Onstage at a New Hampshire campaign event on Wednesday night, former president Donald Trump bragged about many things: his immigration policies, his passage of a tax cut, the unemployment rates during his administration.

He also bragged about how he recently correctly identified a whale on a cognitive test.

“I think it was 30, 35 questions,” the former president said of the test, which he said involved a few animal-identification questions. “They always show you the first one, like a giraffe, a tiger, or this, or that, and then: a whale. ‘Which one is the whale?’ Okay. And that goes on for three or four [questions] and then it gets harder, and harder, and harder.”

Trump, 77, said he aced the exam, which he said he took to silence the critics who claim he may be too old or cognitively incapable to run for president.

Chief among those critics is former U.N. ambassador Nikki Haley, who — to gain ground on Trump ahead of the New Hampshire primary — has sharpened her pitch against him by doubling down on questioning his age and cognitive abilities.

Since the beginning of her campaign, the 51-year-old Haley has proposed that politicians and lawmakers over the age of 75 be required to take a “mental competency test” before they’re allowed another term in office. And while she has mainly targeted President Biden’s age — 81 — on the trail, in recent days she’s also been drawing in Trump when arguing that the country needs younger leaders.

After finishing third in the Iowa caucuses behind Trump and Florida Gov. Ron DeSantis, Haley has repeatedly pointed to Trump’s age as an attack line in television ads and media interviews ahead of the crucial New Hampshire primary next week.

“The majority of Americans think that having two 80-year-olds running for president is not what they want,” she said at a campaign stop Tuesday in Bretton Woods, N.H. On Wednesday and Thursday, she more than once accused Trump of throwing a “temper tantrum.”

The attacks appear to be bothering the former president, who on Wednesday night spent a good portion of his remarks talking about how young he feels and boasting about his cognitive abilities.

“I feel like I’m about 35 years old,” he said. “I actually feel better now than I did 30 years ago. Tell me, is that crazy? I feel better now, and I think cognitively I’m better than I was 20 years ago. I don’t know why.”

A spokesman for Trump did not immediately respond to requests for comment on Haley’s attacks on the former president’s age. The campaigns of both Biden and Trump as well as experts on aging have stated that the two remain physically capable of being president even with demanding schedules. Each candidate disclosed positive health reports from their physicians during this campaign cycle.

While Haley, like other GOP candidates, attacked Biden for his age — saying point-blank in a recent television advertisement that “Biden is too old” — she had largely avoided reminding voters that Trump, the GOP’s longtime front-runner, is a septuagenarian.

But now that the GOP field has slimmed, and she appears to be gaining ground against the former president in New Hampshire, Haley has begun more explicitly drawing similarities between Trump and Biden’s age to pull voters away from the Republican leader.

The strategy may be working on voters like Mark Green, a 68-year-old New Hampshire resident who, during a Haley campaign event on Thursday, said some Republican voters are “hopeful for an alternative to Trump.’

“I think for Nikki Haley, having somebody new and younger and more diplomatic, to be able to speak and not alienate people, I think that’s a huge thing,” he said.

Doug Heye, a longtime Republican strategist, told The Washington Post that Haley’s newfound interest in highlighting her former boss’s age “can certainly affect Trump.”

“We — both voters and Republicans — focus a lot on Biden’s age, and with good reason,” Heye said. “Trump’s age has not received the same scrutiny.”

While 86 percent of Republican and Republican-leaning independents say Biden is too old to be president, 34 percent of those same voters thought the same about Trump, according to a Marquette Law School poll from early November.

Heye suggested that is partially a result of Trump’s campaigning style — particularly his refusal to debate his opponents, choosing instead to address his base at grand-scale political rallies, something he’s done for nearly a decade.

“Much of Trump’s base is unshakable, and while he is a ball of energy, should he do something that shows his age wearing on him, there will be a negative reaction,” Heye said.

At Wednesday night’s campaign event, Trump dismissed suggestions that he is not cognitively sharp enough anymore to run for the White House.

“Cognitively? I mean, I’m up here making a speech with no notes,” the former president said. “I’ve got these teleprompters, I haven’t started practically reading them yet.”

Colby Itkowitz and Dylan Wells contributed to this report from New Hampshire.