Chapter X 



PAPIO CYNOCEPHALUS, THE COMMON DOG-HEADED BABOON, 

 ITS BRAIN AND BEHAVIOR 



Its Position among the Primates; Measurements and Brain Indices; Surface 

 Appearance of the Brain; Internal Structure of the Brain Stem in Cross Section 



T 



"^HE genus Papio comprises all of the cynocephalous or dog-headed 

 baboons. In general, these animals possess a massive body, and the 

 adult is remarkable for its great strength. As a group they are con- 

 sidered the lowest of the old-world or Catarrhine monkej^s. Because of their 

 large size and great strength they are looked upon as dangerous animals 

 particularly as they have aggressive, ugly natures. 



Appearance of the Baboon 



The face and head of the baboon are dog-hke and elongated ; the nostrils 

 have a canine disposition. The tail is variable in length but never prehensile 

 and sometimes only rudimentary. It is usually carried with a curve near the 

 basal extremity arching away from the body, the remainder of the tail hang- 

 ing straight downward. All species of papio possess callosities or fleshy pads 

 about the buttocks which in some instances are of large size and brilliantly 

 colored, the coloring being intensified especially in the females during the 

 mating season. At such times these callosities in the females may increase in 

 size so that they cover nearly the entire gluteal region. Along the rostrum 

 of certain species there develop bony ridges elevated nearly to the level of the 

 eyes. These ridges are most common in the males and the skin over them is 

 brightly colored. In the mandril the skin over the ridge is of a bluish color, 



while the skin on the bridge of the nose is red. This coloring adds considerably 



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