Trapping Tamarins

The main emphasis of Mini’s dissertation is on genetic chimerism in tamarins. Tamarins are unique in a bunch of ways, but one of them is that tamarins habitually have twins. Due to a quirk of the placenta, the blood vessels that supply the twins overlap and cross, and on occasion, bits of stem cells transfer between individuals. Depending on what the cells end up becoming, this can have really interesting consequences. A baby tamarin may have its sibling’s liver cells, or some of its fur, or – in the most exciting cases – its gametes. This means that an animal has the potential to give birth to its sibling’s child. Mini wants to know if this has behavioral effects, especially relating to parenting. The most important thing, then, is to know the genetics of a whole bunch of different bits – hair, nails, blood, sperm, etc. Not the easiest thing to collect in the wild, so one of the things we’ve been doing is attempting to trap groups. This serves the dual purpose of allowing us to put indentifying marks on the monkeys – a radio collar, beaded necklaces, dyed tails – while collecting genetic information.

On March 5, the day’s plan was to trap Jean 4 and FC. We have wire platforms and traps (basically compartments with swinging doors that we can tie closed) dispersed around the jungle in places we know groups hang out, with bananas sitting on them. Jean 4 is a group that we’ve been following pretty consistently, but have yet to trap, and FC is our marked group. We still needed some genetic information from RC, the presumed mother, and the two twins who were too young to be anesthetized when they were initially trapped. Unfortunately, when we went out to trap Jean 4, we realized that what we thought was tamarins eating bananas from traps had actually been capuchin monkeys. So we called that pretty quickly. Karina, Emma and I went out to follow FC for the rest of the day when (surprise) it began to pour! FC went and hid in a bramble while the three of us went to wait out the rain in the lab.

Mini and Gideon were heading back to the lab at the same time (they were much dryer than us because they took a tarp out with them!). They were really excited to hear that FC was so close, so we put up a trap that had been taken down earlier. Emma and Karina stayed with FC, who were still in their bramble, while the rest of us set up the trap. Eventually, all of FC moved around the trap. RC and GPG grabbed the bananas off the top of the trap and the doors while everyone else was swarming around trying to decide if the metal was dangerous, if the bananas were worth chancing the metal, and (once they did), how the heck to get back out! RC was the first monkey we trapped, followed by Twin 2, GBR, and GPG. They get really irritated when they’re trapped, and try really hard to get out – squeaking, struggling, pushing against the mesh, etc. Twin 1 was the only saddleback out of the trap when a group of emps came and investigated the trap. There were about five emps swarming around and in the trap – at least one emp went in the empty compartment and ate bananas, and several emps scent marked and climbed around the top of the trap, especially around GPG. She was not impressed.

Twin 1 was scared off of the trap by the emps and spent the next 20 minutes or so climbing around the back of the trap, between the bottom of the trap and the platform, on trees around the trap, and up on top of it. Gideon approached in the hopes that he could catch Twin 1 if he wouldn’t get in the trap, and also to scare away the emps. The strings of all the compartments except for GBR’s were tied to a tree, and we were focused on getting 1 in a compartment when GPG broke through the mesh of her compartment and escaped. After that happened e decided then to let GBR go and take RC and Twin 2 in to be processed, while GPG, GBR, and Twin 1 stayed out, as it was late enough that we’d need to keep the trapped animals overnight.
Karina and Emma followed the rest of FC to their sleeping site while Mini, Gideon and I prepped the lab for processing. After a little while, we decided to go ahead and start processing Twin 2. I started out just taking notes – noting the weather, times of injection, what samples were being taken, stuff like that. But once RC also was given Ketamine and Karina and Emma came in, I just held on to Twin 2 and started taking data and keeping her cool. We had a wide variety of things to get – fecal samples, cheek swabs, blood samples, stuff like that. We also took a dental cast (baby tamarins have REALLY TINY teeth!) and tried to bleach her tail to make her more distinct from Twin 1. After her bleach had been in for about 30 minutes, I got to give her a bath to wash the excess bleach out. Soaking wet baby tamarins are pretty adorable.

After we finished processing both RC and Twin 2, we put them in the recovery cage. They were definitely groggy, and sort of wobbled around for a little while. We put banana and water in and covered the cage up. When Mini checked on them later that night, Twin 2 was asleep on top of RC. The trapping experience was really cool – it gave me a lot of perspective on the monkeys. They look so big when you’re watching them. Well, that’s a lie. But they definitely look larger than when you’re holding them in your hand. Twin 2 literally fit in the palm of my hand. Her hands were clasped around my finger and she was NOT letting go. 160 grams of monkey is not a whole lot.

Hopefully we'll be trapping more in the future - the problem has been getting them to go IN the trap. We use playbacks of saddleback calls to get them to come to the traps, but they get so caught up trying to find who was calling that they never actually sit down and eat bananas. Mini and Gideon have an agreement with a rehabilitation center to borrow a baby tamarin rescued from the pet trade. He's going to be staying with us for the next couple of months and when we trap, we'll put him out to call to the other monkeys so that they'll go in to investigate. He's set to come next week, so hopefully I'll have lots more trapping stories to tell!!