TRACKS IN THE SAND 69 



sence of claw marks. The pads show distinctly, 

 but the feline race keeps the claws concealed in 

 sheathes until they are needed for execution. 



After a rain, the sand may be so hard packed 

 that the tracks of lighter animals or birds do 

 not show or show only at intervals, so that their 

 interpretation becomes difficult. I have seen the 

 characteristic tracks of a skunk arranged in close 

 linear fashion as he ambled slowly along, or in 

 diagonal lines of fours, as he quickened his pace, 

 change to a single foot mark every two or three 

 feet where the sand was so hard that it only oc- 

 casionally showed an impression. Such a sand 

 surface is well pitted by the rain, a condition 

 shown in several photographs. 



On the beach sand, hard-packed by the waves, 

 this state of things is not uncommon and a fox 

 may trot along and leave no trace on the hard 

 surface until he springs away in haste. The 

 tracks of sanderlings are often invisible, but their 

 recent presence is plainly shown by the series of 

 curving lines of probings, which are sometimes 

 nearly continuous furrows. A flock of plovers 

 may leave nothing to mark their presence on the 



