2 



University of California Publications. [Geology 



EICHNESS OF FAUNA. 



There is every evidence that the Quaternary fauna represent- 

 ing this group was very rich both in species and in individuals, 

 a condition doubtless due in large measure to an abundant food 

 supply. Climatic conditions probably were effective only through 

 their influence upon that potent factor. The abundance of food 

 is attested by the large number of mammalian remains found in 

 the asphalt, remains both of carnivores and herbivores, many of 

 which were of large size. There appears to be a more or less 

 intimate ecological relation between the large scavenging bird 

 and the large predatory mammal, in addition to the more obvious 

 relation between the latter and the large herbivore. The herbi- 

 vore, slain and partially devoured by the carnivore, becomes the 

 natural food of the large vulture ; its thick skin and its resisting 

 tissue rendering ineffective the efforts of the less powerful 

 scavengers. 



At present in this region the sole surviving vulture of gigantic 

 size is Gymnogyps calif ornianus. Before civilized man became a 

 disturbing influence, the deer, the panther and this condor 

 doubtless formed an important ecological group. The soundness 

 of this premise is attested by the difficulty with which early 

 California hunters kept the condors from carcasses hung up or 

 cached for food. With the advent of civilized man the large 

 native mammals such as deer, elk, antelope, and mountain sheep 

 as well as their natural enemy, the panther, began to decline 

 rapidly in numbers. Some in fact were practically swept into 

 extinction. The compensating influence of the introduced 

 domestic animals was insufficient to restore the original con- 

 dition because trap, gun and poison were directed at both 

 carnivore and scavenger. As a result in some measure of this 

 change the California condor is now one of our rarest birds. 



Whatever influences may have conspired in Pleistocene time 

 to carry the sloth, bison, horse, the saber-tooth and the lion from 

 the field were also effective in the extinction of most of the 

 scavengers so intimately dependent upon them. The gigantic 

 Teratornis and most of his somewhat smaller associates were 

 obliged to yield their places to forms that could subsist upon 



