Surgeons saved a zoo monkey’s foot from amputation, and months later she gave birth

A critically endangered monkey at a zoo in England has become an unlikely case study in what veterinary teams will attempt to keep a rare species breeding. Masaya, a 15-year-old roloway monkey, developed a golf-ball-sized mass on her foot that would ordinarily have led to amputation. Instead, a joint team of zoo veterinarians and university surgeons tried an operation nobody could find a precedent for in her species. Months later, Masaya gave birth to a healthy daughter, and the foot she nearly lost turned out to matter more than anyone expected.

A Golf-Ball-Sized Mass and a Last Chance

Masaya’s foot problems began not long after she arrived at Chester Zoo in 2023, recurring despite X-rays, ultrasounds and biopsies that failed to pin down a clear cause. Veterinarians eventually suspected a persistent abscess, possibly stemming from an old thorn injury, but by 2025 the swelling had worsened enough that the zoo’s Animal Health Centre team decided Masaya needed more detailed imaging than they could provide on site. She was transported to the University of Liverpool for a CT scan, an unusual trip for a primate that required the team to bring anesthesia equipment, medication and blankets in case anything went wrong along the way. Veterinary officer Charlotte Bentley later said it was “not every day you take a monkey to vet school,” and that the scan results left the team with a clear choice between surgery and amputation.

Chester Zoo and Liverpool Surgeons Save the Foot

The scan led to a complex operation carried out jointly by Chester Zoo vets and surgeons from the University of Liverpool’s Small Animal Teaching Hospital, aimed at removing the mass while preserving as much of the foot as possible. According to Chester Zoo’s account of the surgery, the medical team could not find any previous record of the same procedure being performed on a roloway monkey, yet the operation succeeded well enough that Masaya kept all but one of her toes. Veterinarian Rachel Burrow, who helped lead both the scan and the surgery at Liverpool, said working with a primate was a marked departure from her usual patients of cats and dogs, calling it a privilege to treat such a rare animal, and reported that Masaya recovered comfortable, active and using the limb normally in the weeks that followed.

A Birth That Depended on a Working Foot

The stakes of the surgery became clearer months later, when Masaya gave birth to a daughter named Lagertha. A report on the case notes that if the foot had been amputated, zoo staff would have faced real uncertainty about whether Masaya could still hold and carry her offspring or carry out other normal parenting behaviors. Primate keeper Zoe Edwards said Masaya is parenting “magnificently,” and that the newborn, only a few weeks old, is already curious about her habitat and the keepers who look after her. Lagertha is Masaya’s third daughter, and the healthy birth removed any lingering doubt about how completely the surgery had preserved normal function in the limb, since a monkey unable to grip securely would struggle to keep an infant safe while climbing or foraging.

One Family the Breeding Programme Is Counting On

Masaya lives at Chester Zoo alongside her mate, Grizu, and their two sons, Anum and Ilo, a family group zoo staff once described as “incredibly special” given how rarely roloway monkeys reach UK collections at all. Mike Jordan, the zoo’s director of animal and plant care, has said the species has lost around 90 percent of its population in recent decades, driven by deforestation, agricultural expansion and poaching for meat and fur across Ivory Coast and Ghana, and that conservation zoos now carry much of the responsibility for keeping the species from disappearing in the wild altogether. Masaya’s surgery and Lagertha’s birth therefore involved more than one animal’s recovery: they kept an entire family unit intact within a breeding programme that has very few roloway females left to work with.

Why One Monkey’s Recovery Matters for Her Species

Chester Zoo is one of only two locations in the United Kingdom that houses roloway monkeys, and Masaya is considered particularly valuable within the European Endangered Species Programme, the coordinated breeding effort designed to safeguard the species. The species faces habitat loss and poaching across its range in Ghana and Ivory Coast, where the International Union for Conservation of Nature estimates fewer than 2,000 roloway monkeys remain in the wild. With only a handful of breeding females across European zoos, the health of individual animals such as Masaya carries outsized weight for the species’ prospects, making the outcome of her surgery significant well beyond her own recovery, and Lagertha’s birth a small but meaningful addition to a population that conservationists are working hard to keep from shrinking further.

Lagertha’s Place at Chester Zoo

Lagertha, whose name comes from a legendary Viking queen, can now be seen with Masaya and four other monkeys in the zoo’s roloway habitat. Zoo staff say the pairing offers the public a rare chance to see a species most visitors will never encounter outside a handful of protected reserves in West Africa, at a moment when many primate populations continue to decline. For the veterinary and conservation teams involved, the birth serves as confirmation that an experimental surgery, attempted with no guarantee of success, achieved more than saving a single limb: it kept an entire genetic lineage viable within a shrinking global population.

This article was created with the assistance of AI and reviewed by an editor.

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