Prairie-dogs are not really dogs at all, but a kind of a squirrel called a marmot. As the visitors to city Zoological Parks already know, these animals make little mounds of earth, and a great many of these are found in one locality, which is known as a "dog-town." It is possible to travel for days at a time through country which is dotted over with mounds, every one of which is the home of a pair or more of prairie-dogs. These mounds are usually about eighteen feet apart, and consist of about as much earth as would fill a very large wheelbarrow. This is thrown up by the prairie-dog when he digs out his subterranean home. His dwelling sometimes has one entrance and sometimes two, and there are many much-traveled paths between the different hillocks, showing that they are very neighborly and sociable with one another.

In choosing a town site, they select one which is covered with short, coarse grass, such as is found especially in fields on high ground and mountain sides, for it is on this grass and certain roots that the prairie-dogs feed. On the plains of New Mexico, where for miles you will not find a drop of water unless you dig down into the earth for a hundred feet or so, with no rain for several months at a time, there are many very large "dog-towns," and it is, therefore, clear that they are able to live without drinking, obtaining enough moisture for their needs from a heavy fall of dew.

At about the end of October, when the grass dries up and the ground becomes frozen hard, so that digging is out of the question, the prairie-dog creeps into his burrow, blocking up the opening in order to keep out the cold and make everything snug, and goes to sleep until the following spring, without having had to lay up a store of food, as some animals do, to last him through the long, hard winter months. If he opens up his house again before the end of cold weather, the Indians say it is a sure sign that warmer days are near at hand.

If one approaches very cautiously so as not to be observed, a large "dog-town" presents a very curious sight. A happy, animated scene stretches away as far as the eye can see. Little prairie-dogs are found everywhere, on the top of their mounds, sitting up like squirrels, waving their tails from side to side and yelping to each other, until a most cheerful-sounding concert is produced. If you listen carefully, as you draw nearer, however, you will notice a different tone in the calls of the older and more experienced animals, and that is the warning signal for the whole population to disappear from view into their burrows. Then, if one hides quietly in the background and waits patiently for some time, sentinels will mount up to their posts of observation on top of the mounds and announce that it is safe to come out of their burrows and play about again, as the danger is past.