The muzzle and sometimes face are pure white, and the neck has a ruff of bright golden to creamy fur dorsally, sharply contrasting with the black crown.

The golden-mantled tamarin is an arboreal, diurnal species ranging through the understory, moving by quadrupedal walk and leap, mainly on small horizontal supports.

Leaping is the main gap-crossing mode of locomotion, though it decreases in proportion with a higher use of the upper forest layers.

Due to its small body size, limited gut volume, and rapid rate of food passage, tamarins require a diet high in nutrient quality and available energy.

At the juvenile stage (beginning at 4–7 months) 'twin fights' may occur, especially between same-sexed twins, to determine status differences.

This species is listed as Near Threatened in light of a projected future decline of around 25% over the course of three generations (18 years) due to anticipated high rates of deforestation.

The forests where L. tripartitus occurs along the Rio Yasuni in Ecuador are remote and have, to date, suffered little impact from human activities, other than small localized encampments for petroleum prospecting.

However, the occurrence of petroleum in the region, resulting in the current construction of the Pompeya-Iro highway, is reason for some concern for the future of these forests and their wildlife.