Monday, March 14, 2016

Chimp ID: Pearl and her infant Flocke

During the year, I will introduce individual chimps and show how we came up with a specific match. Following is irregular series, you can learn what to look for when comparing two chimps, how to deal with different camera angles and black-and-white footage, and how hard it is to identify infants and often even juveniles. 

Today’s Chimp ID has been very easy matching as we almost immediately recognized this chimpanzee’s most characteristic trait. It all started with a discussion about a distant “pale female” with a dependent infant, mostly carried dorsally (i.e., on the back).

Chimpanzees are born with light-colored faces that darken with age unlike gorillas and bonobos who are born with their dark-colored faces. Depending on subspecies and region, we expect infants and juveniles to have light-colored faces (sometimes with darker eye-masks already early in life), but it is seen less often in adults. As we observed this “pale female” with an infant, this suggested that she was rather an adult. So, her light-colored face was unusual and something to look for.

The "pale" face
With the first close-up, it became clearer that the “paleness” seemed to be an extensive de-pigmentation of her face, brows and ears. It shines almost white with some bigger freckles. In a later video, we could see that both hands are affected too. Although her untypical face made several of us concerned, overall she did not look sick or suffering. Her baby appeared healthy and lively. Some of us noticed frequent slow-swinging head movements which could possibly indicate bad vision or perhaps are just caused by less protection against the glaring sun due to the skin condition or are from some other cause entirely. Unfortunately, her skin condition seems to be changing over the course of one year. While the de-pigmentation has already been fully present when video footage started; a year later one could see that the ears have thickened and crumpled. Yet, her appearance was still robust and she seems to be able to take care of her infant. We also did not notice any other chimps with similar symptoms suggesting that whatever is afflicting her, is not spreading across the community.

Because of her pale complexion, volunteer Snorticus named her Pearl. We named her infant Flocke (the German word for flake), because of its fluffy hair-do.

Another interesting point in this match is that – after an observation of citsci moderator jwidness – we were able to reliably identify Pearl and Flocke from the back view, i.e., without even seeing Pearl’s white face. Flocke has a very special way of riding on mom’s back, using always a protuberance from the female to support the right foot while they walk.

Back view (detail): notice Flocke's right foot seeking support
All videos of Pearl and Flocke can be found in this collection.

You can join the matching discussions at Chimp & See!

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