Critically Endangered Monkey Defies the Odds With New Baby After Surgery

A rare roloway monkey has welcomed a new baby after surgery saved her foot and protected her ability to care for offspring.

For one of the world’s rarest monkeys, the birth of every infant matters. That’s why conservationists at Chester Zoo are celebrating the arrival of a baby roloway monkey just months after her mother underwent a pioneering operation that saved her from a potentially life-changing foot amputation.

Masaya, a 15-year-old roloway monkey, had a golf ball-sized mass removed from her foot last summer in a complex procedure performed by zoo veterinarians and surgeons from the University of Liverpool’s Small Animal Teaching Hospital. Despite finding no previous records of the surgery being carried out in the species, the team successfully saved all but one of her toes.

Now, Masaya has given birth to a daughter named Lagertha, who primate specialists say is already showing signs of her mother’s resilience.

Rachel Burrow, a veterinarian and lecturer at the University of Liverpool, played an important role in both the CT scan and the surgery. She said: “This was the last chance to save Masaya’s foot before amputation. Working with primates is completely different from my usual patients, who are typically cats and dogs, and it was a real privilege to care for such a rare animal. It’s great to see the surgery was a success – she’s comfortable, active, and using the limb well.”

Zoe Edwards, a primate keeper at Chester Zoo, said: “Masaya is a very experienced mum and she’s parenting magnificently. Lagertha is only a few weeks old and is very dinky, but already curious about the roloway monkey habitat and inquisitive about us.

“The fact Masaya’s foot has healed so well is a huge relief. If she’d had an amputation, we’d have been left with real questions about whether she could hold her offspring or continue with her normal behaviors.”

One birth matters for conservation

Lagertha is Masaya’s third daughter, and her arrival is an important moment for the species.

Zoe added: “Chester Zoo is one of only two places in the UK that roloway monkeys can be found, and Masaya is very important – not just to her family, but to her whole species. There are only a few breeding females in zoos in Europe.”

According to the International Union for Conservation of Nature (IUCN), fewer than two thousand roloway monkeys remain in the wild in Ghana and the Ivory Coast, where habitat loss and poaching threaten their survival. The species is now so rare that the health of individuals such as Masaya is especially important to the European Endangered Species Program, a breeding project created to help secure the species’ future.

Diagnosis led to intervention

Masaya had repeated foot problems after arriving at the zoo in 2023. Although veterinarians used X-rays, ultrasounds, and biopsies, the cause remained difficult to identify. They eventually suspected a persistent abscess, possibly linked to an old thorn injury. When the swelling became worse in 2025, Masaya was taken to Liverpool for a CT scan.

Charlotte Bentley, Veterinary Officer at the zoo’s Animal Health Center, said: “It’s not every day you take a monkey to vet school. We had to bring everything she might need, from anaesthesia equipment to medications and blankets.

“Following the scan, we decided an operation was the way forward. She’s been an absolute trooper all the way through, and I’m just glad we were able to do something for her.”

Masaya and Lagertha, whose name comes from a Viking queen, can now be seen with four other monkeys at Chester Zoo.

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