Gentle giant Graham Lucas, who spent his working life caring for animals at Whipsnade Zoo, has died aged 67.

Graham, a walking encyclopaedia on animals, worked at the zoo for 46 years, and even lived there for some time.

He was a former head keeper on the big cats section, where he was instrumental in the prolific breeding successes of the cheetahs in the 1960s and 1970s.

Tall and well-built, he was a familiar face to regular visitors and took on various roles during his many years at the zoo.

He became an information officer in his later years, and retired in 2007.

Graham, who moved from the zoo to Houghton Regis after his retirement, died from heart failure on October 11.

A zoo spokesman said: "We were very saddened to learn of Graham's death and send our condolences to his family and many friends at this sad time.

"Graham was a very valued member of staff, who served the zoo for a great many years.

"He will be very sadly missed and many of his former colleagues, including both volunteers and staff members, have paid tribute to his dedication and experience."

Friends also remember Graham as a keen letter-writer, who had pen pals around the world.

He wrote articles about animals and their welfare, for a variety of publications.

The theatre was another of his passions, especially musicals, and he acted with an amateur dramatics group for a time.

Graham enjoyed entering competitions, too, and donated various prizes to Hillcrest School, in Houghton Regis.

His funeral was held at The Vale crematorium, in Luton, on November 9.