In the great prairie-lands which lie to the east of the Rocky Mountains, this quaint little animal is exceedingly plentiful. It lives in underground burrows, and the earth which it digs out in making them is always piled up just outside the entrance in the form of a mound about two feet high, on the top of which it likes to sit upright, squatting on its hind quarters as a dog does when "begging." At the slightest alarm it utters its queer little yelping cry, throws a sort of half-somersault, and dives into its burrow, to reappear a few minutes later when it thinks the danger has passed away. A large number of prairie-dogs always live together, like rabbits in a warren, and sometimes the prairie, as far as one can see, is dotted all over with their mounds. Usually the animals are steadily moving eastward. They increase as ranching and farming spread over the plains; for the cultivation of hay and grain and the destruction of their natural enemies favor them. In parts of Texas and northward they are so destructive that united means of destroying them by poison have been adopted. It was formerly thought that prairie-dogs took in lodgers, so to speak, for small owls, known as burrowing owls, are often found in their tunnels, together with rattlesnakes; and it was supposed that all three lived peaceably together. But now we know that this is not the case, for the owls are nearly always found in deserted burrows, while the rattlesnakes undoubtedly enter the homes of the prairie-dogs for the purpose of feeding upon their young. MARMOTS Not unlike a rather big prairie-dog is the common marmot, which is found in considerable numbers in the mountainous parts of Northern Europe and America. Here it is named whistler or siffleur. More familiarly known is the American woodchuck, or groundhog, which burrows deeply in the fields of almost every farm in the country. These marmots are famous for their winter sleep. During the summer months they are very active and busy. From about the middle of autumn till the beginning of spring, however, they are fast asleep in their burrows, not waking up at all for at least six months! Before entering upon this long slumber they pack their sleeping-chamber full of dry grass, and in these warm beds survive the winter by the slow absorption of their fat, so that when they come out they are very lean. Another kind of marmot, called the bobac, is found both in Northern Europe and in Asia. It is sometimes eaten as food, but is most difficult to kill, for unless it is actually shot dead as it sits it will nearly always contrive to get back into its burrow. And if the animals are startled by the report of a gun they all disappear underground, and will not be seen again for several hours. BEAVERS