26 ILLINOIS NATURAL HISTORY SURVEY MANUAL 4 



7. Each set of 4 footprints with a pair tandem and a pair side 



by side or almost side by side, fig. 16 rabbit^ 



Each set of 4 footprints usually arranged otherwise 8 



8. Claw marks absent or continuous with the marks made by 



the toepads, figs. 18, 21 9 



Claw marks usually apparent and separate from marks 

 made by the toepads, figs. 24, 29 10 



9. Print of hind foot with 4 toe marks, figs. 18, 25 



weasels, mink, cats 



Print of hind foot with 5 toe marks, figs. 20-23 



raccoon, muskrat, rats, river otter 



10. Print of hind foot with 4 toe marks, figs. 24, 26, 27 



dog, coyote, foxes 



Print of hind foot with 5 toe marks 11 



11. Footprints showing webbing between toes, fig. 28 beaver 



Footprints not showing webbing, fig. 29 12 



12. Prints of front and hind feet rounded, figs. 29-33 



woodchuck, mice, voles, shrews 



Print of hind foot elongate, figs. 20, 22 13 



13. Rounded print of front foot with 4 toe marks, figs. 22, 34 



squirrels, rats, mice 



Rounded print of front foot with 5 toe marks, figs. 20, 3 5. 36 - 

 raccoon, skunk, badger 



Preserving Tracks. — Tracks can be preserved for study in 

 four ways. The simplest way is to photograph imprints in snow 

 or mud and make a collection of pictures of the different types. 

 A second way is to sketch the imprints and keep the sketches in 

 a notebook or card file. A third way, which is interesting but 

 somewhat more laborious, is to make plaster facsimiles. This 

 may be done by pouring plaster of Paris mixed with water into 

 and around the tracks and allowing it to harden; then remov- 

 ing the plaster cast, brushing it clean, greasing it, and pressing 

 it into a plate of freshly mixed plaster, thus duplicating the 

 original impressions. A fourth way, similar to the third, can be 

 used for tracks in mud by letting tallow from a burning candle 

 drip into the imprints. When the tallow solidifies, it can be 

 lifted up, cleaned, and stored, or used to make a plaster cast. 



Scats or Droppings.— The study of scats or droppings (sca- 

 tology) is often helpful in providing clues to the identity of the 

 mammals frequenting an area and also in determining the food 

 habits of these mammals. As in the case of tracks, some scats 

 are easily recognized, others have characteristics which seem to 

 defy adequate description but can be learned by observation, and 

 some cannot be identified with certainty even by experts. 



