vibration. There were from four to six of these periods of vibration in a series. The tip of the tail would travel only a short distance, less than a couple of inches, as it was never seen to reach a vertical position above the animal's back when the squirrel was standing on all fours.
These squirrels are notably cautious about coming out of their holes; they were never seen to come out hastily. First the nose and then the eye of an animal would stealthily appear, and then a thorough look around for possible danger taken, before a squirrel considered it safe to leave the shelter of its burrow. However, when they do move, their actions are very sudden, as though they had been undecided just what to do, but having once made up their minds are off in a whirl of dust. These rodents are more easily alarmed by sound than by sight. The
Fig. 28. Young Nelson Antelope Ground Squirrel, photographed by J. Dixon, May 9, 1918, on lower San Emigdio Creek, Kern County. Note how well the general color of the animal blends with the tone of the background, and yet how strikingly the white of the under side of the tail shines forth.
cracking of a twig would send them hot-footed to their burrows. Yet the observer was able to walk up to within thirty feet of them in plain sight in the open as long as he made no violent motions. By approaching slowly and directly towards the squirrels, it was frequently possible to get within ten feet when they were sunning themselves at the entrances to the burrows under the overhanging banks.
The sense of smell seems to be extensively used in the daily life of these animals. At the close approach of the observer the noses of these little squirrels were seen to twitch constantly as if in effort to catch the scent of the stranger. The sense of smell also plays an important part in locating food. Then again it is used socially. When following each other about, in and out of the burrows, they often stop and sniff to see
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