More than a decade after Charles Darwin gave the world “The Origin of Species,” he published a lesser-known tome that connected the world of homo sapiens and lesser species inhabiting Planet Earth: “The Expression of Emotions in Man and Animals.” Therein, amid long discussions of sneering, blushing and smiling, Darwin tackled a gesture as well known to mobsters in Martin Scorsese movies as it is to parents of teenagers: the shrug.

“As shrugging the shoulders generally implies ‘I cannot do this or that,’ so by a slight change, it sometimes implies ‘I won’t do it,'” Darwin wrote. “The movement then expresses a dogged determination not to act.”

Though the shrug existed millennia before Darwin described it — and many cabdrivers, airline ticket agents and rebels without a cause have deployed it since — perhaps no modern politician favors the shrug more than Donald Trump. In photographs, news reports and one presidential debate so far, the Republican candidate is often seen or described as “shrugging” — or, perhaps more often, “shrugging off” — controversy.

In some ways, this “determination not to act,” as Darwin put it, is Trump’s brand: Unlike many others with their eyes on the White House, he refuses to walk back, wiggle around or even tread softly when challenged on his outrageous statements.

Trump’s most recent shrugs came when moderator Megyn Kelly challenged him for allegedly offensive remarks about women, who he’s called “fat pigs, dogs, slobs, [and] disgusting animals,” as Kelly put it. Such remarks, she said, weren’t just aimed at Trump’s longtime foe Rosie O’Donnell.

“Trump’s response: A shrug,” The Washington Post’s Amber Phillips reported. “‘Yes, I’m sure it was,'” he said — later adding that Kelly “had blood coming out of her eyes, blood coming out of her wherever,” and refusing to apologize for the implication that Kelly’s outburst was related to hormones.

Trump also shrugged during the debate when he said he would consider a third-party run.

“He was the only one, in fact,” Phillips wrote. “The crowd booed (some had booed the question too). Trump shrugged.” His explanation, which garnered laughs: “If I’m the nominee, I will pledge I will not run as an independent.”

But all of Trump’s shrugs are not of recent vintage — this is a habit that goes back decades.

Trump shrugged in 1988 when questioned about donations made by some of his businesses to the campaign of a New York City councilman.

“Why not just contribute in your own name?” an official asked, as Newsday reported. “Trump shrugged. Everyone knew where the money came from, he said, so there was certainly no effort at concealment. ‘My attorneys basically said this was the proper way of doing it.'”

Trumped shrugged in 1990 as his Atlantic City properties were running short of cash.

“Mr. Trump has shrugged off such worries,” Canada’s Globe and Mail wrote. “Instead, he has emphasized the upbeat, such as the excellent offers he has received for some of his properties.”

Trump shrugged in 1997 when asked why he had included so many photographs of himself in his third autobiography.

“Asked why he included 54 pictures of himself in the new book, Trump shrugged and said his publisher could have printed plenty more,” the San Francisco Chronicle reported. “‘I gave them a lot of pictures, and they just printed the ones they wanted.'”

Trump shrugged in 2002 discussing the large profit he expected to make from New York’s Trump World Tower.

“The residents in the blocks north, south and west of the Second Avenue site weren’t too keen on having an 810-foot tower parked in the neighborhood,” the Chronicle reported. “Trump shrugged off their concerns. ‘We got approved, and it’s a benefit to the neighborhood.'”

Trump shrugged in 2002 as it became clear that the Central Park Five, convicted of raping a jogger in Central Park in 1989, were not guilty. Trump had taken out ads calling for the return of the death penalty to punish the young men.

“Mr. Trump shrugged off the planned protest,” according to the New York Times. He said: “I don’t mind if they picket. I like pickets.”

The Donald shrugged about the financial crisis in 2007.

“Mr. Trump shrugged off concerns that a crisis in U.S. subprime mortgage lending, which caters to poor credit risks, would spread to the wider property market, including Mr. Trump’s luxury buildings,” the Globe and Mail wrote. “‘I don’t see the subprime problems affecting the higher-end stuff,’ he said. In fact, he is advising investors that there are now great deals in buying subprime mortgages at a discount and repossessed houses at low prices.”

That same year, Rolling Stone reported, in the book “Think BIG and Kick Ass in Business and Life,” Trump dismissed his “financial catastrophes with a snarl and a shrug.”

“I figured it was the bank’s problem, not mine,” he wrote. “What the hell did I care? I actually told one bank, ‘I told you you shouldn’t have loaned me that money. I told you the g_damn deal was no good.'”

In 2011, as he seemed to be gearing up to run for president as a Republican, Trump shrugged at reports that most of his political donations had been to Democrats.

“Trump shrugged,” the Weekly Standard reported. “I’ve had a lot of friends who are Democrats, and a lot of friends who are Republicans,” he said.

The shrugging didn’t end there, of course.

Trump has shrugged off questions about his hiring practices and criticism of illegal immigrants, as well as his criticism of John McCain’s war record. And that’s just in the past month.

In an 2011 exchange, the Donald even shrugged off the idea that there was some hidden emotion behind all the shrugging. Bill O’Reilly of Fox News asked Trump if he was “the most sensitive guy in the world,” pointing out that “you want to kick everybody’s butt, but somebody makes fun of you and you’re all over the place!”

As Mediaite reported: “‘I don’t think I’m that sensitive,’ Trump shrugged.”