver is thought to have become extinct around 10,000 years ago.

Where did it live? This giant rodent lived in North America. Its remains have been found from Florida to the Yukon and from New York State to Nebraska.

Modern-day beavers are big by rodent standards, with a weight of up to 35 kg for the European species (Castor fiber). Imagine, then, a prehistoric beaver that weighed around 200 kg and was around 2.5 m long—about the same size as a black bear (Ursus americanus). This was the giant beaver, and it was one of the largest rodents that has ever lived. Unlike extinct beasts, such as the mammoth and cave bear, the giant beaver has never been found depicted in cave paintings, so we can only make assumptions of its appearance in life based on its bones. In general appearance, the giant beaver was very similar to the modern-day species, just a lot bigger. Like the living beaver, this giant had its eyes high on its head so that it could see above the water when the rest of its body was submerged. The front incisors of the giant beaver were massive (about 15 cm long), relatively much larger than the incisors used by the living American beaver to gnaw through young trees. Unlike modern beavers, the front edge of the giant beaver's incisors was not smooth; instead, it was heavily ridged, and it has been proposed that these structures strengthened the very long teeth, protecting them from breakage when they were being used.

How did the giant beaver use these impressive teeth? Some experts believe that the teeth were for gnawing at wood, while others think that gouging was more likely. The giant beaver must have done some tree gnawing because if its modern-day relatives are anything to go by, nibbling wood is one way of keeping the ever-growing incisors in check. Like its surviving relatives, the giant beaver probably got some of its sustenance from eating bark to supplement the nutrients it obtained from eating aquatic vegetation.

The modern-day beavers love water and spend a lot of their time in lakes and rivers, but they are also very mobile on land and often travel good distances on foot from one lake to another. It has been suggested that due to its great size, the giant beaver may have been slow and clumsy on land; therefore it may have been predominantly an aquatic animal, only leaving the water to search for food. With that said, the immense bulk of the hippopotamus (Hippopotamus amphibius) does not stop it leaving the water to graze at night.

Where exactly did the giant beaver live? Many giant beaver bones have been found in old swamp deposits, so we can assume that this giant rodent preferred lakes surrounded by swamp, and it seems to have flourished in an area around the Great Lakes. Three almost complete skeletons have been found in Indiana and Minnesota. Toward the end of the last ice age, this region was dotted with numerous swamps and lakes—the probable preferred habitat of this giant rodent. The density of lakes, marshlands, rivers, and streams probably lent itself to the dispersal of an animal that was not fond of leaving the water. Giant beaver remains have been found over a very large area, so they were obviously occupying an ecosystem rich in aquatic habitats. Even if the giant beavers rarely moved far over land, they could have dispersed over great distances by traveling between the extensive network of interconnected lakes that once studded North America, the remnants of which we still see today.

The living beavers are unique for their building abilities. They construct lodges of saplings, branches, and twigs to live in and dams that curb the flow of rivers and streams.

These industrious efforts can change whole habitats. Did the giant beaver do the same, constructing enormous structures of saplings and cut wood? We have no way of knowing for sure, but in 1912, part of a young giant beaver's skull and its possible lodge were discovered near New Knoxville in Ohio. The lodge was said to have been 1.2 m high and 2.4 m across and was built from saplings with a diameter of 7.5 cm.

Like many of the other great beasts that once roamed North America, the giant beaver became extinct around 10,000 years ago. The exact cause of its demise is a mystery. As a species, the giant beaver survived for around 2 million years, and in that time, glaciers expanded and retracted as the earth's climate oscillated between longer cold and shorter warm periods for at least 10 cycles. The giant beaver survived all of these oscillations and the changes they brought, except the last one. Humans have been implicated in the extinction of the North American megafauna as there is thought to be a link between the spread of the prehistoric human population and the disappearance of the American continent's giant beasts, but there is no direct evidence that humans hunted the giant beaver. With that said, a 200-kg animal with lots of meat on its bones and a dense pelt that could have been made into warm clothing must have been coveted by prehistoric North Americans.

♦ The first remains of this animal were found near Nashport, Ohio, in a peat bog, and they were described as belonging to a giant beaver in 1838.

♦ The giant beaver lived alongside the modern-day American beaver (Castor canadensis). For two similar species to coexist, there must have been differences in the habitats they preferred or possibly in the food on which they depended. Perhaps the giant beaver, with its capacious mouth, was able to use larger trees for food and building, while its small relative could nibble away at smaller saplings.

♦ Even though North America still has its fair share of wilderness, it's hard to imagine what it must have looked like thousands of years ago, long before the advent of intensive agricultural and urban development. For millions of years, it was one vast wilderness completely untouched by humans, where the forests, plains, lakes, rivers, and swamps echoed to the calls of huge, long-dead animals. Indeed, the continents of North and South America were the last to be populated by humans and were the last to lose their diverse megafauna.

Further Reading: Harington, C. R. "Animal Life in the Ice Age." Canadian Geographical Journal 88 (1974): 38-43.

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  • BERENICE
    When was the giant beaver become exstincked?
    8 years ago
  • Edmondo
    How did the giant beaver become extinct?
    8 years ago
  • randy
    What are the relatives of a beaver?
    8 years ago
  • abbey
    Did a beaver used to be as big as a bear?
    8 years ago
  • Louie
    When did the beaver almost become extinct in minnesota?
    8 years ago
  • Isumbras
    What year did the beaver almost become extinct?
    8 years ago
  • HADDAS
    Did giant beavers live in indiana?
    8 years ago
  • kaycee
    How did the giant beaver become extinct animal?
    8 years ago
  • Eva Kelly
    Where did the giant beaver live?
    8 years ago
  • Eduardo
    Why did giant beavers become extinct?
    2 years ago
  • anna-liisa takkula
    Did giant beavers exist?
    1 year ago
  • Paula
    How did beavers come to north america?
    11 months ago
  • natale
    What animals were in the same area as giant beaver?
    8 days ago

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