Critically Endangered Roloway Monkey Welcomes a Baby at Chester Zoo After Pioneering Foot Surgery
A remarkable story of survival and new life is unfolding at Chester Zoo in England, where a critically endangered roloway monkey has given birth just months after groundbreaking surgery saved her from a life-altering amputation. Masaya, a 15-year-old roloway monkey, had a golf-ball-sized mass removed from her foot last summer in a complex operation carried out jointly by zoo vets and surgeons from the University of Liverpool’s Small Animal Teaching Hospital. The procedure was unlike anything that had been attempted before on this species, making the outcome all the more extraordinary. Against the odds, Masaya not only recovered fully but went on to do what she does best — become a mother again.
Despite finding no previous examples of the procedure on roloway monkeys, the team successfully conducted surgery to save all but one of her toes. Now, she has given birth to little Lagertha, who primate experts at the zoo say is already showing signs of her mother’s spirit. The baby’s name was inspired by the legendary Viking queen, a fitting tribute to a newborn whose very existence required a battle to secure. Lagertha is Masaya’s third daughter, and for the keepers who have watched Masaya through her ordeal, the birth feels like a genuine triumph.
Zoe Edwards, primate keeper at Chester Zoo, could not hide her delight at the new arrival. “Masaya is a very experienced mum and she’s parenting magnificently,” she said. “Lagertha is only a few weeks old and is very dinky but already curious about the roloway monkey habitat and inquisitive about us.” Edwards also underlined just how much was riding on the surgery going well, noting that an amputation could have put Masaya’s ability to raise offspring in serious doubt. “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,” she added.
The road to the operating table was a long and frustrating one. Masaya had experienced recurring problems with her foot since she came to the zoo in 2023, and despite x-rays, ultrasounds, and biopsies, vets struggled to identify the cause, eventually concluding it was likely a persistent abscess, possibly from an old thorn injury. When the swelling worsened, the decision was made to transport her to the University of Liverpool for a CT scan. Charlotte Bentley, veterinary officer at the zoo’s animal health centre, described the unusual logistics of the situation. “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,” Bentley said.
For Rachel Burrow, vet and lecturer at the University of Liverpool who played a central role in the operation, the experience was one she will not forget. “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,” Burrow said. The collaborative nature of the procedure, drawing on expertise from both the zoo and a leading university veterinary team, set a new benchmark for what is possible in the care of endangered primates.
The stakes surrounding Masaya’s health extend far beyond Chester Zoo itself. According to the International Union for Conservation of Nature (IUCN), fewer than two thousand roloway monkeys live wild in Ghana and the Ivory Coast, where they face habitat loss and poaching. Hunters and illegal pet dealers have triggered an 80 percent fall in their numbers, and the species now survives only in isolated pockets of old-growth forest. Chester Zoo is one of only two places in the UK that roloway monkeys can be found, and there are only a few breeding females in zoos across Europe. Every healthy birth within the European Endangered Species Programme carries enormous significance for the long-term survival of the species.
Baby Lagertha and her mother Masaya can currently be seen alongside four other roloway monkeys at Chester Zoo, giving visitors a rare chance to witness one of the world’s most endangered primates up close. The arrival of this tiny, curious infant is a reminder of what dedicated conservation medicine can achieve when zoos and universities pool their resources and refuse to give up on an animal in need.
Roloway monkeys are so visually distinctive that they were once thought to be a subspecies of Diana monkey before being reclassified as their own species in the 1980s, a taxonomic shift that helped scientists recognize just how uniquely imperiled they were. The species communicates through an elaborate system of alarm calls that can distinguish between aerial predators like eagles and ground-based threats like leopards, a level of vocal sophistication that researchers continue to study today. Chester Zoo’s roloway group is part of a coordinated European studbook, meaning Lagertha’s birth has likely already been logged by conservation coordinators tracking every individual in the global captive population.
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