Monday, June 25, 2012

It's hunting season yet again at Fongoli!

Back at Fongoli again – June 10, 2012

The first day back is always exciting, but the fact that the whole community of 32 Fongoli chimpanzees was together near Sakoto ravine, the site of their soaking pool and cave, was an extra treat! There were several hard rains in May, but there had been a dry spell for almost two weeks, so the chimps were localized around the pool, drinking and doing some soaking daily. The water level was not very high in the pool, and the water was pretty dirty, as the leaves and other detritus that gathered there since the pool was full of water some 6 months previously had not yet been washed out. Still, a few die-hard water babies like Bandit sat in the pool for up to 20 minutes at a time, vacating only when a dominant individual came to get a drink and cool off.

Tool-assisted or “spear” hunting coincides with the onset of the rainy season, and my main field assistant Michel Sahdiako has noted that adolescent female Sonja has already tried her hand a couple of times. No bushbabies yet, although she received an unhappy surprise when she roused a genet during one bout! I expect the genet gave her a shock because it was so much larger than a bushbaby and would have had to run out past her, unlike a bushbaby, which would have hopped off, had it been so lucky to escape. The Fongoli chimps don’t eat genets, a catlike creature that is related to the mongoose family. I imagine this is the case because of their unpleasant scent glands, but we have observed a few of the chimps capture and play with young genets – a scenario that ultimately did not end well for the genets!

At any rate, the first day I was back with the Fongoli chimps, adolescent female Fanta was indeed so kind as to give me a glimpse of bushbaby hunting! Before the chimps got very far from Sakoto in the morning, she fashioned a tool from a live tree branch, trimmed off the side branches and leaves and modified the tip with her teeth. No luck for Fanta yet either, but she is the most prolific Fongoli chimpanzee hunter, accumulating over 23 bouts now – at least according to our records. She supplanted adult female Tumbo from the top position, but Tumbo is still the most successful hunter, capturing a bushbaby in over one-third of her hunts.

The next day, true to form, Sonja decided to hunt again. She spent quite a lot of time, making, using and discarding four different tools, before she abandoned the cavity. From her behavior, I deduced that she did not detect bushbaby presence, which is what I believe accounts for most failed hunts, although there have been times when it appeared clear that a bushbaby was present but could not be captured. In one case, I was able to climb up and search inside the cavity myself, after Lucille and two other chimps were so obviously vigorous in their attempts that I was sure a bushbaby must be there. There was indeed a very angry and slightly injured bushbaby – it had cuts on its head from the “spear”. I assume it survived, as these cuts seemed somewhat superficial. The bushbaby was not very far down in its cavity, but it appeared to have a side area that it could squeeze back into, avoiding the full effort of the chimps’ jabbing and stabbing.

On my third day back with the chimps, a hard rain and windstorm swept up. Bushbaby hunting is sure to start up again with a vengeance now. We normally record between 40 and 50 hunts per year during this season and have over 200 cases now. With this sample size, I hope to be able to discern individual chimpanzee differences, and we can begin to see patterns of learning in the offspring of the female hunters. My field assistant Waly Camara also reported that, about 10 days before I arrived back at Fongoli, he witnessed adult male Bandit and adult female Farafa using the same type of “spear” tools to stab at a leopard hiding in a small cave near their dry season water source! The leopard escaped in that instance.

Finally, an interesting incident also occurred on my first day back, involving adolescent male Lex and a chameleon! The Fongoli chimps are averse to most reptiles – we’ve recorded over 20 such encounters, most with potentially lethal snakes – and the chameleon seems no exception. Lex was intent on following and harassing the little lizard and even tossed it by its tail at one point. Of course, a number of other immature chimps had to come investigate, but juvenile Sounkaro, Lex’s younger sister, was too frightened of the chameleon to do much with it after it tried to bit her. Sonja chased it away, and I’m happy to report it seemed to escape – unhappy, judging from its mottled black and green color, but hopefully none the worse for wear!

P.S. Since I wrote this about 2 weeks ago, we've seen more hunts, so that we now have over 20 so far this year! Sonja and Fanta are in the lead, but subadult female Lily and young adult male Bo are the only successful hunts we've seen so far. K.L. also snagged a bushbaby, but I was unable to detect how he obtained it, so he doesn't make the official list, and he didn't share what appeared to be a younger bushbaby either! On another day, both Lupin and Siberut were seen with captured vervet monkeys, and there was some sharing on that day, however. The chimps also had another interesting reptile encounter - this time with a python! They found it in a small water hole after a big rain, and it was about 2 meters long. They filed by and screamed at it but left without doing much more to it. A lot of excitement during my first 2 weeks back at Fongoli!

The photo above is of some of the 25 or so hunting tools used by the Fongoli chimps so far this year...the one on the bottom of the photo was the tool used by adult male Bandit to try and stab at the leopard!

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