1738, from a Bantu language of Angola (compare Tshiluba kivili-chimpenze “ape”). Short form chimp first attested 1877.
There was a fruiting mango tree in the camp. Chimpanzees had wandered through for a feast every day. We had kept a respectful distance so as to keep our germs to ourselves, now that we had passed our quarantine period we could follow them more closely.
My first full day with them was with the Sonso group, named for the river than ran close to the camp. This was the first group to be habituated and could usually be found without too long a hike.
The aim was to spend long periods with a target individual recording their every activity in ten minute blocks. Their daily life can be summarised in a list of eating, traveling, resting, grooming and sorting out their social life – just like ours.
So far as eating goes, chimps like ripe fruit. They supplement this with young leaves and will also eat flowers. They will ingest clay occasionally. They drink mainly from puddles in tree hollows but we saw a few drink from a stream which is where they found their clay. They also like to eat monkeys.
They travel with ease along the ground or through the trees. They climb by putting their hands beyond the tree trunk, their feet go on the near side. They are expert at making the more slender trees sway until they can make a transition from one tree to the next. And they make frequent use of outer branches to slow their rate of descent towards the ground or a more rigid branch. Their internal map is in 3D, we have given up a dimension.
When they are having a break from eating they are often involved with grooming, usually in pairs or groups of pairs.
Their social life seems to be all about status and sex. It involves a lot of noise and showing off. Human parallels might be bikie gangs or drug cartels, big males capable of forming useful alliances will rise to the top. And stay there ruthlessly until toppled from power.
The Sonso group hunted Colobus twice on the day I was with them and were successful the second time. The field assistants were very quick to recognise their intentions. The group spread out around the Colobus troop, some on the ground, some at mid level and some high in the trees, all making some attempt to conceal themselves. Then a couple of individuals go after the monkeys. Colobus tend to all rush in the one direction which may be the reason they are the preferred target … you can stay concealed until the first one goes past then grab the next.
The successful chimpanzee will then rip open the monkey’s abdomen and start eating the entrails, the monkey might still be screaming at this stage.
Whilst the hunting is communal the eating is definitely selfish. A lucky few will get some meat. They will ignore the most pitiful begging of subordinate individuals. Why then take part? It doesn’t take that much effort and you may win the lottery.
The next day it was off to the more recently habituated group. We found them after about two hours roughly 8 km from camp. They passed the morning slowly moving towards camp. Then the afternoon moving away!
They had a female in estrus with them, the alpha male was guarding her very carefully. For all his efforts though it was a subordinate that got lucky whilst the boss was chasing off the number two male. There was a fair bit more hooting and drumming on trees than the day before, tensions were raised, it seemed.
They didn’t hunt and the field assistants told us that they had not hunted in recent weeks.