or weak-minded rats having been continuously destroyed by him. It is,
however, possible that the success of the common rat may be due to its
having possessed greater cunning than its fellow-species, before it
became associated with man. To maintain, 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. We have seen 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. (37. Savage and Wyman in Boston Journal of Natural
History, vol. iv. 1843-44, p. 383.) Rengger (38. Saugethiere von
Paraguay, 1830, s. 51-56.) 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
afterwards 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. The
tamed elephants in India are well known to break off branches of trees
and use them to drive away the flies; and this same act has been
observed in an elephant in a state of nature. (39. The Indian Field,
March 4, 1871.) I have seen a young orang, when she thought she was
going to be whipped, cover and protect herself with a blanket or straw.
In these several cases stones and sticks were employed as implements;
but they are likewise used as weapons. Brehm (40. Thierleben, B. i.
s. 79, 82.) 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 mountains to plunder the fields,
they sometimes encounter troops of another species (C. hamadryas), and
then a fight ensues. The Geladas roll down great stones, which the
Hamadryas try to avoid, and then both species, making a great uproar,
rush furiously against each other. Brehm, when accompanying the Duke of
Coburg-Gotha, aided in an attack with fire-arms on a troop of baboons
in the pass of Mensa in Abyssinia. The baboons in return rolled so many
stones down the mountain, some as large as a man s head, that the
attackers had to beat a hasty retreat; and the pass was actually closed
93