Seven more howler monkeys are released into Tijuca National Park

A group of seven red-headed howler monkeys (Alouatta guariba) were released this Tuesday (2) in the Tijuca National Park, in Rio de Janeiro. This is the second reintroduction of the species at the site, part of a project started in 2015.

Red-headed howler monkeys were native to the park, a federal conservation area and one of the two large Atlantic Forest regions in the city of Rio de Janeiro, but they were extinct there around 200 years ago.

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In 2015, a pair of red-headed howler monkeys were released there. They reproduced and gave rise to the current population, which has eight animals. The new group, which came from the Rio de Janeiro Primatology Center (CPRJ), is made up of one male and six females, aged between eight months and 15 years.

The expectation is that they will interact with the family that already lives in the park and can guarantee the genetic diversity of the species there.

“This new group, which is now being reintroduced, practically doubles the genetic heritage of this population, so the chances of the population maintaining and growing are much greater”, says veterinarian Silvia Bahadian Moreira, from CPRJ, an organization linked to the State Institute of Environment (Inea).

According to biologist Marcelo Rheingantz, from the Refauna project and researcher at the Federal University of Rio de Janeiro (UFRJ), the howler monkey reintroduction project had to be interrupted in 2017, due to the yellow fever epidemic among primates.

In 2020, the howler monkeys were already vaccinated against yellow fever and ready for release, but the Covid-19 pandemic postponed the project once again. “Last year, we started the whole process again, because the three animals [iniciais] they became seven, so we had to vaccinate the four new ones”, says Rheingantz.

According to the biologist, the reintroduction of new animals is planned. The goal is for the howler monkey population in the forest to reach 100. “This is essential for us to have an established population in the long term, that is, with at least ten groups of howler monkeys roaming the forest”, says Rheingantz, highlighting that Howler monkeys are one of the 25 most threatened primates in the world.

The primate releases are part of the Refauna project, started in 2009, with the aim of expanding the population of the Tijuca forest. In addition to howler monkeys, red agoutis (Dasyprocta leporina), tinga tortoises (Chelonoidis denticulatus) and ironbirds (Saltator similis).

“The Tijuca forest is wonderful, but poor in animals. Our idea is to rebuild the fauna and, with that, the functioning of the ecosystem, because we are also going to rebuild the ecological interactions of which these animals are part, such as the dispersal of tree seeds and pollination”, explains Fernando Fernandez, researcher at UFRJ and CEO of the non-governmental organization Refauna, which runs the project.