We humans sometimes collect objects that we consider beautiful and carry them home. For example, we may collect beautifully colored stones or shells when we walk on the beach or may pick up beautiful flowers or leaves in the forest to press in a book. We collect such items not because they have practical use—we do not eat them, we do not sell them, nor do we use them as tools or medicines—but simply to keep them on a shelf.

One item that attracts those who walk in the forest of Mahale, Tanzania, is the beautiful blue-spotted black feathers from the crested guineafowl Guttera pucherani that are often found on the forest floor (Fig. 1).

Fig. 1. Feathers of crested guineafowls collected by the author at Mahale.

It is not surprising that chimpanzees (Pan troglodytes) collect and carry things that are directly beneficial to them, such as food. For example, chimpanzees at Mahale sometimes collect five or six lemons from a tree, carrying one in the mouth, one in each hand and foot, and perhaps one more in the groin pocket. So burdened, they cannot walk very far, but may just climb out of the tree and eat the fruit nearby. They also carry various food items between their lips, in a hand or foot, on the back or head, or in the groin or neck pocket, or drag food with one hand when they have to catch up with other chimpanzees¹. Another example of collecting and carrying at Mahale has to do with fishing tools: chimpanzees sometimes prepare these tools at some distance from an ant nest and carry them for up to 70 meters².

Immature chimpanzees sometimes carry objects that are not related to feeding. During play, they often transport objects such as twigs¹. They may carry twigs, logs, tree bark, colobus skin, and human artifacts as if they were carrying “toys” or “dolls” ^3–5. Researchers consider such objects “toys” because juvenile chimpanzees often handle them in a playful manner, such as hitting them, tapping them, or putting them on their head, while showing a typical play face. Such “toys” usually do not attract adults, but only infants and juveniles show interest and often play tug-of-war with these objects.

Here, I would like to report a case in which an old female chimpanzee calmly collected several guineafowl feathers and carried them for more than 30 minutes without displaying any emotional expressions, such as a play face.

OBSERVATIONS

At 10:36 am on 11 October 2009, when I was observing an adult female called Cynthia, my research assistant noticed that an old female called Wakusi (estimated to be 48 years old at the time of observation) was holding two or three guineafowl feathers in her left hand. As we observed her, she walked a bit with the feathers in her hand and picked up two more feathers that happened to be on the trail we were observing. Now carrying four or five feathers in her hand, she kept walking as the other chimpanzees headed north. We followed her to observe the consequences.

At 10:41, Wakusi copulated with a 9-year-old adolescent male called Emory while holding the feathers in her lips. Then, we lost sight of her briefly while we waited for other chimpanzees sitting on the trail to depart. When we caught up with her at 10:44, she was lying on the trail with five individuals close by. She still had the feathers in her left hand, and Emory looked at them. Cynthia’s 1-year-old infant appeared to become interested in what Wakusi had in her hand. Wakusi gently put the feathers in her groin pocket and continued lying on the trail. The infant went closer to Wakusi to look at her groin area where she had put the feathers. Wakusi took out the feathers with her left hand (Fig. 2) and then returned them to her groin pocket. The infant looked at Wakusi’s belly again and then went to her backside. When the alpha male Pimu began to groom Wakusi, the infant went to Wakusi’s ventral side and took the feathers out of her groin pocket. Although Wakusi moved her hand toward the baby slightly, she did not attempt to retrieve the feathers. The infant sniffed and licked the feathers, but discarded them after a while when its mother was about to depart.

Fig. 2. Wakusi lying supine with the guineafowl feathers in her hand. Cynthia’s baby is sitting in front of her facing Wakusi. In the line drawing of Wakusi, the feathers are painted black.

At 10:51, when the alpha male stopped grooming and left, Wakusi was left alone for a while. As she got up, she picked up three feathers one by one with her hand, put them between her lips, and departed into the bush. As she moved through the bush, she again presented to Emory and copulated with him, still holding the feathers in her lips. As she and other chimpanzees moved on in the dense bush, we could not observe her continuously, but when we caught up with her, she had the feathers in her hand, between her lips, or in her groin pocket.

At 11:12 am, Wakusi and some others departed in some haste, and again we lost sight of her because other chimpanzees were barring our way. At this time, she still had the feathers in her mouth. When we reached the trail where she had just passed, I found one guineafowl feather on the ground; its proximal end was wet with saliva (Fig. 3). When we found Wakusi with a party of chimpanzees feeding on a Ficus tree at 11:35, she no longer had the feathers.

Fig. 3. A guineafowl feather left by Wakusi with saliva on the proximal end.

Wakusi carried the guineafowl feathers for at least 36 minutes. This may be an idiosyncratic behavior, although no similar behavior by her had previously been observed, despite the fact that she has been identified and observed for more than two decades. Given that she picked up the feathers from the ground at least twice, it could be said that she had an intention to collect and keep them for a while. However, it is difficult to know why she did so.

It is unlikely that Wakusi assumed that the feathers represented bird meat. A guineafowl egg was once observed to be eaten at Mahale, and other terrestrial birds such as francolins and domestic chickens were also caught and eaten several times⁶. Therefore, it is possible that the chimpanzees consider guineafowl as prey. However, when I observed chimpanzees eating other bird species, they first discarded the feathers, and none showed interest in the discarded feathers, although plenty of feathers were available. Therefore, it is unlikely that chimpanzees show interest in feathers for this reason. In addition, Wakusi never sniffed or licked the feathers.

The feathers did not seem to be like “toys,” either, because Wakusi did not show any attempt to manipulate them in a playful manner, but just kept holding them in her hand, lips, or groin pocket. Although one adolescent male showed slight interest, and one infant eventually handled them in a playful manner (so, they could have been a “toy” to the baby), Wakusi herself never attempted to play with them or showed a play face. Consequently, it is difficult to say that Wakusi considered them toys in the usual sense.

The old female chimpanzee just calmly collected and carried several bird feathers. It is difficult to guess whether she found them beautiful, as humans do. She did not seem to collect the feathers for a particular functional reason. Consequently, can we say that she collected them just because she liked them? Many archeologists assume that art or symbolic representation only appeared in modern humans about 50,000 years ago⁷. However, because the underpinning aesthetic mentality cannot be fossilized, it is possible that similar aesthetic sensibility had evolved much earlier in the chimpanzee-human clade.

REFERENCES

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