Roloway monkey gives birth after foot-saving surgery
Bottom line
A critically endangered roloway monkey at Chester Zoo has given birth months after a limb-sparing surgery removed a golf-ball-sized mass from her foot, avoiding amputation. The 15-year-old female, Masaya, underwent the procedure last summer after recurring foot problems worsened and a CT scan at the University of Liverpool’s Small Animal Teaching Hospital helped the team decide surgery was the best option. Zoo and university clinicians said they found no previous examples of the procedure in roloway monkeys, and the operation preserved all but one toe. Her infant daughter, Lagertha, was announced by Chester Zoo on March 18, 2026. (chesterzoo.org)
Why it matters: For veterinary professionals, the case is a useful example of how advanced imaging, cross-institutional referral, and species-specific surgical decision-making can support both welfare and conservation goals in rare primates. Chester Zoo said Masaya’s ability to keep using the limb normally mattered not only for comfort and mobility, but also for maternal behavior after birth. That’s especially relevant in a species with fewer than 2,000 individuals believed to remain in the wild and only a small number of breeding females in European collections managed through conservation programs. (chesterzoo.org)
What to watch: Watch for any formal case report or conference presentation that details the imaging findings, surgical technique, pathology, and postoperative management, because those specifics could help guide future exotic and zoo medicine cases. (chesterzoo.org)
Key facts
- Species
- Roloway monkey
- Individual
- Masaya, a 15-year-old female
- Procedure
- Limb-sparing surgery to remove a golf-ball-sized mass from her foot
- Outcome
- The surgery preserved the foot and all but one toe, avoiding amputation
- Imaging
- CT scan at the University of Liverpool’s Small Animal Teaching Hospital helped guide the decision
- Birth announcement
- Her daughter, Lagertha, was announced by Chester Zoo on March 18, 2026
- Clinical context
- Chester Zoo said there were no previous examples of the procedure in roloway monkeys
- Conservation status
- Critically endangered, with fewer than 2,000 believed to remain in the wild
A conservation-sensitive surgical case at Chester Zoo has turned into a breeding success story: Masaya, a 15-year-old roloway monkey, gave birth after a foot-saving operation removed a large mass that otherwise may have led to amputation. Chester Zoo announced the birth of her daughter, Lagertha, on March 18, 2026, framing it as both a clinical milestone and a meaningful development for one of the world’s rarest primates. (chesterzoo.org)
The background is what makes the case notable. According to Chester Zoo, Masaya had recurring foot problems since arriving in 2023. X-rays, ultrasound, and biopsies did not yield a clear answer, and clinicians ultimately suspected a persistent abscess, possibly linked to an old thorn injury. When the swelling worsened in 2025, the zoo referred her for CT imaging at the University of Liverpool’s Small Animal Teaching Hospital, where the team concluded surgery was the best remaining option before amputation. (chesterzoo.org)
The procedure itself appears to have been unusual for the species. Chester Zoo said the team could not find previous examples of the same operation in roloway monkeys, but surgeons were able to preserve the foot and all but one toe. That matters clinically because limb function in arboreal primates affects far more than ambulation: grasping, climbing, infant carrying, and social behavior all depend on it. Postoperatively, the zoo reported that Masaya was comfortable, active, and using the limb well. (chesterzoo.org)
The public-facing expert reaction came mainly from the treating institutions. Zoo veterinary officer Charlotte Bentley described the logistical complexity of transporting a monkey for advanced imaging, while University of Liverpool veterinarian Rachel Burrow said the surgery was effectively the last chance to save the foot before amputation. Chester Zoo primate keeper Zoe Edwards added that if Masaya had lost the limb, there would have been real uncertainty about her ability to hold an infant and maintain normal behavior. Those comments don’t substitute for a peer-reviewed case report, but they do highlight the practical thinking behind the intervention. (chesterzoo.org)
The conservation context is substantial. The IUCN has said the roloway monkey is Critically Endangered, with fewer than 2,000 individuals thought to survive in Ghana and Côte d’Ivoire. Chester Zoo also noted that Masaya is among only a few breeding females in European zoos. EAZA describes its Ex situ Programmes as coordinated population-management efforts designed to maintain healthy, genetically diverse populations across member institutions, and roloway monkeys are among the species managed within that framework. (iucn.org)
Why it matters: For veterinarians, this story lands at the intersection of zoo medicine, surgery, imaging, anesthesia, welfare, and population management. It shows how referral-level diagnostics can change the trajectory of a case even when first-line workups are inconclusive. It also underscores that, in endangered species, preserving function may carry reproductive and behavioral consequences that go well beyond the immediate lesion. For teams caring for nontraditional species, that’s a reminder that case planning often has to account for maternal performance, social integration, and breeding-program value alongside standard surgical goals. (chesterzoo.org)
There are still important unknowns. Neither the Chester Zoo nor University of Liverpool announcement appears to include a pathology diagnosis, detailed anesthetic protocol, rehabilitation plan, or long-term orthopedic follow-up. No peer-reviewed paper or formal case report surfaced in this search, so some of the most useful lessons for clinicians, including differential diagnosis, surgical approach, and postoperative management, remain unpublished or at least not easily accessible yet. (chesterzoo.org)
What to watch: The next meaningful development would be a conference abstract, case report, or institutional clinical write-up that fills in those missing details, along with any update on Lagertha’s progress and Masaya’s long-term limb function within the European breeding program. (chesterzoo.org)