Edward Prendick was an English biologist. At sea in February, 1887, he was aboard the doomed ship the Lady Vain when it collided with another ship and sank. He, Helmar and a third man survived and drifted in a lifeboat, however the other two killed each other fighting over water, leaving only Prendick to be picked up by the passing Ipecacuanha. Here Prendick met and befriended Montgomery, who along with a cargo of animals was bound for an island which Montgomery did not identify.
En route, Prendick intervened on the behalf of M'Ling who was being tormented by Captain Davis. As a result, upon arriving at the island, an incensed Davis forced Prendick ashore, where he met, but decidedly did not befriend, the mysterious Dr. Moreau. Prendick was given a room and told to stay out of Moreau's laboratory although he heard an animal's cries of pain coming from them. This made him remember he had heard Moreau's name before, in a vivisection scandal in London some years before.
When the cries coming from Moreau's lab became unmistakably human, Prendick, fearing that the scientist vivisected human beings, fled into the jungle, where he encountered the fruits of Moreau's experiments, the "beast people." This only seemed to confirm Prendick's suspicions about Moreau's work, although later, Moreau explained that Prendick had it backwards: he wasn't vivisecting humans, but rather using surgery to artificially evolve animals into humans. This did little to change Prendick's opinion of the man.
After Moreau died at the hands of one of his own half-finished creations, Prendick attempted to prevent anarchy by telling the beast people that Moreau's spirit watched over them always. However a grief-stricken Montgomery, becoming drunk, gave liquor to the beast people and subsequently got himself and several of them killed in a drunken brawl, leaving Prendick the only human being on the island as the beast people began devolving. He did befriend one beast man, though, who had once been a St. Bernard dog and became Prendick's loyal friend.
Prendick's enemy on the island was the vicious, antagonistic "hyena-swine," who killed the St. Bernard beast man and was himself eventually slain by Prendick's revolver. The beast people continued becoming more and more animalistic, threatening Prendick's life, until by chance, one year later in early 1888, a dinghy from the Ipecacuanha carrying two corpses (one of which was none other than Captain Davis) washed ashore, and in this, Prendick escaped Dr. Moreau's island.
Picked up by another passing ship, the Myrtle, he was thought insane by the crew and so upon returning to England, avoided mentioning his story, claiming to have suffered amnesia after the Lady Vain sank. Over time however, he was able to locate a scientist who had known and worked with Moreau and who was able to corroborate his story, and Prendick's own nephew even undertook an expedition to the island (based on his uncle's coordinates), but found that in the intervening years, all of the beast people had died out.
As for Prendick himself, his experiences on the island left him a very paranoid man. Moreau's experiments in turning animals into people made Prendick realize that humans aren't that different from animals and thus he saw, in his fellow Englishmen, various animalistic traits which worried him. Apart from his nephew, he lived the remainder of his life in solitude and in pursuit of milder sciences.