Gillian Taylor was a 20th-century whale biologist who helped Kirk and Spock bring two humpback whales to the 23rd century and then stayed in the future.
Gillian Taylor was a marine biologist at the Cetacean Institute in Sausalito, California, in 1986. She cared for two humpback whales, George and Gracie, and was distressed that they were about to be released into the open ocean, where whalers could hunt them.
In Star Trek IV: The Voyage Home, Kirk and his crew travelled back in time in a captured Klingon Bird-of-Prey because a probe was devastating Earth while trying to contact humpbacks, which were extinct in their era. Kirk and Spock met Gillian at the institute, and she gradually came to believe their strange story. After the whales were released early, she helped the crew track them down, and she beamed aboard the Bird-of-Prey at the last moment rather than stay behind. Once the whales answered the probe and Earth was saved, Gillian chose to remain in the 23rd century and joined a science vessel.
Gillian's warmth and scepticism made her an ideal guide to the past for the crew, and her role gave the film its strong environmental theme.