SMALLER MAMMALS OF NORTH AMERICA 



397 



The young, in litters of from two to eight, 

 are born at irregular times according to the 

 latitude and general weather conditions. In 

 the south at least several litters appear to be 

 born each year, the young being noted almost 

 every month. 



When camping alone for a few days in the 

 desert near San Ignacio, in the middle of the 

 peninsula of Lower California, I had a unique 

 opportunity to learn something of the peculiari- 

 ties of the various pocket mice. Three species 

 were abundantly represented, including both 

 the silky and the spiny kinds. They quickly 

 learned that good hunting could be found in 

 and about the tents for the rice grains and 

 other scattered food and promptly took advan- 

 tage of it. 



As soon as approaching darkness began to 

 render objects indistinct, from their burrows 

 among the surrounding bushes they swarmed 

 into camp and were busy throughout the night 

 minutely searching the ground under the shel- 

 ter tent for every particle of food. In order 

 to see these interesting visitors to better advan- 

 tage I placed a candle on a small box in the 

 middle of the tent. 



Five or six individuals, representing three 

 species, often came within the circle of light at 

 the same time. At first all were shy and when 

 I made any sudden movement would leap in 

 every direction, like grasshoppers, and quickly 

 vanish. The smallest of the species, a member 

 of the silky group, was the shyest of all and 

 remained timid and reserved. 



The two larger species, representing both the 

 spiny and the silky groups, were much more 

 bold and quickly became confiding and delight- 

 fully friendly. Their attention was promptly 

 attracted to rolled oats which I scattered on 

 the ground in a spot well lighted by the candle. 



Sitting quietly close by the bait where the 

 visitors congregated I soon had evidence that 

 among themselves these little beasts are ex- 

 tremely pugnacious. The first to reach the 

 food would fiercely charge the next comer and 

 always try to leap upon its back, at the same 

 time delivering a vicious downward kick with 

 its strong hind feet. Occasionally the new- 

 comer would charge the one already at the 

 food. 



When five or six were trying to secure sole 

 possession of the small food pile there was 

 lively skirmishing about the premises, as they 

 alternately attacked and pursued one another 

 over the sand and among the boxes and other 

 camp gear scattered about. Amazingly quick 

 in movements, they would leap now forward, 

 now sidewise, now straight up a foot or more 

 in the air, with almost equal celerity ; and the 

 direction of their movements when attacked 

 was often unexpected. When running about 

 on the level sand they had a steady, swiftly 

 gliding motion, which their tracks showed was 

 the result of a series of little jumps. 



Both the spiny and the silky pocket mice be- 

 came so confiding the first night that when I 

 put my hand on the ground palm up with a 

 little rolled oats in it the nearest pocket mouse 

 would run to it, stop for an instant to smell 



the finger-tips, and then mount and sit quietly 

 on the palm and fill its cheek pouches. 



At such times the mice showed no uneasi- 

 ness, even when raised in my hand to within 

 a few inches of my eyes in order that I might 

 observe their movements more closely. The 

 motions of their front feet when putting food 

 into the pouches were so rapid that it was im- 

 possible to follow them. The nose was held 

 just over the food pile, and the cheek pouches 

 would slowly but visibly swell as they were 

 filled until they stood out like little bladders 

 on each sHe of the head. 



As soon as they were full the mice became 

 uneasy to get away and would run from one 

 side of my hand to the other peering down 

 the abysmal depth of three feet to the ground 

 without daring to leap. As soon as my hand 

 was lowered to the ground the mouse darted 

 away to carry the food to its store in the 

 bushes twenty to thirty yards away, quickly to 

 return with empty pouches. 



The mice soon became so tame that while 

 they were on my hand or on the ground I 

 could with one finger of the other hand stroke 

 gently the tops of their heads and backs and 

 even pick them up by their tails and suspend 

 them head down. When thus held they re- 

 mained motionless, their tiny front feet like 

 little closed hands held against their breasts. 

 When lowered and released they would imme- 

 diately resume the filling of their pouches as 

 though nothing had happened. Several indi- 

 viduals of the dozen or more which made free 

 of the tent had lost part of their tails, so that 

 they could be readily distinguished. 



One of these little bobtails was so gentle and 

 confiding that I became much attached to it. 

 It would permit all manner of familiar treat- 

 ment, such as being picked up by one foot or 

 by the tail, or being turned on its back. With 

 this confidence came a sense of proprietorship 

 in the good things here so suddenly and myste- 

 riously plentiful, as was shown by his attitude 

 toward his fellows. 



Again and again when he was filling his 

 pouches from a pile of rolled oats in my hand 

 I lowered it in a gently sloping position within 

 ten or fifteen inches of another mouse gather- 

 ing food on the ground. Thereupon the little 

 bobtail in my hand would invariably leave the 

 task of filling his pouches and without hesita- 

 tion leap down on the back of the one on the 

 ground. The surprised animal thus assailed 

 from an unexpected quarter always fled in 

 terror. 



After a short pursuit the bobtailed one would 

 come running back and instead of going to the 

 equally inviting pile of food on the ground 

 would come straight to my hand and complete 

 his task. The industry of the little animals 

 appeared to be tireless, as working swiftly they 

 made trip after trip with pouchloads of food 

 to their stores and quickly returned. One night 

 I watched this strenuous work for two hours 

 until I retired. 



The abundance and boldness of pocket mice 

 and kangaroo rats at this place led me to be- 

 lieve that there had been a former abundance 



