Chap. II. 
MENTAL POWERS. 
51 
as to nearly all the less cunning or weak-minded rats 
having been successively destroyed by him. To main- 
tain, independently of any direct evidence, that no 
animal during the course of ages has progressed in 
intellect or other mental faculties, is to beg the question 
of the evolution of species. Hereafter we shall see that, 
according to Lartet, existing mammals belonging to 
several orders have larger brains than their ancient 
tertiary prototypes. 
It has often been said that no animal uses any tool ; 
but the chimpanzee in a state of nature cracks a native 
fruit, somewhat like a walnut, with a stone. 23 Rengger 24 
easily taught an American monkey thus to break open 
hard palm-nuts, and afterwards of its own accord it 
used stones to open other kinds of nuts, as well as 
boxes. It thus also removed the soft rind of fruit that 
had a disagreeable flavour. Another monkey was taught 
to open the lid of a large box with a stick, and after- 
wards it used the stick as a lever to move heavy bodies ; 
and I have myself seen a young orang put a stick into 
a crevice, slip his hand to the other end, and use it in 
the proper manner as a lever. In the cases just men- 
tioned stones and sticks were employed as implements ; 
but they are likewise used as weapons. Brehm 25 states, 
on the authority of the well-known traveller Schimper, 
that in Abyssinia when the baboons belonging to one 
species ( C . gelada) descend in troops from the moun- 
tains to plunder the fields, they sometimes encounter 
troops of another species ((7. hamadryas ), and then a 
fight ensues. The Geladas roll down great stones, which 
the Hamadryas try to avoid, and then both species, 
23 Savage and Wyman in 1 Boston Journal of Nat. Hist.’ vol. iv. 
1843-44, p. 383. 
24 4 Saugethiere von Paraguay/ 1830, s. 51-56. 
25 < Thieiieben/ B. i. s. 79, 82. 
