Saving the world’s smallest monkeys from extinction
After months of fieldwork in the forests of Serra Negra da Mantiqueira, in what little remains of Brazil’s Atlantic Forest, researchers believe that the endangered buffy-tufted-ear marmoset (Callithrix aurita) could one day return to this beautiful forest reserve. Supported by Tamarin Trust with generous help from the Balcombe Charitable Trust, Rodrigo Carvalho and his team from the Mountain Marmoset Conservation Programme have been carrying out habitat assessments at the Private Natural Heritage Reserve (RPPN) Chapadão da Serra Negra da Mantiqueira, to determine whether the area could support a future reintroduction programme for the marmoset.
Dom Wormell discusses future conservation actions for buffy tufted-ear marmosets in this video:
The buffy-tufted-ear marmoset is one of Brazil’s most threatened primates, found only in fragments of the Atlantic Forest — one of the world’s most endangered ecosystems. Disease outbreaks, habitat destruction, and competition from introduced marmoset species have pushed the species into serious decline across much of its range.
Although recent surveys found no surviving marmosets in the Serra Negra region, local rural landowners told researchers they had seen the animals there in years gone by.
“These reports are incredibly important,” said Rodrigo. “They suggest the species once lived here naturally, and that the forest may still be capable of supporting them.”
It is believed outbreaks of yellow fever — which devastated primate populations throughout Brazil’s Atlantic Forest in in the past and in recent years — may explain the apparent disappearance of local groups of the marmoset.
Fortunately, the forest itself appears remarkably healthy. Botanical surveys have revealed a rich diversity of plant life across the reserve, including dozens of fruiting plant species known to be important food sources for the marmosets. These findings have strengthened confidence that Serra Negra could become an important stronghold for the marmoset in the future.
In November 2025, Tamarin Trust director Dominic Wormell joined the Brazilian team in the field to assess potential release sites and discuss the practical challenges of restoring the species to the region. The work has brought together specialists from a wide range of disciplines, including biology, geography, education, communication, and environmental law. Rodrigo is now beginning discussions about what a future reintroduction would involve, including possible locations for soft-release enclosures where marmosets could gradually adapt to life back in the wild.
Serra Negra represents a chance to restore the marmoset to an intact forest area and become a functioning component, enriching the ecosystem and becoming ecologically more complete, something increasingly rare in the Atlantic Forest. Hopefully in the near future it will once again ring with the marmosets’ high-pitched calls.
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