SKU: MtBvSk

Here we have a complete disarticulated skeleton of a Mountain Beaver that has been Beetle Cleaned and Whitened.

Mountain Beaver : Aplodontia rufa Mountain Beavers are brown in color, but fur can range from slightly more reddish or blackish depending on subspecies. There is a light patch under each ear. The animals have distinctively short tails. Adults weigh between about 500-900 g with a few specimens topping 1,000 g. Total length is about 30-50 cm with a tail length equal to 1-4 cm.

The skull is protrogomorphous. This means that it has no specialized attachments for the masseter muscles as seen in other rodents. It is flattened and lacks a postorbital process. The baculum is thin and distinctly forked. The penis is about 4.5 cm in length. They do not have a true scrotum, but testes move into a position called semiscrotal during the breeding season.

Mountain Beavers have an unusual projection on each molar and premolar which is unique among mammals and allows for easy identification of teeth. This projection points toward the cheek on the upper toothrow, but points toward the tongue on the lower. The cheek teeth lack the complex folds of other rodents and are instead comprised of a single basin. They are hypsodont and ever-growing. Two upper and one lower premolars are present. All three upper and lower molars are also present.

Mountain Beavers cannot produce concentrated urine. They are thought to be physiologically restricted to the temperate rain forest regions of the North American Pacific coast due to their inability to obtain sufficient water in more arid environments. Their karyotype is 2n=46.

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