Since 1984, National Zoo Scientists and collaborators in Brazil have been reintroducing zoo-born golden lion tamarins back into the forests of Brazil. These tamarins have primarily been introduced on to private lands. The objectives of the program are to:

  1. Increase the size of the wild GLT population
  2. Increase the genetic diversity of the wild population
  3. Expand geographic distribution of the wild population
  4. Protect additional tracts of Atlantic Coastal rainfores
  5. Contribute to the science of reintroduction
  6. Enhance programs of public education

The reintroduced golden lion tamarin (GLT) population reached 424 in this, our eighteenth year of reintroduction. This growth continues to be due to reproduction on 22 privately owned ranches surrounding the Poço das Antas Biological Reserve in the Atlantic Coastal Rainforest. There were 85 known births and newly discovered older offspring in 2001. The 424 GLTs now live in 62 groups (some of these are transitional) on about 3,300 hectares of forest. No zoo-born tamarins were released in 2001, since all of the habitat within practical commuting distance for our eight-person field team is at carrying capacity for groups. The proportion of the reintroduced population comprised by wild-borns remains at 95 percent. Survival of the wild-born offspring remains at 70%, averaged over all age classes, largely because they are more quickly self-sufficient than zoo-born reintroductees.

The reproductive success over the past six years has produced two generations of sexually mature young adults. Mean group size increased from 5.8 in 1995 to 7.5 in 1998 as a result of reproduction. But then these "baby boomers", especially the females, began to emigrate and found new reproductive groups. This resulted in social instability, group fission, and suspected emigration beyond our study area. Average group size decreased from 7.5 in 1998 to 7.0 in 1999, and has leveled off at 7.2 in 2000 and 2001.

Remarkably, the 18 captive-born reintroduced golden lion tamarins that were alive at the end of 2000 survived through 2001. These include two males born at the Skansen Zoo (K2, studbook #1817, born 1987 and reintroduced in 1988; K3, #1972, born in 1988, reintroduced in 1988), and two brothers born at the Riverbanks Zoo (CB5, #2167 and CB6, #2168, both born in 1990 and reintroduced in 1991). These four males are members of reproductive groups, although we can't confirm that they bred in 2001. K2 has lost most of his teeth, and has a scratchy, barely audible long call. Other captive-born survivors include a male from Skansen (ST3, #2342, born in 1991, reintroduced in 1992) and a female from the Emmen Zoo (E6, #2323, born in 1991, reintroduced in 1992). E6 gave birth to and raised twins, apparently sired by ST3, during the year. All captive-born members of Zoo Atlanta's Olympia Group, released in 1996, and Brookfield Zoo's Grupo do Jorge, released in 2000, also survive. Both groups have reproduced, and emigrating offspring have founded several new groups.

However, captive-borns are a small part of the reintroduced population, which will continue to grow through reproduction. The growth is cost-effective, since GLTs born in the wild do not require daily feeding and management. Further reintroductions of captive-borns may be necessary to provide genetic diversity in the reintroduced population, improve the genetic and demographic status of the captive population, promote conservation education, and maintain support for the program by the zoo community. At present there is no suitable vacant habitat within practical commuting distance of our eight-person field team. Thus, any future reintroductions of captive-borns would require translocation of self-sufficient groups to more remote areas, to create closer habitat vacancies for the new reintroductees which require intense post-release management. No new reintroductions are planned in 2002, but Paula Procopio, Technical Director of the Associação Mico Leão Dourado, has received a grant for metapopulation planning for GLTs, and will convene a workshop in 2002/2003 to set terms of reference and help define the scientific issues, including the need for further reintroduction of captive-borns.

In August 2001, we completed the final version of our analysis showing that free-ranging experience for GLTs in zoos in North America and Europe confers no significant advantage in survival over being reintroduced directly from zoo cages, even without any training whatsoever. In 2002, Smithsonian Institution Press published Lion Tamarins: Biology and Conservation, edited by Devra Kleiman and Anthony Rylands. This finding is already stimulating thinking about the necessity of pre-release preparation for reintroduction in general.

New research includes study of differences in behavior between the first and second generation offspring born in the wild to zoo-born reintroductees, the association between the reintroduced golden lion tamarin population and the introduced population of non-native common marmosets, and the level of stress associated with capture and processing of reintroduced golden lion tamarins (see below). We will also examine more than 15 years of biometric data taken during processing of reintroduced golden lion tamarins to search for correlates (e.g. body weight, canine length) of survival.

Another major new initiative will involve collaboration with a project to establish forestry corridors between the Poço das Antas Biological Reserve, with its population of wild golden lion tamarins, and the Fazenda do Rio Vermelho, with its population of reintroduced tamarins. This project, coordinated by Rosan Fernandes, involves planting 50,000 native trees on about 20 hectares of farmland to connect the two sites and forest fragments between them, over a 30-kilometer corridor. The route has been chosen on the basis of GIS mapping and analysis of forest type. This forest corridor will provide additional habitat for many species, and the potential for genetic admixture between the two largest wild subpopulations of golden lion tamarins. The reintroduction observers will help monitor the movement and behavior of golden lion tamarins as they begin to use the corridor.


  1. Increase the size of the wild golden lion tamarin (GLT) population: The 424 tamarins in the reintroduced population represent more than one-third of the approximately 1100 GLTs living at liberty in the Atlantic Coastal Forest. Reintroduction of captive-born GLTs, as well as translocation of wild GLT groups living in small jeopardized forest fragments to a newly established federal biological reserve, and increases in the wild Poço das Antas population due to enhanced protection, education and habitat recovery, have all led to steady population growth over nearly two decades. (However the Poço das Antas wild population decreased between 1998 and 2000, for reasons not yet completely understood).
  2. Increase the genetic diversity of the wild population: Although we continue to restrict reproduction between the native and reintroduced populations (to protect the native population), there have been several known cases of interbreeding. Some descendants of reintroduced and translocated GLTs in the Poco das Antas Reserve have crossed into wild groups. The growing reintroduced population is a reserve of "zoo" genetic material, some of which originated from wild populations distinct from Poço das Antas. This material can readily be injected into either the native population, or the translocated population being established on Fazenda Uniao. We will join a meta-population planning effort to decide when and where to interbreed these populations.
  3. Expand geographic distribution of the wild population: Reintroduced GLTs currently live on 22 private ranches in four municipalities around Poço das Antas. Further expansion will be governed by funding to add and equip additional observers to manage additional GLT groups, as well as occupation of new forest corridors.
  4. Protect additional tracts of Atlantic Coastal rainforest: The 22 ranches currently with reintroduced tamarins represent about 3300 hectares of forest set aside for them (and less glamorous ecosystem components) by private owners. This is about 30 percent of habitat protected for GLTs. In a separate experimental program, native trees have been planted to provide mini-corridors between ranches, and reintroduced GLTs were seen moving through these corridors in 2001. A major new initiative will involve our collaboration with a project to establish forestry corridors between the Poço das Antas Biological Reserve, with its population of wild golden lion tamarins, and the Fazenda do Rio Vermelho, with its population of reintroduced tamarins (see Summary, above).
  5. Contribute to the science of reintroduction: We have detailed in previous reports some of our significant findings: identification of feeding, locomotion and orientation as major deficiencies of reintroduced zoo-born tamarins; documentation of theft and vandalism by humans as the major cause of loss (see below); demonstration of an inverse correlation between age at release and post-release survival and the related conclusion that family groups are the best unit for reintroduction (see below); and development of a combination of pre- and post-release training as the most cost-effective method of reintroduction for this species. We have also published loss rates of reintroduced GLTs and their wild-born descendants, an analysis of the causes of loss, an analysis of the financial costs of reintroduction, and comparisons of this program to other successful mammal reintroductions. We have documented that the diaphragmatic thinning common in zoo-living GLTs is also present in wild GLTs, but is less severe and less frequent. We are now looking at its relationship to reintroduction success. We are also assessing the value of individual biographical histories and behavior profiles as predictors of post-release success. Our history has allowed us to speak authoritatively on animal welfare issues as they relate to reintroduction. But our most recent results, that free-ranging experience confers no post-reintroduction survival advantage, and that GLTs born in the wild to reintroduced parents have significantly higher survival, promise to profoundly impact the general science of reintroduction (Beck, Castro, Stoinski and Ballou, in press). Stoinski's doctoral research pinpointed several differences in the foraging and locomotor behavior of zoo-born reintroduced tamarins and their born-wild offspring that may explain the difference in survival. She also found that reintroduced adults and juveniles show changes in locomotor and foraging behavior over the first two years, but that juveniles adapt more quickly. Reintroduced GLTs that survive less than six months use small diameter branches significantly less than those that survive more than six months (Stoinski, 2000; Stoinski and Beck, in prep).
  6. Enhance programs of public education: Reintroduction continues to be an effective communication vehicle with influential local Brazilian landowners; citizens, political leaders and teachers in the four municipalities in which we work; and national and international media. The Reintroduction Field Coordinator and the Education staff frequently visit ranch owners in the search for new participating ranches, and there is an annual meeting for the owners of the ranches and their families. In October 2001, the Associação Mico Leão Dourado hosted all of the owners and their families of ranches participating in the reintroduction program, and presented each with a large sign marking the collaboration that can be (and has been) posted at the entrance gate. Our daily travels and general presence, including purchasing fuel and other supplies, provide a familiar and compelling local presence for conservation, which of course is reinforced by the local economic impact of our payroll and purchases. There is a light but steady ecotourism visitation; reintroduced GLTs provide the only practical opportunity for tourists to see GLTs. The GLT reintroduction has been featured on several internationally aired television documentaries in past ten years.

The goals and methods of the golden lion tamarin reintroduction have been approved by the Instituto Brasileiro do Meio Ambiente e dos Recursos Natureis (IBAMA), license number 285-2001-DIFAS, and the associated scientific research is approved by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), portaria 77.

Recent Publications
Castro, M.I., Beck, B.B., Kleiman, D.G., Ruiz-Miranda, C.R., Rosenberger, A.L. 1998. Environmental enrichment in a reintroduction program for golden lion tamarins (Leontopithecus rosalia). In D.J. Sheperdson, J.D. Mellen, M. Hutchins, (eds), Second Nature: Environmental Enrichment for Captive Animals (Washington, D.C., Smithsonian Institution Press). Pp 97-128.

Ruiz-Miranda, C.R., Kleiman, D.G., Dietz, J.M., Moraes, E., Grativol, A.D., Baker, A.J., Beck, B.B. 1999. Food transfers in wild and reintroduced golden lion tamarins, Leontopithecus rosalia. American Journal of Primatology, 48:305-320.

Menzel, C. R. and Beck, B.B. 2000. Homing and detour behavior in golden lion tamarin social groups. In S. Boinski and P. Garber (eds), On the Move; How and Why Animals Travel in Groups (Chicago, University of Chicago Press). Pp 299-326.

Rodrigues de Oliveira, Claudia. 2000. Comportamento de Brincadeira do Mico Leao Dourado (Leontopithecus rosalia Linnaeus 1766) Selvagem e Reintroduzido: Organizacao, Efeitos de Cativeiro, e a Hypotese de Minimizacao dos Custos. Masters Thesis, Department of Psychobiology, Universidade de Sao Paulo.

Stoinski, T.S. 2000. Behavioral differences between captive-born, reintroduced golden lion tamarins (Leontopithecus rosalia rosalia) and their wild-born offspring. Georgia Institute of Technology. Unpublished Doctoral Dissertation.

Stoinski, T.S., Beck, B.B., Bloomsmith, M.A., & Maple, T.L. 2000. Behavior differences between the first and second-generation descendents of captive-born, reintroduced golden lion tamarins. Annual Meeting of the Animal Behavior Society, Atlanta, Georgia, June.

Viera Faria, Guilherme. 2000. Diferencas nos Comportamentos de Forrageio Extractivo entre Mico Leoes Dourados (Leontopithecus rosalia Linnaeus 1766) Nascidos em Cativeiro Reintroduzidos e Sua Prole Nascida na Mata. Senior Undergraduate Thesis; Universidade Estadual do Norte Fluminense.

Ruiz-Miranda, C.R., Affonso, A.G., Martins, A. and Beck, B. 2000. Distribucão no Sagui (Callithrix jacchus) nas areas de ocorrencia do Mico Leão Dourado (Leontopithecus rosalia) no Estado do Rio de Janeiro. Neotropical Primates 8(3): 98-101.

Stoinski, T.S. & Beck, B.B. 2001. Behavioral differences between captive-born golden lion tamarins and their wild-born offspring. Annual Meeting of the International Society of Primatologists, Adelaide, Australia, 7-12 January.

Stoinski, T.S. and Beck, B.B. 2001. Spontaneous tool use in captive, free-ranging golden lion tamarins. Primates 42(4): 319-326.

Beck, B.B. 2001. A vision for reintroduction. AZA Communique, September, pp 20-21.

Beck, B.B., Castro, M.I., Stoinski, T.S., Ballou, J. In press. The effects of pre-release environments on survivorship in golden lion tamarins. In The Lion Tamarins: Twenty- Five Years of Research and Conservation, D.G. Kleiman and A. Rylands, eds. (Washington, D.C., Smithsonian Institution Press).

Stoinski, T. and Beck B. In prep. Behavioral change in captive-born, reintroduced golden lion tamarins (Leontopithecus rosalia rosalia).

Grant History
The Golden Lion Tamarin Reintroduction Program has received funding from numerous institutions since it began in 1983. These include:

The Frankfurt Zoological Society's Help for Threatened Wildlife Fund;
Friends of the National Zoo, the Smithsonian Institution Nelson Fund;
Smithsonian Institution Scholarly Studies Fund; and
The Wildlife Preservation Trust.

Staff of Team Reintroduction
Andreia Fonseca Martins, Field Coordinator
Nelson Barbosa dos Santos, Subcoordinator
Paulo Eduardo Santiago, Research Assistant and Field Observer
Elisama Moraes dos Santos, Research Assistant and Field Observer
Jabez Moraes dos Santos, Research Assistant and Field Observer
Arleia Fonseca Martins, Research Assistant and Field Observer
Sidnei de Mello, Research Assistant and Field Observer
Oberlan da Costa, Research Assistant and Field Observer