I was placed on String 9, and that alone was challenge #1. I was both thrilled and hesitant when I got my paperwork during the orientation. It said something like "String 9 has the most taxonomically diverse species of all the strings" (Yay!) "but is one of the more physically demanding strings" (Crap!). I was responsible for a plethora of birds, zebras, and various reptiles...and the Cotton Top Tamarins! They have mohawks.
Halfway through the internship I realized that due to the insane amount of work that keepers are responsible for, I had all but almost forgotten about my project. I thought about the animals I was working with and was stumped. How do I get birds or snakes or pancake tortoises, or an ancient White-throated monitor to interact with enrichment that doesn't contain food stuffs? Stacy, my supervising keeper, asked if I would be interested in observing the tamarins. They had once been a happy group of 7 but one of the males became ill and succumbed to a contagious respiratory infection and soon after, another male in the group had begun to show symptoms. Due to the zoonotic nature of the disease it was imperitive that the ill monkey be removed and quarantined to protect the other animals at the facility, the keepers and the zoo guests. Removing a tamarin from its group, however, would sacrifice the sensitive heirarchy but it had to be done. Once well, and after its extensive hospital quarantine, the zoo staff attempted to place the monkey back into the group. Unfortunately two females fought to the point where they had to be removed from the group to regain a sense of peace. The mom and daughter pair, Mama and Shirley, were taken to another building where they would be completely segregated from the other group. This is where my job began. Still unhappy, the two constantly went after each other and with the keepers busy schedules it became very difficult for them to observe and fix problems. I found my project. What triggers Mama and Shirley to fight and how can we change these behaviors?
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| Photo credit Oaklandzoo22 "Cotton - Top Tamarin" 12/7/2006 |
BACKGROUND
Cotton top tamarins (Sanguinus Oedipus) are endangered, arboreal, new world monkeys that live the tropical rainforests of South America, specifically in the northernmost parts of Colombia and Venezuela. Cotton topped tamarins breed monogamously and live in groups ranging from one to fifteen individuals though most groups consist of up to nine individuals. Each group consists of a dominant male/female pair and their offspring of the year and a few subordinates of both sexes that tend to freely migrate in and out of the group. All group members cooperate and take turns caring for the young of the group.
Using a sophisticated grammar of birdlike whistles and chirping sounds tamarins are able to express emotions including fear, playfulness, warnings and calls to young. Another form of communication is tonguing which is when a tamarin rapidly moves its tongue out of its mouth across the lips. Facial expressions include a threat face to which a tamarin will lower its forehead until a bulge that almost covers the eyes forms. Lips are pushed forward and head and neck crests are erected.
Tamarins have a sensitive hierarchy in which the breeding male and female are dominant over the younger animals. Cotton top tamarins are relatively peaceful towards their own group members but intruders are usually met with a large threat displays with minimal physical violence. To mark their territory these tamarins will scent mark by rubbing their anogenital region on tree branches. Within the group, the breeding female can also be aggressive towards younger females resulting in reproductive repression of the subordinate females and higher access to food items. Fighting within groups resulting in the removal of individuals is not unheard of for cotton top tamarins. Typically, in family groups aggression tends to be directed toward offspring rather than breeding individuals and aggressors are usually the same-sex parent or siblings. The majority of fighting between siblings is between the eldest male and his siblings. Most of the aggression between individuals begins slowly, escalates rapidly and becomes unpredictable. As group size increases the likelihood that aggression between the oldest male siblings will increase and in response the subordinate siblings will emit submissive vocalizations and avoid contact with the dominant sibling. It is recommended that the aggressor be removed from the group when the victim is seen staying lower than normal in the exhibit. Similarly, aggression between father and a male offspring can be vicious and the aggressor should be removed from the exhibit. This is usually the case when a change in the environment has been made like moving animals to a new exhibit. Finally, aggression between females can be rare but, like paternal/male offspring fighting, is caused by a disruption in the living environment. In this case, daughters challenge mothers by mounting, harassing and displacing but the mother will defend her placement in the hierarchy unless she is old or impaired. Unlike the other cases of aggression, the submissive female should not be removed unless the mother is becoming aggressive. In captive situations it is more common that submissive females will be evicted than submissive males.
OBSERVATIONS
For these observations I used scan sampling in 15 minute observation times with 30 second sample intervals. Observations were conducted primarily on Sundays and Mondays with an occasional Wednesday, over a period of 8 weeks and at random times during the day between the hours of 9 am and 4:30 pm. The ongoing goals are to watch enclosure usage and look for fighting between the tamarins and to try to better understand what could be inciting the fights. I have also included some data from another observer on the Behavioral Observation Team who used ad-libitum sampling. I called the front cage “enclosure F” based on the fact that the handle to shift gate “F” is attached to this enclosure. Likewise, the next enclosure back I called “enclosure E” because the handle to shift gate “E” attaches to this enclosure. Also, later in my observations, the enclosures were separated vertically into four different levels. Level 1 is the lowest level to the floor and Level 4 is the highest, closest to the ceiling. I did this to help me to determine which vertical position in the enclosures each tamarin preferred to be in.
2/20/11 – 2:45 PM. GOAL: watch for fighting and observe enclosure usage
On this day, both Mama and Shirley had access to both enclosures; however both tamarins seemed very preoccupied by my presence and did not move around in their enclosure much. They stayed primarily in a basket in enclosure E and no fighting was noted.
2/21/11 – 12:55 PM. GOAL: same as 2/20/11
Today both tamarins seemed a little more active however both spent the majority of their time in enclosure E. With this data set it is difficult to determine whether the tamarins were spending their stationary time in a social context. It would have been helpful if I had made notes of this behavior.
2/27/11 – 9:25 AM. GOAL: determine why Shirley was spending significant amount of time on the floor of her enclosure.
Prior to this day, Mama and Shirley fought and were physically and visually separated. Mama was put into enclosure E and Shirley into enclosure F. A sheet was hung in enclosure F to visually separate them and it is this day that I started observing the level of enclosure usage.
The sheet was hung too loosely and Shirley was able to maneuver her way behind it to antagonize Mama. Shirley was so focused on figuring out how to get to Mama that she spent a significant amount of my observation time on the floor, looking up at Mama behind the sheet. I was able to record three separate incidences where Shirley was on the floor and two separate incidences where she was able to interact with Mama. In fact, she spent the majority of her time at the 1-2 levels of the enclosure. There was a significant amount of frantic alarm calling but because I did not have access to the hallway to see Mama’s behavior, it was impossible to tell who was initiating the alarm calling or if was responding to Shirley’s actions.
9:45 AM. GOAL: same as previous observation
This observation session is a continuation of the prior session. I was able to record Shirley on the floor 3 times with two times interacting with Mama and the frantic alarm calling continued.
4:10 PM. Goal: same as previous two observations
At this time I have observation access to both enclosures. Mama observed scent marking on two occasions and favored ambulating over stationary behaviors. She stayed higher in the enclosure at the 3-4 level and though she took interest in Shirley’s behavior it did not seem aggressive in nature. Shirley also favored ambulating but stayed lower in her enclosure at a 2-3 level and was much more frantic and aggressive in nature.
2/28/11 - 11:22 AM. GOAL: continue observations of enclosure usage
The sheet was replaced with cardboard that was zip-tied to the enclosure wall separating Mama and Shirley and was placed on Shirley’s side.
On this day, Mama preferred to be stationary at a high level of her enclosure. She stayed around the 3-4 level area. Shirley seemed to have an equal proportion of ambulating and stationary behavior. She was still pretty frantic but without visual access she stayed higher in her enclosure. The data shows her at primarily levels 3-4 but the majority of her time was spent using her hands and teeth to tear down the cardboard while engaging in a significant amount of alarm calling.
3/7/11 - 11:45 AM. GOAL: to observe the three remaining tamarins in the rainforest building. One tamarin was spotted to be segregated from the others on prior occasions.
I did see that one of the tamarins was comfortably segregated from the other two. All three began alarm calling and continued for about 5 minutes after which all three calmed down and seemed very relaxed. They engaged in behaviors like stretching, napping, eating and social chase behavior. All three stayed in the same enclosure though there were times that they occasionally seemed interested in leaving to the exhibit through the shift gate.
1:00 PM. GOAL: same as prior observation
All three tamarins were again very relaxed. I was able to record 3 separate incidences of social behavior; two were with all three tamarins. Also, I was able to record 4 separate incidences of the tamarins using enrichment in the enclosure.
3/21/11 - 2:00 PM. GOAL: watch for fighting and their triggers
Both tamarins are now in enclosure E. They both fought and scratched each other between the enclosures. As a result they were physically and visually separated for 1 week. They were then removed from the building for about 24 hours while both enclosures were thoroughly cleaned with diluted bleach and rinsed with water in hopes that all scent marking areas became a neutral scent. New enrichment was hung and both Mama and Shirley were placed back in enclosure E which unfortunately resulted in some fighting.
Though the tamarins fought again, they were left together in the same enclosure. At the time of observation there was minimal alarm calling and both were seen sharing enrichment and social behavior despite the fact that fighting sounds were noted by the keepers on 3/20/11. The tamarins also seemed
fairly active, social and utilized different levels of the enclosure. I did not make note, however, of which tamarin was spending time in which level of the enclosure.
3/24/11 - 1:40 PM. Observer Ted G.
The observer was watching for aggressive behavior. One of the tamarins was seen screaming in the others ear as a dominant behavior. Mama was seen on several occasions scent marking and being dominating around their food and Shirley was seen submissively foraging for food on the lower levels of the enclosure. At one point Shirley found a bit of food and went to a higher location to eat to which Mama responded by screaming at Shirley, though later in his observations, Ted notes that both Mama and Shirley shared a bowl of food without incident.
3/27/11- 3:20 PM. GOAL: observe for aggressive behavior.
Both tamarins were started on Depo-provera birth control shots and anti-anxiety medication. The thoughts were that it is possible that one or both were coming into season and through pheromone and hormonal changes fights were occurring. The anti-anxiety medication will hopefully work to calm the tamarins to the point where they can successfully coexist without fighting.
It is during this observation session that I started paying more attention to whether the times that the tamarins were sitting stationary were spent socially. The majority of their time was spent at the 2-3 level areas of the enclosure. 4 incidences of social behavior were noted as well as a nice combination stationary and ambulatory behavior. It is probably too early to tell if the medications are working.
4/3/11 - 1:40 PM. GOAL: watch for aggressive behavior
Tamarins were noted to be face-to-face and raised up on haunches with hands in the air. It just so happened that at the same time keeper Lisa walked into the hallway and Shirley jumped over mama and walked away. This occurred approximately 10 minutes after both tamarins were given access to their new enclosure. It is uncertain if this behavior is a typical pre-physical altercation behavior because we have yet to see how they are interacting prior to the onset of the fight. In this case there was no food of any sort in the enclosure and I did not see any indicative behavior that would cause alarm. It has been speculated however that the reason they did not continue to fight was because of the anti-anxiety medication that they both had started ~1 week prior. However it is possible that the behavior could have turned into a fight but was interrupted by Lisa’s coincidental presence.
4/5/11 Both tamarins were seen spending a significant amount of time on the floor of their enclosure.
4/6/11 – 4:00 pm GOAL: watch for aggressive behavior; sitting on floor of enclosure
Mama alarm called as she watched Jason leave the building. She was sitting in the upper most part of the enclosure in the front staring down the hallway, while Shirley sat a little lower in the back of the enclosure. Once Shirley heard the door close she too started to alarm call. Upon hearing Shirley’s alarm calling, Mama turned and ran to her and tackled her. There was no screaming or fighting, just the initial tackle and it was over as soon as it started. Shirley was crouched down as Mama jumped on her determining that Shirley is the submissive in the group. They both went in separate directions and were able to quickly recover and continue social behavior. After this altercation I was curious to see who initiated alarm calling and what set them off. During my observations, it was only Mama who alarm called 3-4 times. The initial alarm call was when Jason had walked out of the building, then once when the Hadada Ibis’s were calling, and once for no known reason. I was also watching for food aggression however, both tamarins were able to sit near the food trays peacefully, though Mama took the dominant location high in the cage to eat while Shirley stayed down lower at the food tray. It’s also interesting to note that both tamarins scavenged for bread in the same piece of enrichment without altercation. Jason has noted that during training and hand feeding sessions it is hard to determine who is higher in the hierarchy. I wonder if this is because they see the keepers as a dominant figure because it is they who control the food. If so, will the keepers have the ability to establish a hierarchy that will stick with the tamarins even when the keepers are not around?
4/10/11 - 9:45 am, ~10:30 am GOAL: observe for aggressive behavior
Tamarins fought last night or early this morning. Shirley has 1-2 lacerations on the top of her head and above her right eye. Morning observations were unremarkable and both tamarins were sharing the enclosure equally. Later in the morning I was making diets and noticed that Mama was sitting closer than normal to Shirley with face up to the side of Shirley’s head. Worried that she was going to scream in her ear again, I took a closer look and realized that Mama was cleaning Shirley’s wounds while making soft chirping noises. This went on for at least five minutes in full view but they soon both went out of sight and quietly sat in a basket. No other fighting was seen during the day.
4/11/11 -
As I was cleaning the reptile building I noticed the Mama and Shirley sitting closer together than normal and as I watched them more Mama began to scream in Shirley’s ear. I interrupted them and checked on them a few minutes later. At this point Mama was grooming Shirley and a few minutes later I saw Shirley grooming Mama. They stopped when they saw me watching them.
CONCLUSIONS
The best conclusion that I can make as a result of my observations is that I truly don't understand the social structure of tamarins. Every attempt we made to ease the anxiety of the group was thwarted by the clever brains of these little monkeys. Like children, maybe they're fighting (literally) for attention? That is, if I'm allowed to anthropomorphize these little guys.
BIBLIOGRAPHY
Csew.com. “Cotton Top Tamarin SSP Webpage.” http://www.csew.com/cottontop/SSP/Enghome.htm Accessed 4/13/11
Cawthon Lang KA. 2005 May 18. Primate Factsheets: Cotton-top tamarin (Saguinus oedipus) Behavior . <http://pin.primate.wisc.edu/factsheets/entry/cotton-top_tamarin/behav>. Accessed 2011 April 14.
Animalinfo.org “Animal Info – Cotton Top Tamarins.” http://www.animalinfo.org/species/primate/saguoedi.htm. Accessed 4/13/11
Rollinghillswildlife.com. “Cotton Topped Tamarin.” http://www.rollinghillswildlife.com/animals/t/tamarincottontop/tamarin_cotton-top.pdf. Accessed 4/13/11
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