A new book reexamines the mutiny on the Bounty, but science offers a deeper account of its cause

The most common explanation for the Bounty mutiny pits a humane Fletcher Christian against an oppressive William Bligh. In her 2003 revisionist book, The Bounty, Caroline Alexander recasts Bligh as hero and Christian as coward. After 400 pages of gripping narrative, Alexander hints that the mutiny might have involved “the seductions of Tahiti” and “Bligh’s harsh tongue” but concludes that it was “a night of drinking and a proud man’s pride, a low moment on one gray dawn, a momentary and fatal slip in a gentleman’s code of discipline.”

A skeptic’s explanation may seem less romantic, but it is more intellectually satisfying because it is extrapolated from scientific evidence and reasoning. There are, in fact, two levels of causality to consider: proximate (immediate historical events) and ultimate (deeper evolutionary motives). Both played a role in the Bounty debacle.

A count of every lash British sailors received from 1765 through 1793 while serving on 15 naval vessels in the Pacific shows that Bligh was not overly abusive compared with contemporaries who did not suffer mutiny. Greg Dening’s Mr. Bligh’s Bad Language computed the average percentage of sailors flogged from information in ships’ logs at 21.5. Bligh’s was 19 percent, lower than James Cook’s 20, 26 and 37 percent, respectively, on his three voyages, and less than half that of George Vancouver’s 45 percent. Vancouver averaged 21 lashes per man, compared with the overall mean of five and Bligh’s 1.5.

If unusually harsh punishment didn’t cause the mutiny, what did? Although Bligh preceded Charles Darwin by nearly a century, the ship commander comes closest to capturing the ultimate cause: “I can only conjecture that they have Idealy assured themselves of a more happy life among the Otaheitians than they could possibly have in England, which joined to some Female connections has most likely been the leading cause of the whole business.”

Indeed, crews consisted of young men in the prime of sexual life, shaped by evolution to bond in serial monogamy with women of reproductive age. Of the crews who sailed into the Pacific from 1765 through 1793, 82.1 percent were between the ages of 12 and 30, and another 14.3 percent were between 30 and 40. When the men arrived in the South Pacific, the results, from an evolutionary point of view, were not surprising. Of the1,556 sailors, 437 (28 percent) got the “venereals.” The Bounty’s infection rate was among the highest, at 39 percent.

After 10 months at sea, Bligh was not surprised by the reaction to the natives: “The Women are handsome … and have sufficient delicacy to make them admired and beloved — The chiefs have taken such a liking to our People that they have rather encouraged their stay among them than otherwise, and even made promises of large possessions. Under these and many other attendant circumstances equally desirable it is therefore now not to be Wondered at … a Set of Sailors led by Officers and void of connections … should be governed by such powerfull inducement … to fix themselves in the most of plenty in the finest Island in the World where they need not labour, and where the alurements of disipation are more than equal to anything that can be conceived.”

Neuroscience shows that the attachment bonds between men and women, especially in the early stages of a relationship, are chemical in nature and stimulate the pleasure centers of the brain in a manner resembling addictive drugs. In her book The Oxytocin Factor, for example, Kerstin Uvnäs-Moberg shows that oxytocin is secreted into the blood by the pituitary gland during sex, particularly orgasm, and plays a role in pair bonding, an evolutionary adaptation for long-term care of infants.

Ten months at sea weakened home attachments of the Bounty’s crew. New and powerful bonds made through sexual liaisons in Tahiti (that in some cases led to cohabitation and pregnancy) culminated in mutiny 22 days after departure, as the men grew restless to renew those fresh attachments; Christian, in fact, had been plotting for days to escape the Bounty on a raft.

Proximate causes of mutiny may have been alcohol and anger but the ultimate reason was evolutionarily adaptive emotions expressed nonadaptively, with irreversible consequences.