TOKYO, March 28 (AFP) - A black spider monkey believed to be the world's oldest monkey other than apes has died at age 53 in Japan, with her friendliness and a late-life love affair with a younger monkey seen as clues to her longevity.

With her affable personality, Buenos was one of the most popular monkeys at Japan Monkey Centre in Aichi, 250 kilometers (155 miles) west of Tokyo. She died of coronary trouble on Saturday.

"Just as we were preparing to apply for the Guinness Book, she passed away peacefully. She was so fond of people. While lying on a bed, she always wanted to hold our hands," said the centre's manager Akira Kato.

On the secrets of her longevity, Kato said: "Her calm and kind personality greatly helped. It made her life stress-free. Also she started living with a young male monkey 10 years ago, which might have excited her."

Black spider monkeys have an average life span of 30-33 years. If Buenos were a human, she could be some 140 to 150 years old, Kato said.

Black spider monkeys have long arms and short legs, which improve their balance while walking. They weigh about seven to nine kilograms (15 to 20 pounds) with a height of 60 to 70 centimeters (24 to 28 inches).

Buenos had a long tail stretching more than 90 centimeters (36 inches) which she used for shaking visitors' hands, Kato said, adding she mostly ate fruit and vegetables.

Larger primates can live much longer than medium-sized monkeys such as Buenos.

According to the Guinness Book of World Records, the oldest non-human primate is Cheeta the chimpanzee, the star of 1930s and 1940s "Tarzan" films of which he is the only surviving cast member.