While our research has focused on the lives of the Sonso chimps for over 20 years, there are many other communities in the forest several of whom are neighbours to our group. These groups are all unhabituated and normally we only know they’re around by watching the behaviour of the chimps we are following; but recently the group to the East has been getting bolder, and we now regularly see them on forays deep into Sonso territory.

the fig trees are always very popular

fig trees are always very popular

Chimpanzee communities have core home areas and a wider territory which they actively defend from other groups; but these ranges are large (Sonso is considered a small range but is still over 10 square km) and the chimps can’t be everywhere at once. Large fruiting trees in the periphery of one group’s range are a particularly tempting target for neighbouring groups to raid. It would be relatively easy for a group to sneak in and pilfer the fruits from a neighbour’s tree if it wasn’t for one small problem – chimpanzees are extremely noisy eaters. A chimp surrounded by dozens of figs will still scream blue murder if he accidentally drops the one he happens to be eating; even just approaching a large tree can be reason enough for loud excited hoots which carry through the forest. The home-group soon cotton on to the fact that there’s something amiss and (depending on who’s around) then hurry over to see what’s what.

even fluffy little Zed did more than Nick!

even fluffy little Zed did more than Nick!

These inter-group encounters are always noisy with lots of screaming, stamping and branch shaking; and they can get very aggressive. Over the past few months the group to the East have been turning up in the Sonso group’s core home area only a few hundred meters from our camp. The situation has not been helped by the fact that recent deaths have left us with only 3 large adult males (Nick, Zefa and Bwoba) and Nick the alpha male is more likely to be found leading the retreat than defending the group’s precious resources. An encounter last year saw him drop 40m out of a tree like grease-lightning, and take-off – leaving the women and children to deal with the invaders, even tiny Zed and the very pregnant Kutu did a better job at trying to scare off the raiders! Admittedly the neighbouring group seems to have some particularly huge adult males but his behaviour to date has not inspired the confidence you want to feel in an alpha male.

Then only a few days ago a large group of Sonso chimps were feeding in the morning when they heard calls from East – they immediately rushed over and for the first time it was the Sonso chimps who succeeded in driving away the Eastern group. In the noise and chaos that ensued an Eastern female seemed to get left behind; the Sonso females immediately attacked her – biting and dragging her along the ground. Nick arrived (as usual he was ‘missing’ from the initial attack…) and appeared to support the stranger female – they ended up driving him off before he managed to come back and sit down next to her. The rest of the Sonso group then moved off leaving them behind.

Chimpanzee females are sometimes taken hostage from other groups and can then integrate into the new community. Obviously for the Sonso males any new females they can win over is a good thing, but for the Sonso girls a new female just represents competition for the limited resources available to them and their children, so it’s rarely an easy experience for the new addition.

It was great to see our chimps finally stand up for themselves and drive the raiders back out of their territory, but with food getting more scarce now at the end of the dry season this certainly won’t be the last we see of the Eastern group.

For many years scientists thought that chimps, like gorillas or orangutans, were predominantly vegetarian; but we now know that they can be keen and active hunters in a manner more comparable to their closest relative – us! The chimps at Sonso have been observed over the years to feed on several species of monkeys as well as some of the other small mammals in the forest like the duikers (a small forest antelope), but this seemed to be a relatively rare occurrence, only reported once or twice a year. However, over the past year the Sonso chimps seem to have developed a taste for the Black and White Colobus monkeys, at times hunting them on a daily basis. While rather unfortunate for the colobus monkey’s (!) it has led to some fascinating opportunities for us to observe both how the chimps go about the actual hunt itself, and then the social intricacies of who gets what and who shares with whom as they feed on the meat in the aftermath. 

It’s definitly the younger adult males who are doing all the hard work  (though some of the girls like Nora do get in on the action) – colubus monkeys throw themselves with almost reckless abandon through the upper canopy which can be 40m above the ground and it takes an energetic and brave chimp to catch one!

The alpha male Nick with a small monkey

The alpha male Nick with a small monkey

Despite doing the lion’s share of the work, these youngsters certainly don’t get a lion’s share of the meat. When hunting they tend to knock the monkeys out of the trees so that they fall below; here, watching keenly from the ground or lower branches, one of the older dominant males waits to literally have their meal drop right into their lap! Once they have got a hold of it, they guard it jealously only occasionally allowing small tidbits to escape to a favoured ally or a female in oestrus. 

youngsters like Hawa are lucky to get a scrap of bone

youngsters like Hawa are lucky to get a scrap of bone

 

For the younger chimps their best chance of getting a tasty bit of colobus is when they’re in a smaller party on their own – but even then there are no guarantees. Last Friday Zalu and Frank teamed up together with Zalu chasing a young colobus into an adjacent tree where Frank caught it; however, poor Zalu then lost out completely when Frank went on to share it all with Kato. While Zalu (at 13) is much older and bigger than the 9 year old Frank, his gentle and laid back temperament let him down leaving him no match for the cocky little Frank and the much more dominant Kato.

It’s been so interesting to see over the past year how more individuals in the group are getting in on the hunting action. The group also seems to be getting more proficient, at times now even taking on the larger adult monkeys. We’ll definitely be keeping a close eye on this behaviour to see what happens in the future.

New projects

February 11, 2009

Hello everyone,

A little update on the research side of things out at Sonso. As we mentioned in December, we said a sad goodbye to some long-term students as they wound up their projects last year – and we now have two very exciting new PhD projects which started in January. Thibaud Gruber (University of St Andrews) will be working on causal cognition and intentional communication – focusing on tool use and the content and meaning of grunts. While Tanja Kaller (University of York) will be working with both chimpanzee and human infants to look at the coordination of attention in mother-infant pairs. Both of these studies will be breaking new ground in the understanding of wild chimpanzee behaviour and we can’t wait to find out what new insights they’ll give us into the lives of our Sonso chimps. To see more about these and the other ongoing projects at Sonso check out our current research page here.

It’s a sad fact that many of our chimpanzees in Budongo have permanent serious injuries left after they are accidentally caught in the snares local hunters leave in the forest for small antelope and pigs. You can see the effects this has and some of the work we do in trying to combat this terrible problem here; however, despite our best efforts chimps do still occasionally get caught. Trying to intervene to remove a snare from a wild chimpanzee is a complex and dangerous procedure in itself – and it’s something that has to be decided on an individual case basis. Over the past year our resident vet Tonny Kidega, along with his collaborators in the Uganda Wildlife Authority (UWA) and the Jane Goodall Institute (JGI), has worked extremely hard to develop safer procedures which would allow intervention in a higher number of cases.

Tonny and the team hard at work

Tonny and the team hard at work

We are very happy to report that on the 20th of January Tonny and the team successfully freed a young female chimpanzee from a mantrap which would have almost certainly resulted in the loss of her hand and probably her death if left unattended. She was a member of the community which lives in the Bulindi forest fragment on the edge of Budongo. On the 19th a local farmer contacted BCFS in the evening to report that she was trapped; early the next morning the team were able to locate her and dart her, they could then examine her in detail and were able to remove the heavy trap from her wrist. The trap had not yet broken any bones, and as a young chimp we are very hopeful that there will be no permanent damage and she will make a full recovery. You can read Tonny’s full report here. Congratulations to Tonny and everyone involved, this is a fantastic achievement and is another great step forward in our efforts to ensure that future generations of chimps never have to suffer from the devastating injuries snares inflict. (Photos courtesy of Kylie Mcqulater).

Much better now! the young girl should make a full recovery

Much better now! the young girl should make a full recovery

The terrible mantrap snare on the young chimps wrist

The awful mantrap on the young chimps wrist

%d bloggers like this: