In a remarkably rare act, a langur monkey in China's Guangxi province became a midwife when it voluntarily helped another monkey give birth.

Believed to be a practice unique to humans, scientists were amazed that they, for the first time, captured on camera the incident in full detail.

Only once before has a monkey been seen acting as a midwife to another. In 2013, another group of scientists documented a black and white snub-nosed monkey aiding another in childbirth. However, failure to gather details about the monkeys' behavior during the incident and their interactions with one another make this most recent finding rather extraordinary.

This time, lead researcher Meng Yao and his colleagues managed to document every step of the latest incident, described in the journal Primates. The midwife monkey intervened once the baby's head and shoulders had appeared, and quite literally grabbed the infant and pulled it out.

"The behavior was totally unexpected," Yao, an assistant professor at Peking University, Beijing, told BBC Earth. "The other female just actively approached her and took over, and pulled the infant completely out of the birth canal. The mother complied immediately and did not show any resistance."

A surprising discovery considering that usually animals, like the white-headed langur monkey, undergo the miracle of birth alone. In some instances, primates can even assist in their own delivery by pulling as well as pushing her baby out since the newborn comes out facing the mother.

"The mothers always manually self-assisted the delivery, and other individuals only handled the infants hours after birth," Yao explained.

But during this particular event, which took place in the Nongguan Hills, in Guangxi, China, near Peking University's Chongzuo Biodiversity Research Institute, a 14-year-old langur monkey saw the first-time mother, only 5 years old, struggling in delivery and immediately offered her assistance.

What's more, the midwife monkey - who had already given birth herself that same day - sat by the presumably exhausted mother during their first moments together.

Though endemic to the country, this species is particularly rare, BBC added, with fewer than 800 langur monkeys living in the wild, making it among the world's most endangered primates.