Chimp & See Talk

How many chimps are there?

  • AnLand by AnLand moderator

    I have some quite naive questions, but I just don't know:

    1. Per site: Is this one community / family (whatever you call a group of chimps)? Do they all know each other and interact frequently? I am quite astonished to see so many "lonely" chimps or single families (mothers with children) and not bigger groups of chimps. I always thought about chimps in groups. Are there others around we just cannot see?
    2. How many different chimps do we expect per site? Do we expect to see each chimp at least once or is this (in the camera traps) a tiny fraction of what could be seen at this site?

    I would appreciate a short orientation about this. Thanks!

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  • MimiA by MimiA scientist, moderator

    Hi AnLand

    Prepare for a bit of a novel 😉

    When we set up our sites we attempt to have 1 entire chimp community in our data collection zone (if you are super curious as to how we do this you can check out our data collection protocol here: http://panafrican.eva.mpg.de/english/approaches_and_methods.php) But in short, the site managers will walk through the forest on what are called reconnaissance walks (aka recces) and record any and all chimp signs (nests, foot prints, dung, feeding remains, vocaliazations,..) they detect. We aim to have around 50km2 recced by the time they are done. We know forest chimps usually have around 25km2 home ranges so based on that assumption and the localization of chimpanzee signs we try to figure out where the center(s) of activity is for the chimps and place our data collection area so that at least 25km2 is covered and most of the areas of chimp activity are covered. The exception to this rule is for savannah chimpanzees (these videos will be uploaded in the future) their home ranges are much larger than forest chimpanzees and so we have up to an 80km2 data collection zone for savannah chimps.

    In some cases we realize we have peripheral members of other groups but this is OK since we will be able to figure this out with downstream analyses (we hope).

    Chimpanzees have overlapping territories at their peripheries so this is expected. You may have heard about chimpanzees going out for patrols and doing incursions? This is when the chimps walk the periphery of their territory and try to hear what the neighboring group is doing. If there are nearby members of the other group when they are on patrol they will enter the neighbouring territory and often attack the neighbouring chimps (or sometimes mate with those neighbouring females - depending on which chimpanzee subspecies we are talking about) Here is a clip of East African chimps (I am pretty sure this is the Ngogo study community in Uganda) going on patrol and then proceeding with an incursion: https://www.youtube.com/watch?v=a7XuXi3mqYM

    Chimpanzees live in a multi-male, multi-female, fission-fusion society. So the group is actually rarely (I think maybe even never) seen all together. The chimps usually hang out either alone, females and just their offspring or in small parties. These parties are not fixed so everyday you go out into the forest any given chimp can be with any other given chimp. The different subspecies of chimpanzees have different affinities for one another. When there is a hunt,r a very abundant fruit tree or it is nut cracking season the party size will become larger, when a female is in estrous then more males will usually be around her looking for a mating opportunity. So what you are seeing is exactly what we know about how chimpanzees interact with each other. They are territorial though so individuals stay within their territory boundaries (with a few exceptions as mentioned above). Chimps are also patrilocal (aka male philopatric) - males spend their entire lives in a group whereas females leave the group when they reach sexual maturity (again, with a few exceptions)

    some light reading: http://www.eva.mpg.de/primat/staff/boesch/pdf/behav_eco_soc_fiss_fus.pdf

    Our expectation for the cameras is to hopefully see each chimp at least once, the placement of the cameras spans the whole territory hopefully. We ask the site managers to aim for 200 chimpanzee videos per site (usually we get about 10,000 videos total so a small percentage is chimp videos) and there are about 20-100 chimps at each site. Of course, each video can contain multiple chimps and some chimps will have affinities for some areas and not others, so it is hard to make a hard and fast rule to answer your second question - but hopefully that helps orient you a bit more.

    As you can see I can talk about this all day - so I am happy to write more if you have more questions 😉

    Posted

  • Snorticus by Snorticus

    Thank you for asking about this, AnLand. While tagging for just a few days, I haven't run across very many chimp clips, but lots of other animals - so this explains that and so much more.

    Thanks MimiA for that tutorial! Such an interesting project to participate in, though I sometimes feel a little guilty that I am doing my part in my air conditioned house. ;-D

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  • AnLand by AnLand moderator in response to MimiA's comment.

    Hi @MimiA,

    thank you so much for that explanation. It is now for me much clearer what we are seeing, what is expected and how the places we do see are chosen.

    First, I did not know about the patrols and the end of the linked video is - well - uncomfortable to watch on a Sunday morning. Poor youngster! Also in studying the guide you linked to, I have to admit that I did not know that chimps eat meat at all and that this is one important question of the overall study. I saw once (at the zoo) that chimps hunted successfully a bird, but it did not occur to me that they might just eat it afterwards ... But I also think, this is not in the focus here at Chimp&See.

    I am in general very impressed about the amount data your field teams are supposed to collect. In the videos here you see sometimes the collection of samples (nuts, mostly) or taking pictures of a tool (yes, they did it correctly with a ruler next to the tool!), but there seems to be much more data collection going on that we do not see here. So, I really hope that the data (and also the people here) can help you answer that questions. Thanks again, I will certainly have more questions later ...

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  • MimiA by MimiA scientist, moderator

    Have you seen the movie Chimpanzee by Disney that came out last year? It was shot in Tai (Ivory Coast), Kibale (Uganda) and Gombe (Tanzania) forests and shows viewers a lot about chimpanzee behaviour and culture. The narration is not my dream narration but the images are amazing and you get to see real wild chimpanzee behaviour. The story is also a true story of adoption by a male individual of an orphaned juvenile which happens quite often in the Tai chimpanzee population. https://www.youtube.com/watch?v=qv-3usEv3PA

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  • Snorticus by Snorticus in response to AnLand's comment.

    I wondered what they were measuring on the ground to the left of a tree trunk in a clip yesterday - so you think it was a tool? Interesting.

    Posted

  • ksigler by ksigler moderator

    Just wanted to say this is fascinating thread. Clearly chimp societies are much more complex than we can observe in a few video sequences. I have to admit, though, I'm a little thankful we haven't gotten the brutal honesty of post-patrol feasts that the youtube clip shows -- eek. 😛

    If anyone hasn't visited the PanAf Programme website @MimiA linked above, I highly recommend it. Lots of info about this project, as well as photos and research interests of some of our scientists here!

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  • Snorticus by Snorticus

    Agreed, that clip was brutal and it's interesting that the last shot is two chimps so politely and calmly sharing a piece of the carcass.

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  • Snorticus by Snorticus

    Is this MimiA? The possible knowledge/info gain from this method is so cool! How exciting that this is being studied in this way. I worry about all the magnificent animals dwindling on the planet and how humans can work to reverse that.
    From http://panafrican.eva.mpg.de/ site:

    "My PhD focused on samples from Loango National Park, Gabon and demonstrated that genetic capture-recapture is an accurate and precise method for ape population estimation and an improvement over traditional methods of estimating ape population size. Furthermore, I was able to show that minimum number of ape groups, their composition and ranging patterns as well as individual cases of dispersal, group dissolutions and formations can also be obtained from the same samples. For gorillas, I was also able to establish kin relationships for several of the groups and to test hypotheses about kin structure across groups in the species, all from non-invasively and opportunistically collected samples."

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  • MimiA by MimiA scientist, moderator

    Thanks for the plug guys 😃

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  • Snorticus by Snorticus

    You are welcome. I'm just a retired gal who used to work as a photographer so I know nothing about the scientific community or the methods. Am enjoying getting a look at your world through this project and through all the links and discussions.

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  • AnLand by AnLand moderator in response to Snorticus's comment.

    Hi @Snorticus, here is a nice video of measuring a tool: ACP00042nc

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