12 POCKET GOPHERS OF THE UNITED STATES. 



but usually ran backward to the place of deposit, returning for more, 

 and repeating the operation again and again, the to-and-fro movement 

 suggesting a shuttle on its track. The well-known peculiarity of the 

 external genitalia, which are so hidden and modified that the sexes are 

 determined with difficulty, is doubtless the result of this habit, pro- 

 tecting the parts from injury when the animal is moving backward. 



In all Pocket Gophers the tail is rather large and fleshy, and as a 

 rule is naked or scantily haired. Its function had long been a puzzle, 

 but the Gopher above mentioned used it as an organ Of touch when 

 running backward. The tail is doubtless endowed with special sensi- 

 bility and is evidently of great value in warning the animals of the 

 presence of an enemy in the rear when they are traveling backward in 

 their dark tunnels. 



In walking on soft ground the forefeet are usually held in the normal 

 position, with the soles down, or inclined slightly inward. In walking 

 on hard ground, however, the forefeet are turned sideways, their soles 

 facing one another, so that the claws curve inward, and the animal 

 walks on the outer or ulnar side of the foot. This method of using the 

 forefoot in walking on hard substances was frequently observed, and 

 enables the animal to walk comfortably where the long curved claws 

 would be in the way if held in the normal positiou. It was also 

 frequently noticed that the feet were held in the same position (horizon- 

 tally) when at rest, and when used as a scoop in pushing loads of earth 

 or sand out of the way. When thus engaged the feet were drawn back 

 under the breast, the wrists near together and the long claws turned 

 outward. By moving the body quickly forward the animal always suc- 

 ceeded in throwing ahead of it a considerable quantity of loose earth. 



Burrows. — Gopher burrows seem to have neither beginning nor end. 

 They are extended and added to year after year, and in many cases 

 those dug by a single animal would measure a mile or more if straight- 

 ened out. I have never attempted to ascertain the actual length of 

 one, but feel secure in making the above statement. At the end of a 

 year a Gopher may often be found within 20 rods of the j>oint from 

 which he started, but in traveling this distance he has paid no atten- 

 tion to the points of the compass. He follows a tender root for a few 

 feet, then moves to one side, encounters a stone, and makes a second 

 turn. A layer of mellow soil entices him off in another direction, and 

 so on through a thousand devious crooks and turns. Sometimes the 

 main passage swings around and crosses itself, or numerous side 

 branches are extended varying distances. The main tunnel usually runs 

 from 6 inches to a foot below the surface. At intervals varying from 

 a few feet to a few rods openings are made through which to discharge 

 the earth that makes the little piles called ' gopher hills.' The open- 

 ings are closed by being packed so full of dirt that no trace of the. run- 

 way is visible except the little mounds that mark its course. An aver- 

 age-sized gopher hill contains 5 or 6 quarts of earth, but the quantity 



