ANIMAL TRACKS, FOOD AND DISPOSITION. 

 IS THERE ANY RELATION? 



E. L. PALMER 



"He that runs may read" but he that runs may also be read and 

 the reading of the tracks of birds and animals may lead to some 

 very interesting observations. When speeding all animals move es- 

 sentially alike so the following conclusions are based upon the 

 method of locomotion adopted by the animal w^hen moving slowly. 

 This is shown in the first line of tracks under those given for each 

 species. 



A study of the tracks shown in the plate will make it plain that 

 there are apparently three types based upon the behavior of the 

 limbs, — particularly the hind limbs. The rabbit, squirrel and deer- 

 mouse all move the hind limbs in unison while the front may or may 

 not work together. In these animals the hind limbs are also planti- 

 grade. The cat and the shrew move the hind limbs alternately as 

 they do also their fore limbs. When speeding, however, their hind 

 limbs are moved simultaneously. The cat at least is digitigrade. 

 The rat and the muskrat vary from each of these types. In these 

 animals, the hind limbs may or may not be moved in unison and 

 there is apparently no attempt to follow any definite plan of behavior 

 for the- fore limbs. This probably accounts in part for the peculiar 

 irregularly rolling gait w'hich these animals show. 



Possibly the above classification might not be of interest but when 

 we consider the food habits of each of these animals we find that 

 they readily classify themselves into the same groups. The rabbit, 

 squirrel and deer-mouse are essentially plant eaters. The cat and 

 shrew are out and out carnivors while the muskrat and rat are plainly 

 omnivorous. In connection with the food habits it would appear 

 logical to expect different methods of locomotion. Carnivors are 

 called upon to use caution in approaching their prey while this would 

 be unnecessary on the part of herbivors. Sudden movements such 

 as would arise from using the hind limbs simultaneously would jeo- 

 pardize their chances of securing their prey by surprise. Herbivors 

 do not need to exercise caution in securing a meal but do need to 

 be able to move rapidly in escaping from an enemy. It would seem 

 natural then to expect that movements on their part might readily 



