206 
NATURAL HISTORY. 
Nevertheless. I could perceive that when they were pleased, the form of the lips differed a little froii* 
that assumed when they were angered. If a young Chimpanzee be tickled, and the armpits are 
particularly sensitive to tickling — as in the case of our children — a more decided chuckling or laughing 
sound is uttered, though the laughter is sometimes noiseless. The corners of the mouth are then drawn, 
backwards, and this sometimes causes the lower eyelids to be slightly wrinkled. But tliis wrinkling 
which is so characteristic of our own laughter, is more plainly seen in some other Monkeys. The teeth 
in the upper jaw in the Chimpanzee are not exposed when they utter their laughing noise, in which 
respect they differ from us ; but their eyes sparkle and grow brighter, as Mr. W, L. Martin, who has 
particularly attended to their expression, states. 
“ Young Orangs when tickled likewise grin and make a chuckling sound, and Mr. Martin says 
that their eyes grow brighter. As soon as their laughter ceases, an expression may be detected 
passing over their faces, which, as Mr. Wallace remarked, may be called a smile. I have also noticed 
something of the same kind with the Chimpanzee. Dr. Duchenne— and I cannot quote a better 
authority— informs me that he kept a very tame Monkey in his house for a year, and when he gave it 
during meal times some choice delicacy, he observed that the corners of its mouth were slightly raised* 
thus an expression of satisfaction, partaking of the nature of an incipient smile, and resembling that 
often seen on the face of man, could be plainly perceived in this animal. 
“ The Cebus azcirte , when rejoiced at again seeing a beloved person, utters a peculiar twittering 
sound. It also expresses agreeable sensations by drawing back the corners of its mouth, without 
producing any sound. Bengger calls this movement laughter, but it would be more appropriately called 
a smile. The form of the mouth is different when either pain or terror is expressed, and shrill shrieks 
are uttered. Another species of Cebus in the Zoological Gardens when pleased makes a reiterated shrill 
note, and likewise draws back the comers of its mouth, apparently through the contraction of the same 
muscles as with us. So does the Barbary Ape ( Innas ecaudcitus) to an extraordinary degree ; and I 
observed in this Monkey that the skin of the lower eyelids then became much wrinkled. At the same 
time it rapidly moved its lower jaw or lips in a spasmodic manner, the teeth being exposed ; but the 
noise produced was hardly more distinct than that which we sometimes call silent laughter. Two of the 
keepers affirmed that this slight sound was the animal’s laughter, and when I expressed some doubt on 
this head (being at the time quite inexperienced), they made it attack, or rather threaten, a hated 
Entellus Monkey living in the same compartment. Instantly the whole expression of the face of the 
Inuus changed ; the mouth was opened much more widely, the canine teeth were more fully exposed, 
and a hoarse barking noise was uttered. 
“ The Anubis Baboon was first insulted, and put into a furious rage, as was easily done by his 
keeper, who then made friends with him, and shook hands. As the reconciliation was effected the 
Baboon rapidly moved his jaws and lips up and down, and looked pleased. Two or three species of 
Macacus, and the Cynocephalus niger , draw back their ears, and utter a slight jabbering noise when they 
are pleased by being caressed. With the Cynocephalus the corners of the mouth are at the same time 
drawn backwards and upwards, so that the teeth are exposed j hence this expression would never be 
recognised by a stranger as one of pleasure. The crest of long hairs on the forehead is depressed, and 
apparently the whole skin of the head drawn backwards. The eyebrows are thus raised a little, and I 
the eyes assume a staring appearance. The lower eyelids also become slightly wrinkled, but this 
wrinkling is not conspicuous, owing to the permanent transverse furrows on the face. With Monkeys 
the expression of slight pain, or of any painful emotion, such as grief, vexation, jealousy, &c., is not 
easily distinguished from that of moderate anger, and these states of mind readily and quickly pass into ♦ 
each other. Grief, however, with some species, is certainly exhibited by weeping. A woman who sold 
a Monkey to the Zoological Society, believed to have come from Borneo (Macacus vnaurus ), said 
that it often cried, and Mr. Bartlett, as well as the keeper, Mr. Sutton, have repeatedly seen it, 
when grieved, or even when much pitied, weeping so copiously, that the teal's rolled down its 
cheeks. There is, however, something strange about this case, for two specimens subsequently 
kept in the Gardens, and believed to be the same species, have never been seen to weep, though they 
were carefully observed by the keeper and myself when much distressed and loudly screaming. 
Bengger states that the eyes of the Cebus azarce fill with tears, but not sufficiently to overflow, when 
it is prevented getting some much-desired object, or is much frightened. Humboldt also asserts that 
