MODEL OF THE MONTH

Exploring social cognition with marmosets by Dustin M. Graham The ability to raise marmosets in the lab under rich social condi- SCIENTIFIC NAME tions, combined with their innate prosocial behaviors, enables sci- Callithrix jacchus entists to use marmosets as models of social communication and 4 TAXONOMY behavior . Recent work with marmosets demonstrated that this PHYLUM: Chordata species shares several similarities of social behavior and language CLASS: Mammalia development with humans, despite their relatively wide evolution- ary distance. Marmosets exhibit prosocial behaviors, pair-bond with ORDER: Primates mates and engage in cooperative raising of young1,4. Cooperative FAMILY: Callitrichidae breeding is a particularly rare trait among primates, making humans and marmosets potentially well suited for comparative studies of social behavior. Additionally, marmoset infants rely on General description parental interaction to develop vocalizations, which is The common marmoset is a New World mon- uncommon to most primates but a shared feature key originating from the northeastern coast of human language development4. The brain of Brazil1. Compared with other common structure of marmosets is also similar to primate models, marmosets are very that of other primates, including humans4. small, reaching approximately 17 cm in Taking into consideration recent develop- length and 250 grams in weight at adult- ments in genetics and miniaturized brain- hood1. They have a long tail relative to recording tools, marmosets are poised their body length and a distinct multi- to become an extremely valuable model color pelage of brown, grey and yellow. for understanding the neural basis of Unlike other primates, marmosets tend social cognition and language develop- to have sharp claw-like nails, which are ment. Although novel technologies, such

Nature America, Inc. All rights reserved. America, Inc. © 201 6 Nature most likely an adaptation for their arbo- as brain recording techniques and trans- real, squirrel-like locomotion among tree genics, can also be applied to other non- branches, as well as their ability to hang human primates, it remains a challenge to 2

npg vertically on trees . Marmosets have sharp create behavioral paradigms with rich social incisors and specialized guts that enable structures that mimic those that accompany them to survive on diets of plant exudates human development. Marmosets, therefore, and insects when other types of food, such as will increasingly be relied upon to help bridge

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o fruit, are not available . Common marmosets r this gap in the ability of scientists to study the

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h s i l gum and resin, as well as insects. b lying complex social behaviors, which might u P

e r lead to a better understanding of neuropsychi- u t a Research résumé N / atric disorders involving social development. r a s e Owing to their small size and ease of breeding in captiv- a Overall, these small monkeys are ready to make a C ity, marmosets have become popular scientific models, and Kim big impact on social neuroscience and the myriad of they are generally robust and healthy when kept under proper complex mental disorders that affect humans. laboratory conditions1. Their small size allows them to be socially housed and provided with relatively large amounts of space and 1. Abbot, D.H., Barnett, D.K., Colman, R.J., Yamamoto, M.E. & Schultz-Darken, enriched environments that might be prohibitively difficult with N.J. Aspects of common marmoset basic biology and life history important for biomedical research. Comp. Med. 53, 339–350 (2003). larger non-human primates at most facilities. These benefits 2. Cawthon, K.C. Primate Factsheets: Pygmy marmoset (Callithrix pygmaea) have made the marmoset a popular animal model for a diversity Taxonomy, Morphology, & Ecology. Primate Info Net http://pin.primate.wisc. of fields in biomedical research, including toxicology and visual edu/factsheets/entry/pygmy_marmoset (2005). neuroscience1,3. Since the 1960s, new insights into development 3. Zuhlke, U. & Weinbauer, G. The common marmoset (Callithrix jacchus) as a model in toxicology. Toxicol. Pathol. 31, 123–127 (2003). and behavior have continued to surprise scientists and open new 4. Miller, C.T. et al. Marmosets: A neuroscientific model and human social avenues for important research1. behavior. Neuron 90, 219–233 (2016).

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