Fatou, a gorilla described by Zoo Berlin as the world's oldest, celebrated her 69th birthday on Monday with a bamboo bouquet and a basket of vegetables.

"That age is very unusual for a gorilla," said zookeeper Christian Aust, as gorillas in the wild typically live between 35 and 45 years, according to a zoo press release.

To mark the occasion, the female gorilla was given lettuce, tomatoes, beetroot and broccoli. Fruit is no longer part of her diet because of its high sugar content and the risk of obesity and metabolic disorders.

Fatou arrived in the German capital in 1959 and has been living in a separate enclosure away from the zoo's younger gorillas to enjoy a quieter environment. Her health is being closely monitored.

"She has arthritis; she can no longer fully extend her joints, so she can't completely straighten her legs and arms," said curator Jennifer Hahn. Despite this, Fatou is still able to move around quite well.

The zoo said animals in human care often live significantly longer than those in the wild because they are protected from predators and receive regular veterinary care.

In their natural habitat, older and weaker animals are more vulnerable to predators, rivals and food shortages.