Tracking what's alive on Earth and what affects it.
Humans, now
Counted back up
Golden lion tamarin
about4,800
Estimate, no range
2023
Leontopithecus rosalia
Atlantic Forest, São João River Basin, Rio de Janeiro state, Brazil
Counted 2023, by the Associação Mico-Leão-Dourado.
The latest figure for the golden lion tamarin is about 4,800, an estimate published with no range, from the 2023 census by the Associação Mico-Leão-Dourado.
In 1971, an early estimate put wild tamarins below 400. The Associação Mico-Leão-Dourado's 2023 census gives about 4,800.
Once fewer than 400 (1971, an early estimate) and now about 4,800, so it is listed as counted back up.
How it was counted
The number comes from a census the Associação Mico-Leão-Dourado ran in 2023 across the São João River Basin. It counts animals and is published as an estimate with no range, so it reads as about 4,800.
An estimate from the Associação Mico-Leão-Dourado's census, published with no range, so read it as about 4,800 animals rather than exactly that many.
Earlier figures
- Fewer than 400 in 1971, an estimate: the dated low. Source: Dietz, Hankerson, Alexandre, Henry, Martins, Ferraz and Ruiz-Miranda, Scientific Reports (2019), DOI 10.1038/s41598-019-49199-6; Dietz, Henry, Martins, Ferraz and Ruiz-Miranda list Associação Mico-Leão-Dourado (AMLD) as affiliation.
What moves it
The Associação Mico-Leão-Dourado names fragmented forest as its biggest challenge. Its report also names yellow fever, which killed many primates in the last outbreak, and wildlife trafficking.
- forest fragmentation. Source: Associação Mico-Leão-Dourado (AMLD), Annual Report 2025.
- yellow fever. Source: Associação Mico-Leão-Dourado (AMLD), Annual Report 2025.
- wildlife trafficking. Source: Associação Mico-Leão-Dourado (AMLD), Annual Report 2025.
Who is helping
The Associação Mico-Leão-Dourado strengthened the Jennifer Mickelberg forest corridor and, with ICMBio, created a federal private reserve (an RPPN). With Fiocruz, ICMBio/CPB, the Rio de Janeiro Primatology Center (CPRJ) and the North Fluminense State University (UENF), it vaccinates wild tamarins against yellow fever. With UENF, it returned tamarins seized from traffickers to the wild after rehabilitation at CPRJ.
The next count
No date is known for the next census. The timing is irregular (censuses several years apart).
Sources
- Associação Mico-Leão-Dourado (AMLD), Annual Report 2025 Last checked 12 November 2026.
- Dietz, Hankerson, Alexandre, Henry, Martins, Ferraz and Ruiz-Miranda, Scientific Reports (2019), DOI 10.1038/s41598-019-49199-6; Dietz, Henry, Martins, Ferraz and Ruiz-Miranda list Associação Mico-Leão-Dourado (AMLD) as affiliation Last checked 12 November 2026.
What changed
- 12 November 2026 Added to Live Species, on the wall, counted back up: About 4,800 (Estimate, no range, 2023).
Next on the wall
The letter
The letter comes once a month, on the first Thursday. It gives what changed on Live Species, one animal up close and the humans figure for contrast.