Friday, April 20, 2012

Primate Update E-Newsletter, Vol. 4, Issue 4, Part 3


CONTINUING EDUCATION

Special Topic: Intern Mary
Social Interactions, social relationships and the social system of spider monkeys

Spider monkeys have a fission-fusion social organization dynamic in which one large cohesive group of monkeys is broken up into a variety of smaller subgroups. These subgroups come together and split apart randomly and the number of subgroups seen together at one time depends mainly on the distribution of resources in the area. It is extremely rare for the large cohesive group to be seen altogether in the same place and many individuals move between subgroups. This type of organization has several advantages as it allows individuals mating privileges, protection, and access to more resources, which in turn reduces feeding competition.

Female spider monkeys are considered to be much less social than males. They are often seen traveling on their own or in very small subgroups consisting mainly of their offspring. However, when food resources are abundant it is common for females to join larger groups. Wild female spider monkeys groom and exchange embraces with other group members far less frequently than male spider monkeys. In captivity female spiders will only exchange embraces with other females and embraces become much more frequent in the presence of a young infant.

Male spider monkeys develop strong relationships with other males in their group. They use this relationship to compete with other communities of spider monkeys and to obtain, or maintain, dominance and mating opportunities. Males tend to stick together much more than females and are almost never seen alone in the wild. This is most likely due to the fact that it is the male spider monkeys that defend the territory. They often travel the boundary of their territory and traveling together allows individuals more protection when intergroup competition should occur. 

Another difference between male and female spider monkeys is that males regularly exchange embraces and pectoral sniffs with other males. Males also show extremely little aggression towards other males within their community. These behaviors can be seen with Carlos and Montana, the spider monkeys here at Pacific Primate Sanctuary. Carlos and Montana are very friendly to each other and often share food. They demonstrate their lack of food aggression by patiently waiting to be fed while the other is already eating. Carlos and Montana also groom each other on a regular basis. The only real aggression shown between male spider monkeys in the wild is during female reproductive cycles. There are no female spider monkeys at PPS, which more than likely plays a role in the lack of aggression between Carlos and Montana.

-Campbell, Christina J. Spider Monkeys: Behavior, Ecology, and Evolution of the Genus Ateles (Cambridge Studies in Biological and Evolutionary Anthropology). UK. Cambridge University Press. 2008.


  
PPS Spider Monkeys, Carlos and Montana, Hug


Special Topic: Intern Annabel: A Study on Aging in Marmosets
Physical Changes

As primates age they go through a number of physical changes.  Their muscles weaken, and they can suffer from arthritis in their joints.  We see an example of this in Echo.  Echo is a seventeen-year-old cotton top tamarin who suffers from arthritis in her joints.  Her caretakers can know this is affecting her by carefully observing her each morning, when the arthritis tends to act up the most.  If she is stiff or in pain, we can see this by the way she moves, as well as by a shakiness in her motion.  To help with this she is given a drop of Metacam, which acts to reduce inflammation and pain, and also helps her to loosen up.  The sunshine also seems to help her, which she can easily access using her jungle walkway, which we have constructed to help her get around her enclosure easily and safely without the risk of fall and injury. 

Another common physical change in marmosets as they age is loss of fat mass. Lean mass however increases with age. Lean mass consists of all of the parts of the body that are not fat, including bones, organs, and muscle.  As a result, not a lot of weight loss is usually seen in marmosets as they age. If we do start noticing weight loss in the Sanctuary’s aging monkeys, we put those monkeys on a ‘special diet’.  This consists of their normal diet with supplementary high calorie foods such as banana, dried fruit and nuts, avocado and rice. 

Additionally, as monkeys’ age, it is common for the teeth to get worn down, or fall out.  We see this in some of the elderly monkeys living at PPS, such as Abraham and Galatea both of whom have very few teeth left. We help them by cracking all nuts, cutting hard to chew foods into smaller pieces, and providing them with more soft foods. 

We also give various vitamin supplements to help the monkeys with common problems associated with aging. Vitamin B is used to aid the metabolism and nervous system and is given to several of the elderly monkeys. Vitamin E is used to help protect the nerves, muscles, and cardiovascular system.  We sprinkle these vitamins on their food in the morning, which helps to keep our elderly population healthy and happy.

References
-Abbot DH, Barnett DK, Colman RJ, Yamamoto ME, Schultz-Darken NJ. 2003. Aspects of common marmoset basic biology and life history important for biomedical research.
-Bowdon D. M. Aging in Non Human Primates, 1979
-Tardif S, Araujo A, Arruda M, French J, Sousa M, Yamamoto M. Reproduction and Aging in marmosets and Tamarins, 2008
-Tardif S, Keith G, Mansfield, Ratnam R, Ross C, Ziegler T, The Marmoset as a Model of Aging and Age-Related Diseases, 2008





Special Topic: Intern Linda
Marmosets and Tamarins Chapter 9: Communal Infant Care in Marmosets and Tamarins: Relation to Energetics, Ecology, and Social Organization

In tamarins and marmosets, infants are carried ninety percent of the time before they reach four weeks old. After this month, however, it varies between species and their habitats. In some studies, researchers have found that infants are carried for a shorter amount of time in the wild than in captivity. As a communal group, all parents, siblings, and helpers take turns to care for the babies.
Weid’s Marmoset Father and Child at PPS

Tamarins usually carry their infants for a longer period of time than marmosets do. This is due to food resources. Since tamarin diets include foraging for insects and fruits, they must go further from their home in order to find food compared to marmosets. Marmosets, in contrast, do not need to go far because the abundance of exudates and gum from various plants grow close together. This enables infants to begin foraging on their own at an earlier age.


The energy expended by mothers for lactation is immense; therefore the mother is typically not the primary care provider. Fathers and, later, older siblings carry and care for the babies.  Marmosets and tamarins nurture and carry infants for different amounts of time, and care for the infants differently based upon their various energy expenditures, ecology, and social structure. 
-Rylands, A.B. Marmosets and Tamarins. Systematics, Behavior, and Ecology. Oxford, U.K.: Oxford University Press, 1993.

“Never, never be afraid to do what's right, especially if the well-being of a person or animal is at stake. Society's punishments are small compared to the wounds we inflict on our soul when we look the other way.”    
Martin Luther King Jr.



We hope you have enjoyed this issue of Pacific Primate Sanctuary’s E-Newsletter. Thank you for your support of our life saving work. Because of compassionate people, the Sanctuary can continue to provide a place of peace and happiness for 70 primates saved from research laboratories, animal dealers, and tourist attractions. Here they can heal, form families, and live free from exploitation.







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