A heartwarming conservation success story has unfolded at Chester Zoo in the UK, where a critically endangered roloway monkey named Masaya has welcomed a healthy baby girl just months after undergoing complex surgery that saved her foot from amputation. The birth, announced in March 2026, offers renewed hope for one of the world’s rarest primate species and highlights the dedication of zoo veterinarians and human medical experts working together.
Masaya, a 15-year-old female roloway monkey, developed a golf-ball-sized mass on her foot believed to stem from an old thorn injury. Over time the growth worsened despite various treatments, threatening her entire foot and mobility. Without intervention, amputation seemed inevitable, which would have severely impacted her ability to care for offspring in the future.
In summer 2025, vets at Chester Zoo collaborated with specialist surgeons from the University of Liverpool’s Small Animal Teaching Hospital to perform a pioneering procedure. Since no prior records existed of this type of surgery on a roloway monkey, the team adapted techniques from human and small animal medicine. They successfully removed the mass while preserving all but one of Masaya’s toes, allowing her to retain full use of her foot.
The recovery process required careful monitoring, pain management, and rehabilitation, but Masaya responded remarkably well. Zoo staff noted her resilience throughout, and within months she was moving comfortably again. Then, in early 2026, she gave birth to a daughter named Lagertha — Masaya’s third offspring and a vital addition to the captive breeding program.
Roloway monkeys are among the most endangered primates on the planet, with fewer than 2,000 individuals estimated to remain in the wild across Ghana and Ivory Coast. Habitat loss, hunting, and the bushmeat trade have pushed the species toward extinction. Every successful birth in accredited zoos like Chester plays a crucial role in maintaining genetic diversity and supporting long-term survival efforts.
Keepers described Lagertha as strong and lively, already bonding closely with her mother. The baby’s arrival has boosted morale among the conservation team and drawn attention to the broader challenges facing roloway monkeys. Zoo officials emphasized that Masaya’s story demonstrates how advanced veterinary care, combined with international collaboration, can make a tangible difference for critically endangered animals.
This case also underscores the value of zoos as centers for both animal welfare and species preservation. By applying cutting-edge surgical techniques and providing expert post-operative care, Chester Zoo has helped ensure Masaya can continue contributing to the breeding population. The successful outcome serves as inspiration for similar efforts with other rare primates facing medical challenges.
As Lagertha grows under the watchful eyes of her mother and dedicated keepers, her story brings a message of resilience and hope. In a world where many species teeter on the brink, small victories like this one highlight the impact of compassionate science and committed conservation work.