Scattered amid a relentless barrage of news about COVID-19 case surges, quarantine orders, and medical supply shortages on Twitter this week, some happy stories softened the blows: Swans had returned to deserted Venetian canals. Dolphins too. And a group of elephants had sauntered through a village in Yunnan, China, gotten drunk off corn wine, and passed out in a tea garden.

These reports of wildlife triumphs in countries hard-hit by the novel coronavirus got hundreds of thousands of retweets. They went viral on Instagram and Tik Tok. They made news headlines. If there’s a silver lining of the pandemic, people said, this was it—animals were bouncing back, running free in a humanless world.

But it wasn’t real.

The swans in the viral posts regularly appear in the canals of Burano, a small island in the greater Venice metropolitan area, where the photos were taken. The “Venetian” dolphins were filmed at a port in Sardinia, in the Mediterranean Sea, hundreds of miles away. No one has figured out where the drunken elephant photos came from, but a Chinese news report debunked the viral posts: While elephants did recently come through a village in Yunnan Province, China, their presence isn’t out of the norm, they aren’t the elephants in the viral photos, and they didn’t get drunk and pass out in a tea field.

The phenomenon highlights how quickly eye-popping, too-good-to-be-true rumors can spread in times of crisis. People are compelled to share posts that make them emotional. When we’re feeling stressed, joyous animal footage can be an irresistible salve. The spread of social phenomena is so powerful, 2016 research shows, that it can follow same models that trace the contagion of epidemics.

Kaveri Ganapathy Ahuja’s controversial tweet about the swans that “returned” to Venice canals has hit a million likes.

“Here’s an unexpected side effect of the pandemic,” her tweet reads. “The water flowing through the canals of Venice is clear for the first time in forever. The fish are visible, the swans returned.”

Ahuja, who lives in New Delhi, India, says she saw some photos on social media and decided to put them together in a tweet, unaware that the swans were already regulars in Burano before the coronavirus tore across Italy.

“The tweet was just about sharing something that brought me joy in these gloomy times,” she says. She never expected it to go viral, or to cause any harm. “I wish there was an edit option on Twitter just for moments like this,” Ahuja says.

Nonetheless, she hasn’t deleted the tweet and doesn’t plan to, arguing that it’s still relevant because waters in Venice are clearer than usual—a result of decreased boat activity—and that’s what matters, she says. She’s tweeted about the “unprecedented” number of likes and retweets she’s received on the tweet. “It’s a personal record for me, and I would not like to delete it,” she says.

Paulo Ordoveza is a web developer and image verification expert who runs the Twitter account @picpedant, where he debunks fake viral posts—and calls out the fakers. He sees firsthand the “greed for virality” that may drive the impulse to propagate misinformation. It’s “overdosing on the euphoria that comes from seeing those like and retweet numbers rise into the thousands,” he says.

Getting a lot of likes and comments “gives us an immediate social reward,” says Erin Vogel, a social psychologist and postdoctoral fellow at Stanford University. In other words, they make us feel good. Studies have found that posting to social media gives one’s self-esteem a temporary boost.

The need to seek out things that make us feel good may be exacerbated right now, as people try to come to grips with a pandemic, a collapsing economy, and sudden isolation. “In times when we’re all really lonely, it’s tempting to hold onto that feeling, especially if we’re posting something that gives people a lot of hope,” says Vogel. The idea that animals and nature could actually flourish during this crisis “could help give us a sense of meaning and purpose—that we went through this for a reason,” she says.

It was the running theme of many of the viral tweets. “Nature just hit the reset button on us,” read a tweet celebrating the dolphins supposedly swimming in Venetian canals.

“I think people really want to believe in the power of nature to recover,” says Susan Clayton, a professor of psychology and environmental studies at the College of Wooster, in Ohio. “People hope that, no matter what we’ve done, nature is powerful enough to rise above it.” (Read about how this incredible—and real—shark photo went viral.)

About half of Americans say they’ve been exposed to made-up news or information related to coronavirus, according to a new Pew Research Center survey. While a fake happy news story about dolphins in a canal may not be all that problematic, relatively speaking, there can still be harm in spreading false hope in times of crisis.

These fake feel-good stories, Vogel says, can make people even more distrustful at a time when everyone already feels vulnerable. Finding out good news isn’t real “can be even more demoralizing than not hearing it at all.”

Spots of hope on social media are likely to play a key role in keeping spirits up in the weeks and months ahead, as people self-quarantine in their homes and connect with each other through screens. “I’d encourage people to share positive things,” says Vogel. “But it doesn’t have to be anything dramatic. It just has to be true.”