Critically Endangered Roloway Monkey Gives Birth After Surgery Saved Her Foot

Masaya, a 15-year-old roloway at Chester Zoo, gave birth to a baby named Lagertha less than a year after surgery in 2025 removed a large mass and preserved most of her foot; the zoo says Masaya is active and using the limb well. According to the IUCN, fewer than 2,000 roloway monkeys remain in the wild.

Masaya, a 15-year-old roloway monkey at Chester Zoo, has given birth to a baby named Lagertha less than a year after undergoing major surgery. In the summer of 2025 veterinarians removed a large mass from her foot and preserved all but one toe. Zoo staff worked with specialists from the University of Liverpool's Small Animal Teaching Hospital and used advanced imaging during her treatment. The birth is being highlighted because roloways are critically endangered and the animal was an important breeding female in the European programme. Key details: - Masaya is reported as 15 years old and the newborn has been named Lagertha. - The 2025 procedure removed a mass described as about the size of a golf ball and saved most of her foot. - Chester Zoo veterinarians partnered with the University of Liverpool's Small Animal Teaching Hospital and used advanced imaging as part of care. - Chester Zoo is one of two U.K. locations that house roloway monkeys, and Masaya was considered an important breeding female within the European conservation programme. - According to the International Union for Conservation of Nature, fewer than 2,000 roloway monkeys remain in the wild, with habitat loss and poaching cited as threats. Summary: The successful surgery and subsequent birth remove immediate concerns about Masaya's ability to hold and care for her offspring and are noted as supportive of the zoo's conservation role. Masaya is reported as active, comfortable and using the limb well while caring for her newborn. Undetermined at this time.