Late nights with the monkeys of Los Arboles

Late nights with the monkeys of Los Arboles

This past summer we had the pleasure to welcome Nicki Guisneuf to the spider monkey project at LAT. Nicki collected data for her master’s thesis from Oxford Brookes University (United Kingdom) from May to July on the nocturnal behavior of spider monkeys, with aim of understanding why the monkeys are sometimes awake at night. Since her time at LAT Nicki has finished and handed in her thesis and she has written about her experiences at LAT below.

I had a great experience in Los Arboles and I’m so thankful I was able to spend time in such a wonderful place with the incredible spider monkeys. Everybody was so accommodating and friendly and I felt so welcome.  

A beautiful photo of a spider monkey in the early hours of the morning.
Worth staying up all night! Photo by Nicki Guisneuf

Having never seen wild spider monkeys before, I was so excited to see them before I arrived.  Although I knew I would see monkeys, nothing prepared me for the moment I first spotted them through the trees on the afternoon I arrived. The time the monkeys arrived in the evenings was so special and I loved watching them interact and the little ones climbing about and exploring away from mum.  

Spider monkeys are considered diurnal, which would mean they sleep all night but, as I’m sure many of you know, they often make noise in the night and we were interested in investigating why this is and what they do.  The aim of the study was to look at possible causes of them waking up at night, so we collected data on rainfall, temperature, daytime temperature, moon phase and other noises.  I was able to continue the work Denise and Coral had started, from the roof of D-17.  Since it was so hot between May and July, the temperature at night did not drop too low and it didn’t get too cold.

Being on the roof at night was fun, especially when the moon was bright, or the beautiful stars were out!  Coffee was my best friend, particularly when the monkeys really were sleeping and there was not much for me to report for long hours in the middle of the night.  One thing that did help me to stay awake was the frequent visits from scorpions!!  I was terrified of them at the start with their creepy little pincers, but I got quite a lot of practice at flinging them of the roof and into the trees. Thanks to Denise for teaching me the technique of the flying lessons! Even so, I was never alone for long with visits from frogs, grasshoppers, spiders, lizards and geckos. 

I am also really fascinated by spider monkey communication and the meanings of the different sounds they make so I also recorded their vocalizations with a microphone to investigate whether their calls had different acoustic structures between night and day.  This also meant I followed them in the forest in the mornings, which is a whole different experience to the night observations!

Nicki recording spider monkey vocalizations in the forests of LAT. Thank you to Instituto de Neuroetología, Universidad Veracruzana and Oxford Brookes University for lending us the recording equipment!  Photo by Denise Spaan

As my first experience of fieldwork, I could not have asked for anything better.  Living out in the jungle surrounded by monkeys and a whole range of other interesting creatures I had never previously encountered is something I will never forget.  I learned so much about the animals, the forest, the trees and collecting data, which is really valuable knowledge and experience and I’m sure will open so many opportunities for me.  I’ve now submitted my Masters’ thesis and am hoping to continue my work with further research in the future.

Nicki Guisneuf

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