ST. LOUIS — A popular animal at the St. Louis Zoo is celebrating a milestone birthday: Merah (MEER'-ah) the Sumatran orangutan is 50 years old.

Merah reached the half-century mark Monday. She was born May 13, 1969, at a zoo in the Netherlands. She came to St. Louis in 1992.

Merah is a five-time mother, grandmother of two and great-grandmother of one.

The zoo says that when Merah gave birth to Ginger in 2014 at age 45, she became the oldest Sumatran orangutan in the Association of Zoos and Aquariums Orangutan Species Survival Plan to give birth and rear her offspring.

Sumatran, Bornean and Tapanuli orangutan species are classified as critically endangered due to habitat loss. The zoo says fewer than 125,000 orangutans remain in the wild.