A bonobo has been seen giving birth in the wild, the first time scientists have ever documented this most personal of moments occurring in the ape’s natural environment.

Bonobos (Pan paniscus) are the smaller of the two chimpanzee species, living in central Africa.

They are also among the least studied and understood of the great apes, which include gorillas, orang-utans, and the common chimpanzee (Pan troglodytes).

During the birth event, which occurred at the Luikotale Bonobo Project field site, in the Democratic Republic of the Congo, the researchers discovered that wild bonobos do not give birth alone.

The new mother, a female called Luna, was surrounded by two other female bonobos offering companionship and support.

The birth also took place high up in a tree, rather than on the ground.

She sat facing me, and almost appeared to be showing me her new infant

And shortly after the birth, the new mother and other females ate parts of the placenta.

All these behaviours are new discoveries for wild bonobos, and are reported in the journal Primates.

Each provides invaluable information about how wild bonobos live and reproduce, and also about how captive bonobos should be cared for.

A rare day birth

Wild birth events in great apes are rarely observed.

Researchers often have to spend years following the same groups of apes, in order to gain their trust.

So there are few places in the world where scientists can regularly get close enough to apes to witness their normal behaviour.

Primates, including great apes, are also thought to often give birth at night, which makes it extremely difficult for people to observe the event happening.

Luna’s birth, however, occurred in late morning.

It was observed and documented by primatologist Pamela Heidi Douglas, of the Max Planck Institute for Evolutionary Anthropology in Leipzig Germany.

For almost two years, Douglas has followed and studied the bonobos at Luikotale, as part of her research towards her PhD.

We detected Luna’s pregnancy not long after conception

“One component of my Ph.D. research is the study of reproductive endocrinology in female bonobos,” she told BBC Earth.

To do this, Douglas regularly collected urine samples from Luna and other females in the community on a regular basis.

These were tested with human pregnancy kits, which can detect pregnancy in bonobos as well as other non-human primates.

“We detected Luna’s pregnancy not long after conception,” said Douglas.

One week before giving birth, Luna’s abdomen was visibly distended and “on the morning of her delivery, I noticed the presence of an unusual white lump, or mucous plug, in her sexual swelling, but I did not know that parturition was imminent.”

Luna gave birth in a nest, a collection of leaves and branches built in a tree, in which bonobos rest.

“I heard high‐pitched, soft vocalisations emanating from her nest for an unusually prolonged period of time, but it was the reactions of the two attending females that made me realise that Luna had gone into labour.”

The two attending female bonobos not only encircled the nest, but Luna allowed one to enter the nest during the delivery.

Luna also allowed the two females to feed on the placenta, after the birth.

Use of midwives?

Scientists have assumed that many primates prefer to give birth alone.

But in recent years, that hypothesis has been questioned.

In her review of 39 births recorded across 31 primate species in the wild, Douglas found that only five delivered their baby in isolation.

The birth of the wild bonobo supports the idea that many primates actually give birth in the company of others.

In two species of monkey, other females have even been recorded acting as midwives, helping the mother deliver her baby.

The birth of Luna’s baby also confirmed that bonobos, like many other mammal species, eat the placenta after birth.

That suggests that the placenta should be left with bonobos that give birth in captivity, rather than being removed as is often the case.

Thrilling encounter

“It was thrilling to be present during the event, just metres below Luna’s nest,” said Douglas.

Bonobos were the last species of great ape both to be discovered and to be studied in the wild, she adds, and live only in Democratic Republic of Congo.

Years of civil unrest in the region has greatly compromised the ability of researchers to study bonobos there.

However, the field site at Luikotale offers rare opportunities to study never-before-seen behaviours, “a privilege which is both rare and priceless” said Douglas.

“When Luna emerged from her nest with her newborn, she sat calmly in the tree for a few moments, providing me a long, unobstructed view of her newborn.”

“Other females in the community have acted nervous around human observers for a period of days, or even weeks, following the birth of a new infant, but this was not the case with Luna.”

“She sat facing me, and almost appeared to be showing me her new infant. It certainly was one of my most unforgettable days of nearly twenty months in the forest with the bonobos.”

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