The black lion tamarin Leontopithecus chrysopygus originally occurred
throughout a large part of the Atlantic forest in the west of the stat
e of Sao Paulo, Brazil. Today, however, it is restricted to a few isol
ated forest fragments as a result of deforestation caused by cattle ra
nching, and urban and agricultural expansion, especially in this centu
ry. One of its last strongholds is a small gallery forest at Lencois P
aulista in the west-central part of the state. The authors report on a
long-term study of this small and isolated population, aimed particul
arly at providing a basis for the intensive management and conservatio
n of the species and its habitat.