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SATURDAY

World of Discovery (ABC, 8-9 p.m.): Di-Di, an orangutan who lived in Tapei, Taiwan, with her adopted family, the Changs, used to enjoy car rides with her ''mother'' (Mrs. Chang). She also understood hundreds of words, used the bathroom, and generally acted like a human being.

At the age of seven, however, she had the strength of several men and a life expectancy of about 50 years. The Changs, who considered her a family member, sadly concluded that the best place for her was back in the wild.

The problem is that such a change is much harder to achieve than the process of domestication. Fortunately for Di-Di, she was given over to Willie Smits, who runs a kind and careful program at the Wanariset Center in Indonesian Borneo. It is designed to return orangutans to a protected rain forest. ''Orangutans: Children of the Forest'' traces the efforts of Dr. Smits to help Di-Di survive in her natural habitat.

The chronicle, a kind of ''Born Free'' for orangutans, also gives viewers an insight into Smits's struggle to save wild orangs from poachers and traders. Di-Di had been smuggled at age one to Taiwan, where young orangs had become saleable as pets, and this program shows Smits as he goes on rescue missions. At one point he visits a flooded area to save young orangutans who would almost certainly have perished.

In Pursuit of Honor (HBO, 8-10 p.m.): Two cavalrymen watch as hundreds of ''excess'' cavalry horses are machine-gunned to death after being driven to Mexico, part of the Army's orders to phase out the cavalry.

The men can't bear to see it continue, rescue the remaining animals, and drive them north toward Canada and freedom -- pursued by a mechanized Army detachment determined to track down the rebels.

It's an unusual plot based on an unusual but true incident, a 1935 military mutiny. Don Johnson stars as the sergeant who instigates the desperate rescue mission.

Please check local listings for these programs.