A critically endangered roloway monkey has given birth only months after a pioneering operation spared her from having her foot amputated.
Masaya, a 15-year-old roloway monkey living at Chester Zoo, underwent complex surgery last summer after developing a golf-ball-sized mass on her foot. Zoo veterinarians worked with surgeons from the University of Liverpool’s Small Animal Teaching Hospital to remove the mass and preserve as much of the foot as possible.
The medical team could find no previous examples of the same procedure being performed on a roloway monkey. Even so, the operation was successful, allowing Masaya to keep all but one of her toes.
Now, Masaya has welcomed a daughter named Lagertha. Primate specialists at Chester Zoo say the young monkey is already showing some of the same character as her mother.
A Last Chance to Save Masaya’s Foot
Rachel Burrow, a veterinarian and lecturer at the University of Liverpool, helped with both Masaya’s CT scan and the subsequent operation.
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.”
The success of the procedure became even more important after Masaya gave birth. Being able to use her foot normally could play a crucial role in her ability to carry and care for her offspring.
Zoe Edwards, 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.”
A Significant Birth for a Critically Endangered Species
Lagertha is Masaya’s third daughter, making the birth especially valuable for a species facing an uncertain future.
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. Their natural range includes Ghana and the Ivory Coast, where the animals are threatened by both habitat destruction and poaching.
Because the species is so rare, the health and reproductive success of individual animals such as Masaya can have wider importance. She is part of the European Endangered Species Programme, a coordinated breeding effort designed to help safeguard the species from extinction.
Years of Mysterious Foot Problems
Masaya’s foot problems began before the operation and had repeatedly troubled her since she arrived at Chester Zoo in 2023.
Veterinarians carried out X-rays, ultrasounds and biopsies, but the underlying cause remained difficult to determine. They eventually suspected that Masaya had a persistent abscess, possibly caused by an old injury from a thorn.
By 2025, the swelling had become worse. Zoo staff decided Masaya needed more detailed imaging and transported her 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 anesthesia 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 has since recovered well, and her new daughter is thriving alongside her.
Lagertha, whose name comes from a Viking queen, can now be seen with Masaya and four other monkeys at Chester Zoo.
