(intriguing music)
- [Narrator] Deep in the protected
river lands of Guizhou, China,
a forest ranger has forged a special relationship
with some of the rarest monkeys in the world.
(foreign language)
Xiao is tasked with monitoring the monkeys.
It has taken decades of patience
to build a mutually trusting relationship with them.
(foreign language)
Over the past 20 years, Xiao has become an expert
in the group's rituals and behavior
and has given scientists unique insight into the species.
(foreign language)
Under his care, Xiao has seen the number of his group
increase, but the species remains endangered.
(foreign language)