Chester Zoo: Bornean orangutan Martha dies aged 59

A great-great-grandmother Martha was known as 'the grand old lady of Chester Zoo'

A 59-year-old orangutan who was "fundamental" to the establishment of a global conservation breeding programme has died, Chester Zoo has announced.

Bornean orangutan Martha was an orphan and had lived at the zoo since 1966.

A great-great-grandmother, Martha was known as "the grand old lady of Chester Zoo".

Zoo keeper Chris Yarwood, who cared for Martha for the past 26 years, said she had been a "true ambassador for her species".

Bornean orangutans are considered critically endangered in the wild due to loss of rainforest habitat and illegal hunting, and have a life expectancy of 40, the zoo said.

Martha moved from a rehabilitation centre in Borneo to Chester Zoo in 1966

It said the loss of rainforest habitat on the island of Borneo, to make way for agriculture, logging and unsustainable oil palm plantations, coupled with illegal hunting and conflict with farmers, has led to a huge decline in Bornean orangutan numbers.

Orphaned as a baby in the 1960s, Martha was raised in care by early pioneering orangutan conservationist, Barbara Harrison, who helped to set up the first orangutan rehabilitation centre in Borneo.

Martha moved to Chester Zoo in 1966 where she went on to become "a hugely influential part of the international conservation breeding programme working to ensure a safety-net population of Bornean orangutans".

She became a great-great-grandmother and lived alongside her two daughters, Sarikei and Leia, and their own offspring, Dot, and a young female born in September 2023.

Martha's daughter Sarikei gave birth to a female in 2023

Vets and primate experts said she had been in good health until recent years when she had developed age-related complications.

"There really aren't enough words to convey the awe and respect that I have for Martha, the grand old lady of Chester Zoo, and it feels incredibly strange to have to say goodbye," Mr Yarwood said.

"Caring for Martha has been a huge privilege. She'll be hugely missed and will always hold a special place in our hearts."

As part of ongoing work to protect the highly endangered species from extinction, a small genetic tissue sample from Martha will be cryogenically frozen and stored to offer future options for conservation, the zoo said.