One morning in 2024, Armando Schlindwein found an orange-bearded monkey on the roof of his farmhouse on the edge of the Brazilian Amazon. The monkey, a Groves' Titi, listed as "critically endangered" by the International Union for Conservation of Nature (IUCN), had ventured far from its fast-shrinking home on a hill in a small patch of forest next to Schlindwein's house. Deforestation was eating away at its limited domain. The encounter inspired Schlindwein to launch a reforestation drive to open a corridor for the monkeys to swing tree-by-tree back into the rainforest. "This little creature is endangered. We need to do something to preserve it," says Schlindwein, a 62-year-old small-scale farmer in Sinop municipality, located within Brazil's central Mato Grosso state. Known locally as zogue-zogue and by scientists as Plecturocebus grovesi, the house cat-sized Groves' Titi is found only in Mato Grosso state, and there are just a few thousand of them left. IMAGES AND SOUNDBITES ARRANGED IN SEQUENCES