NO. 5 MAMMALS OF PANAMA — GOLDMAN 225 



AOTUS ZONALIS Goldman 



Canal Zone Night Monkey 



[Plate 38, figs. 1 ia] 



Aotus sonalis Goldman, Smiths. Misc. Coll., Vol. 63, No. 5, p. 6, March 14, 

 1914. Type from Gatun, Canal Zone, Panama (altitude 100 feet). 



The night monkey of the Canal Zone and eastern Panama may be 

 easily recognized among the monkeys of the region by the characters 

 given for the genus. It is similar to Aotus griseimembra of the 

 Santa Marta region of Colombia in external appearance, the principal 

 difference being a more buffy suffusion of the body and limbs. The 

 skull differs in numerous details, especially the broader braincase, 

 and the more depressed interorbital region which materially alters 

 the facial angle ; the larger molarif orm teeth of the Panama animal 

 would alone serve as a distinguishing character. A species differing 

 in the reddish color of the feet, Aotus rufipes (Sclater), has been 

 described from Nicaragua. 



Owing to nocturnal habits the night monkeys are seldom seen, and 

 are therefore little known. Near Cana an example was obtained by 

 me while using a hunting lamp in the forest at night. Its large eyes 

 glowed conspicuously in the field of light projected into a tree top. 

 Rustling branches and low squeaking sounds indicated that others 

 were hurrying away in alarm. I did not hear the voice of the animal, 

 which was described to me by native hunters as who-who given in a 

 low monotonous tone. While in the forest near Boca de Cupe one 

 afternoon I heard a slight rustling sound, and looking up beheld 

 several curious little faces peering out of a dark hole about 15 feet 

 from the ground in the trunk of a tree. After backing away a few 

 steps I fired a shot into the hole and on examining the tree found that 

 three of these monkeys had dropped to the ground inside the trunk, 

 whence they were extracted by enlarging another hole. A native 

 hunter described finding an adult and several young under similar 

 circumstances. Anthony (1916, p. 374) records examples from 

 Boca de Cupe and Tapalisa of which he says : " Although my speci- 

 mens were taken in southeastern Panama, no material differences 

 between them and the type from Gatun are evident. The type is less 

 richly suffused, but this difference is probably not outside the limits 

 of individual variation." 



Specimens examined: Boca de Cupe, 4 1 ; Cana, 3; Gatun (type 

 locality), 4; Tapalisa, 7. 1 



1 One in Amer. Mus. Nat. Hist. 



2 Collection Amer. Mus. Nat. Hist. 



