Suzi Eszterhas / Red-shanked douc langur (Pygathrix nemaeus) infant sucking thumb while caretaker holds it. Animal was rescued from illegal wildlife trade, Endangered Primate Rescue Center, Cuc Phuong National Park, V...

Matthew Maran / Red shanked douc langur (Pygathrix nemaeus) Son Tra Nature Reserve, Vietnam

Thomas Marent / Douc Langur (Pygathrix nemaeus) male, native to southeast Asia

Rod Williams / Head portrait of male Douc Langur, endangered species occurs Vietnam

Rod Williams / Head portrait of male Douc Langur, endangered species, occurs Vietnam

Matthew Maran / Red-shanked douc (Pygathrix nemaeus) feeding on leaves, Son Tra Nature Reserve, Vietnam, 2018.

Matthew Maran / Red-shanked douc (Pygathrix nemaeus) feeding on leaves, Son Tra Nature Reserve, Vietnam, 2018.

Suzi Eszterhas / Red-shanked douc langur (Pygathrix nemaeus) infant rescued from illegal wildlife trade, Endangered Primate Rescue Center, Cuc Phuong National Park, Vietnam

Suzi Eszterhas / Bui Thi Hanh, animal caretaker, holding infant Red-shanked douc langur (Pygathrix nemaeus) and infant Grey-shanked douc langur (Pygathrix cinerea) that were rescued from illegal wildlife trade Endang...

Suzi Eszterhas / Red-shanked douc langur (Pygathrix nemaeus) infant that was rescued from illegal wildlife trade Endangered Primate Rescue Center, Cuc Phuong National Park, Vietnam

Suzi Eszterhas / Nguyen Thi Thi Phuong, Animal Caretaker, holding infant Red-shanked douc langur (Pygathrix nemaeus) which was rescued from illegal wildlife trade. Endangered Primate Rescue Center, Cuc Phuong National...

Suzi Eszterhas / Bui Thi Hanh, Animal Caretaker, bottle-feeding infant Red-shanked douc langur (Pygathrix nemaeus) that was rescued from illegal wildlife trade, Endangered Primate Rescue Center, Cuc Phuong National Pa...