DuMond Conservancy's Team Aotus

Tuesday, June 4, 2013

Who's Who in the Owl Monkey Woods? 

When you do research it’s very important to be able to identify the individuals that you are observing quickly and accurately. Depending on the type of research you are conducting the level of individual identification varies. In some studies just differentiating between both sexes is enough however when studying owl monkeys it is impossible to tell apart a male from a female due to a lack of sexual dimorphism in this species. So in this case distinct features such as physical markings, scars, and differences in body structure may be used in identifying the subject.  At first when you start observing you have to try to spot noticeable physical differences of the individuals in the enclosure you may be watching. Because owl monkeys are active at night and the observations take place at night it’s hard to tell them apart by things like a slightly darker coat of one compare to the others house in the same enclosure, and because owl monkeys are so agile and quick it also gets challenging trying to identify them by their faces or the trident marks on the top of their heads, many times the monkeys are not facing you or keep still long enough for you to get a proper id and if these are the only physical characteristics you are basing your id on it may lead to problems in the future.

Owl monkeys are notoriously difficult to identify. Can you spot the male and female in this photo? It is very difficult to know without knowing the physical traits of each monkey. 

The most helpful physical characteristics to take note of before the start of the observation (for me at least) are; the size difference between the monkeys, if its large it could be a great help in identifying them. The tails are always good to look at, some of them being very short compare to their enclosure partners. The state of the coat should be noted also, some monkeys will have patches of fur missing from over grooming, nervous habits, or scars (this last one is rarely seen with this group of owl monkeys,) or the fur in the tail may be very different from their companions. Some of the monkeys also have large throat sacks that are very easily spotted. Some also have advance cataracts that give off a dull white reflection when the light hits them. If you look at Lucifer and Creamy you can see this large size difference, same with georgie and her companion. The most distinct difference in tail length is between Iago and Nina (Nina having the shortest tail in our collection). Cloe’s coat is a very striking example of a difference in coat estate, her lack of fur is due to over grooming by her partner which is thought to get better once she is switch enclosures. If you want to see a difference in the tail fur you have to look at Retsina’s family who has very distinct patterns from each other and the rest of the owl monkeys. My favorite example for a distinct throat pouch is Santa’s, he has a large white throat pouch that looks like a beard and makes him look like Santa Clause (which is why he was probably named this, I haven’t asked yet).

 These are all characteristics that are easy to see at night and can be spotted in an instant whenever the monkeys are not jumping around at incredible speeds, you could be following them intently with your flashlight thinking that you will never lose sight of them and with a quick motion they are gone and you are left searching all over for them and when you find a monkey if you can’t id them before they jump again your whole research may be fill with holes. This is more of a problem with the juveniles who are very active the adults tend to move with slower more calculated movements (unless they are in an enclosure with juveniles then they tend to get a little agitated as well). Once you have watched an enclosure enough times you can begin to identify the monkeys in it by their behavior. There are behaviors that can be peg to individual monkeys. Connie and Alled for example do backflips, Lucifer is always hooting lowly, spruce likes to hang from the roof in a unique manner (it looks like a v-shaped hammock) while her partner (dodge) has a designated spot under their box where you can always find him, Crunchy likes to walk hanging from the roof, and Betsy urine washes frequently. The lack of rapid movement can also be an identifying characteristic, as is the case for Rhetz since he is blind he moves very slowly.    

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