Distribution.—The variation in colour described above is not due to local causes, every variety occurring between the lightest and darkest, in all the regions which this species is known to inhabit. The localities from which it has been recorded are on both the Atlantic and Pacific coasts of Nicaragua; Costa Rica, where it occurs in large numbers from the coast forests up to nearly 7,000 feet on the mountains; Panama, and the U.S. of Colombia.
Habits.—Geoffroy's Spider-Monkey is gregarious and arboreal, frequenting the highest trees of the forest, both in the low country and at high elevations, and living on fruits and insects, but chiefly on the former. Mr. Belt relates that on the banks of the Antigua he saw a valuable tree, the "Nispera" (Achras sapota), growing on the dryer ridges. "It bears a round fruit about the size of an apple, hard and heavy when green, and at this time it is much frequented by the large yellowish-brown Spider-Monkey (Ateles), which roams over the tops of the trees in bands of from ten to twenty. Sometimes they lay quite quiet until I was passing underneath, when, shaking a branch of the Nispera tree, they would send down a shower of the hard round fruit; but fortunately I was never struck by them. As soon as I looked up they would commence yelping and barking and putting on the most threatening gestures, breaking off pieces of branches and letting them fall, and shaking off more fruit, but never throwing anything, simply letting it fall.[[13]] Often when on lower trees, they would hang from the branches, two or three together, holding on to each other and to the branch with their fore-feet and long tail, whilst their hind-feet hung down, all the time making threatening gestures and cries. Sometimes a female would be seen carrying a young one on its back, to which it clung with legs and tail, the mother making its way along the branches, and leaping from tree to tree, apparently but little encumbered by its baby. A large black and white Eagle is said to prey upon them, but I never saw one, although I was constantly falling in with troops of the Monkeys. Don Francisco Velasquez, one of our officers, told me that one day he heard a Monkey crying out in the forest for more than two hours, and at last, going to see what was the matter, he saw a Monkey on a branch and an Eagle beside it trying to frighten it to turn its back, when it would have seized it. The Monkey, however, kept its face to its foe.... Velasquez fired at the Eagle, and frightened it away. I think it likely, from what I have seen of the habits of this Monkey, that they defend themselves from the Eagle's attack by keeping two or three together, thus assisting each other, and that it is only when the bird finds one separated from its companions that it dares to attack it."
Mr. Osbert Salvin met with several of these Monkeys near the town of San Juan del Sur, in Nicaragua. He was walking up the course of a half-dry stream when he came upon a troop of Monkeys which had come to a pool to drink, and were climbing about the low trees on the bank of the watercourse. Most of the troop consisted of Cebus hypoleucus, but with them were several Ateles of the present species, of one of which Mr. Salvin wrote a description as it sat jabbering at him and throwing down sticks from a branch above his head. Mr. Salvin also told Mr. Alston that it was not unusual to see Monkeys kept in confinement in the court-yards of the Spanish houses in Guatemala. Amongst them were occasionally to be seen specimens of Geoffroy's Spider-Monkey; but he always found that they had been brought from Nicaragua or Costa Rica, the species not extending into Guatemala.
III. THE RED-BELLIED SPIDER-MONKEY. ATELES RUFIVENTRIS.
Ateles vellerosus (?) (nec Gray), Scl., P. Z. S., 1871, p. 478.
Ateles rufiventris, Scl., P. Z. S., 1872, p. 688, pl. lvii.; Schlegel, Mus. Pays Bas, vii., p. 182 (1876).
Characters.—Fur rough, upstanding less on the tail than on the body, that on the forehead erect and directed backwards, that on the top of the head long, projecting forward. Face and muzzle, except a black line from the side of the nose and inner corners of the eyes to the cheeks, flesh-coloured. General colour uniform black, but the whole under surface deep bright rufous, this colour extending but slightly on to the inner surface of the limbs. Thumbs entirely wanting.
Differs from A. geoffroyi by its flesh-coloured face and by the two colours of the upper and under sides being clearly defined. Length of body, 12 inches; of tail, 15½ inches.
Distribution.—This species was first discovered on the Atrato river, in Northern Colombia, and has since been found in Panama.
Habits.—The Red-bellied Spider-Monkey is very rare, only one or two specimens having yet been obtained. Nothing is, therefore, known of its habits.