Moby Dick is based on Mocha Dick, a real albino whale that destroyed over
20 whaling ships in the 1830s.

The inspiration for Herman Melville's 1851 novel Moby Dick was based on a
real albino sperm whale called Mocha Dick. During the growth of the whaling
industry in the Americas in the mid 1800s, Mocha Dick gained a reputation
of being a one of the most feared whales in the ocean. Mocha Dick was
reported to be docile if left alone, even swimming along ships. However,
when provoked, the 70 foot (21.336 m) whale would become aggressive and
attack ships with his body. During the 28 years that Mocha Dick hunted, he
reportedly attacked 100 ships, 20 of which were completely destroyed. Mocha
was eventually killed by whalers in 1838 near the Chilean island Mocha
after he came to the rescue of a female whale whose calf was killed by the
whalers.