Japanese author and animal researcher Masanori Hata, who frequently appeared on television shows about animals and was better known by his nickname "Mutsugoro," died Wednesday of a heart attack, his family said. He was 87.

He founded a facility called "Animal Kingdom" in Hokkaido, where he lived with various animals including dogs and bears. A TV program featuring his life with animals became popular in the country, airing for more than 20 years from 1980.

Born in the city of Fukuoka, Hata graduated from the University of Tokyo's School of Science. He later joined an educational publishing firm where he created documentary films about animals.

After leaving the company in 1968, Hata started writing books, winning the Kikuchi Kan Prize in 1977 for his achievements in animal literature.

He became well known among TV audiences for his displays of affection toward animals, even once gently patting a lion that had bitten his finger.

In 1986, Hata also directed the film "The Adventures of Milo and Otis" featuring a kitten and a pug, which became a success in Japan.