THE BEAVER. 565 
Lemmings are on their pilgrimage. While they are crossing the rivers or lakes, the fish 
come in for their share of the banquet, and make great havoc among their columns. It is 
a very remarkable fact that the reindeer is often seen in chase of the Lemmings; and the 
Norwegians say that the deer is in the habit of eating them. This statement, however, 
seems to be rather of doubtful character. The termination of these extraordinary migrations 
is generally in the sea, where the survivors of the much-reduced ranks finally perish. 
Ma. Lloyd mentions that just before his visit to Wermeland, the Lemming had overrun 
the whole country. The primary cause of these strange migrations is generally thought 
to be hunger. It is fortunate for the country that these razzias only occur at rare intervals, 
a space of some ten or fifteen years generally elapsing between them, as if to fill up the 
places of those which were drowned or otherwise killed in the preceding migration. 
The Lemming feeds upon various vegetable substances, such as grass, reeds, and 
lichens, being often forced to seek the last-named plant beneath the snow, and to make 
occasional air-shafts to the surface. Even when engaged in their ordinary pursuits, and 
not excited by the migratorial instinct, they are obstinately savage creatures. Mr. Metcalfe 
describes them as swarming in the forest, sitting two or three on every stump, and biting 
the dogs’ noses as they came to investigate the character of the irritable little animals. If 
they happened to be in a pathway, they would not turn aside to permit a passenger to 
move by them, but boldly disputed the right of way, and uttered defiance in little 
sharp, squeaking barks. 
The colour of the Lemming is dark brownish-black, mixed irregularly with a tawny 
hue upon the back, and fading into yellowish-white upon the abdomen. Its length is not 
quite six inches, the tail beimg only half an inch lone. 
THE common BEAVER has earned a world-wide reputation by the wonderful instinct 
which it displays, independently of its very great value in producing costly fur and 
perfume. 
This animal is found in the northern parts of Europe and Asia, but is found in the 
ereatest profusion in North America. In days long gone by, the Beaver was an inhabitant 
of our own island. It is generally supposed that there is but one species of true Beaver, 
and that the Beaver of Europe and Asia is specifically identical with that of America, 
even though certain small differences of fur and colourmg may be discerned between 
them. The social Beaver of Northern America is a truly wonderful animal, displaying 
a singular mixture of reason and instinct, together with a curious absence of both on 
occasions. The best account of this animal is to be found in Audubon and Bachman’s 
valuable work on the quadrupeds of North America, to which work I am indebted for the 
following particulars. 
The Beaver lives in societies, varying considerably in number, and united together in 
the formation of works which may fairly be considered as belonging to the profession of 
the engineer. They prefer to make their habitations by small clear rivers and creeks, or 
close to large springs, although they sometimes take up their abode on the banks of lakes. 
Lest they should not have a sufficient depth of water in all weathers and at all 
seasons, the Beavers are in the habit of building veritable dams, for the purpose of raising 
the water to the required level. These dams are composed of tree-branches, mud, and 
stones, and in order effectually to resist the action of the water, are about ten or twelve 
feet in thickness at the bottom, although they are only two feet or so wide at the summit. 
When the different parts of the stream run with varying velocity, the formation of the 
dam is really a triumph of engineering skill, for wherever the stream is gentle, the dam is 
built straight across it; but wherever the current runs smartly, the dam is curved so as 
to present a convex surface to its force. It often happens that when a dam has 
been made for some years, its dimensions become very large, in consequence of the 
trees and branches that are intercepted by it, and in process of time it sprouts thickly 
with vegetation, and even nurtures trees of some dimensions. 
In forming the dam, the Beaver does not thrust the ends of the stakes into the bed of 
the river, as is often supposed, but lays them down horizontally, and keeps them in their 
place by heaping stones and mud upon them, The logs of which the dam is composed 
