32 LAND MAMMALS IN THE WESTERN HEMISPHERE 



The foregoing account refers to what may actually be 

 observed at the present time ; in regard to the Pleistocene, 

 Professor Merriam says: ''In the natural accumulation of 

 remains at the tar pools through accidental entangling of ani- 

 mals of all kinds, it is to be presumed that a relatively large 

 percentage of the individuals entombed would consist of young 

 animals with insufficient experience to keep them away from 

 the most dangerous places, or with insufficient strength to 

 extricate themselves. There would also be a relatively large 

 percentage of old, diseased, or maimed individuals that lacked 

 strength to escape when once entangled. In the census of 

 remains that have been obtained up to the present time the 

 percentages of quite young, diseased, maimed, and very old 

 individuals are certainly exceptionally large. ... In addi- 

 tion to the natural accumulation of animal remains through 

 the entangling of creatures of all kinds by accidental encoun- 

 tering of the tar, it is apparent from a study of the collections 

 obtained that some extraordinary influence must have brought 

 carnivorous animals of all kinds into contact with the asphalt 

 with relatively greater frequency than other kinds of animals. 

 In all the collections that have been examined the number 

 of carnivorous mammals and birds represented is much greater 

 than that of the other groups. . . . Whenever an animal of 

 any kind is caught in the tar, its struggles and cries naturally 

 attract the attention of carnivorous mammals and birds in 

 the immediate vicinity, and the trapped creature acts as a 

 most efficient lure to bring these predaceous animals into the 

 soft tar with it. It is not improbable that a single small bird 

 or mammal struggling in the tar might be the means of en- 

 trapping several carnivores, which in turn would naturally 

 serve to attract still others. ... In the first excavations 

 carried on by the University of California a bed of bones was 

 encountered in which the number of saber-tooth and wolf 

 skulls together averaged twenty per cubic yard." ^ 



1 Memoirs of the University of California, Vol. I, pp. 209-211. 



