In North America there exists a very curious species of Rodents, belonging to the sub-genus _Spermophilus_, or _Spermatophilus_--that is, "grain-eaters." They are better known by the hunter's name, "Prairie Dogs." Mr. Murray remarks that it is difficult to say _why_ they obtained such an absurd appellation, for they do not bear the slightest resemblance to the canine species, either in formation or habits.[139] "In size," he says, "they vary extremely, but in general they are not larger than a squirrel, and not unlike one in appearance, except that they want his bushy tail; the head is also somewhat rounder. They burrow under the light soil, and throw it up round the entrance to their dwelling like the English rabbit; on this little mound they generally sit, chirping and chattering to one another, like two neighbour gossips in a village. Their number is incredible, and their cities (for they deserve no less a name) full of activity and bustle. I do not know what their occupations are; but I have seen them constantly running from one hole to another, although they do not ever pay any distant visits. They seem on the approach of danger always to retire to their own homes; but their great delight apparently consists in braving it, with the usual insolence of cowardice when secure from punishment; for, as you approach, they wag their little tails, elevate their heads, and chatter at you like a monkey, louder and louder the nearer you come; but no sooner is the hand raised to any missile, whether gun, arrow, stick, or stone, than they pop into the hole with a rapidity only equalled by that sudden disappearance of Punch, with which, when a child, I have been so much delighted in the streets and squares of London." Captain Murray observes that as there is generally neither rain nor dew on the plains which they inhabit, during the summer, while, on the other hand, these little creatures never wander far from their "towns," it seems reasonable to conclude they need no other liquid than they can extract from the grass they eat. It is certain that they pass the winter in a complete state of lethargy and torpor, for they accumulate no supply of provisions against that season; while the herbage which thrives about their habitat dries up in autumn, and soon afterwards the frosts render it impossible for them to procure their ordinary food. When the prairie dog feels the approach of his time of somnolence--generally about the end of October--he closes all the passages of his dormitory to protect him from the cold, and wholly resigns himself to the pleasures of repose. He remains thus immured and inert until awakened by the first warm airs of spring, when he throws wide his gates and reappears on the surface of the refreshened earth, in all his whilome liveliness and gaiety. CHAPTER XI. ANIMAL LIFE IN THE PRAIRIES OF THE NEW WORLD:--BIRDS AND REPTILES.