This year’s scientific discoveries that made us say ‘Huh?’

Every school child learns (wrongly) that Archimedes yelled “Eureka” when he discovered the principle of buoyancy while taking a bath.

The story is apocryphal, and in fact, such flashes of inspiration are rare in science. Discoveries most often arise from hours of painstaking and frustrating work in the lab. Far more common than these “Aha!” moments this year were head-scratching insights that we have dubbed “Huh?” moments.

Here are our favorite “Huh?” moments of 2016. We’re eager to hear yours as well, in the comments section below.

1. Ticklish rodents

We humans are not — as thinkers going back to Aristotle thought — uniquely ticklish: Rats are too. This discovery was called “innovative and groundbreaking,” but the best part was the realization that some scientists spend their days tickling rats. Shimpei Ishiyama, a post-doc at Humboldt University in Berlin, who introduces himself at parties and bars as the “rat tickler,” reported that the critters squeaked and jumped with pleasure when he tickled their backs and bellies. These signs of joy changed according to their mood. It remains a mystery, though, why tickling has been conserved by evolution and has such a powerful impact on us — and rats.

2. Pain is contagious

Rodents were the source of another strange finding this year: Sensitivity to pain can be spread by smell. Alcohol withdrawal makes mice and people feel pain more acutely, but researchers at Oregon Health and Sciences University found that mice living in the same room as animals going through withdrawal became similarly sensitized to pain. When bedding from the mice undergoing withdrawal was then put in the cages of mice in another room, they too became less pain-tolerant — suggesting scent was the culprit. If the finding is borne out, it could mean that mouse experiments on everything from drug withdrawal to painkillers could have been skewed, the researchers said.

3. Virginity genes

Genetics may account for up to one-quarter of the difference in the ages when people start having sex, University of Cambridge geneticist John Perry reported. “Sure, choice has a massive role in this, but there are biological and genetic factors, too,” he said. While the study of more than 125,000 people in the UK, Iceland and the United States didn’t prove cause and effect, it found associations between the timing of first sexual experiences and gene variants corresponding with fertility, start of puberty, and propensity to take risks.

4. The bigger the yawn, the bigger the brain

Yawning may be more than merely a sign of exhaustion. Scientists have theorized that stretching our jaws and sucking in air cools the brain and can increase blood flow, suggesting that yawn duration should correlate with brain size and complexity. Indeed, a psychologist at the State University of New York at Oneonta found that the average duration of yawns in 109 individuals from 19 species — including humans, African elephants, walruses and rabbits — predicted a species’ brain weight and its number of cortical neurons. The average dog yawn, by the way, was .43 seconds longer than the average for cats.

5. Happy heart syndrome

It’s not just sadness that can break your heart. So can moments of extreme joy, such as your wedding or the Cubs finally winning the World Series. In a condition known as takotsubo cardiomyopathy, part of the heart freezes up temporarily, causing it to resemble a takotsubo, or Japanese octopus trap. The vast majority of these cases are triggered by intense negative emotions, but a University Hospital Zurich physician reported identifying 20 patients whose condition, which results in irregular blood flow, was sparked by elation.

So, New Year’s Eve revelers, don’t go too crazy when the ball drops on 2016.