At the root the horns are nearly three inches square, the flat sides opposite; they are marked with closely connected ridges and end in a tapering flat point.
When the horns grow to a great length, forming a complete curve, the tips project on both sides of the head so as to prevent the ram from feeding.

This, with their great weight, causes the sheep to dwindle to a mere skeleton and die.

The bighorn sheep feed much in the caverns of the Rocky Mountains, eating a kind of moss and grass growing on the floors of these caves, and also a peculiar soft, sweet-tasting "clay", of which the natives also are fond.
The southern part of British Columbia contains the mule deer of western North America (_Mazama macrotis_), and a very strange rodent, the sewellel or mountain beaver (_Haplodon_), a creature distantly allied to squirrels, marmots, and beavers, but restricted in its distribution to a few parts of California, Oregon, and British Columbia.

Amongst the birds noteworthy in the landscape are the white-headed sea eagles and Californian condors (_Pseudogryphus californianus_).

Humming-birds range through British Columbia and Vancouver Island between mid-April and October.
In the regions about the upper Kootenay River (Eastern British Columbia), before the railway was constructed, there were wild horses, descended, no doubt, from those which had escaped from the Spaniards in New Mexico and California.