A first in Brazil: Black-faced lion tamarins vaccinated

Deep within Brazil’s coastal restinga area in Paraná state, a team of conservationists from the Society for Wildlife Research and Environmental Education (SPVS) embarked on a mission on a Wednesday in July. Their objective was to vaccinate the critically endangered black-faced lion tamarin, locally known as the caissara lion tamarin (Leontopithecus caissara).

Three researchers cautiously navigated a trail, each carrying a small, darkly clothed cage containing a tamarin safely captured from the treetops. The tamarins — two males and one female — were swiftly transferred to a tent in a forest clearing, where a team of veterinarians awaited their arrival.

The black-faced lion tamarin is one of four lion tamarin species endemic to the Atlantic Forest and ranks among the world's most threatened primates. First discovered and described by scientists in 1990, its wild population was estimated at a mere 392 individuals in a 2011 study. The vast majority of these tamarins reside in coastal restinga areas along the São Paulo-Paraná state border.

The species' already limited range has been further fragmented over the years due to human activities, including the construction of the Varadouro Canal — a 6-kilometer long, 50-meter wide artificial channel.

As the tamarins were examined and weighed, it marked a historic moment: they became the first members of their species to receive the yellow fever vaccine. With their population already critically low, this innovative vaccination effort aimed to protect one of Brazil's rarest mammals from the deadly disease.