(left to right): © ROB PERRYMAN; AARON ONTIVEROZ/THE DENVER POST VIA GETTY IMAGES; AP PHOTO/DESMOND BOYLAN

Top stories: Manta ray ‘friendships,’ preventing suicide, and a hidden hotbed of Zika

These manta rays form ‘friendships’ that last longer than a summer fling

Although many sharks are solitary creatures, their manta ray relatives are surprisingly social: They copy one another’s movements, play together, and will even curiously approach nearby humans. Now, scientists have discovered they also form “friendships” with their fellow rays—loose associations that can last for weeks or months at a time.

Three suicide prevention strategies show real promise. How can they reach more people?

Many paths in life can bring someone to the brink of suicide, and a shorter phone number might seem to be a naïvely simple solution. But researchers have repeatedly found three strategies that seem to help: suicide hotlines, standardizing mental health care, and banning access to lethal means like guns and pesticides. That’s especially important as the rate of suicide in the United States has surged 33% since 1999.

Infected travelers reveal Cuba’s ‘hidden’ Zika outbreak

As Zika virus raced through the Americas and the Caribbean in 2015 and 2016, it infected an estimated 800,000 people and left nearly 4000 newborns with serious brain damage. But by mid-2017, the virus had all but disappeared from the region—or so it seemed. A new analysis of Zika-infected travelers who returned to the United States or Europe in 2017 or 2018 has found that 98% had visited Cuba, which did not report any cases to world health officials at the time the country’s outbreak apparently peaked.

Century-old salmon-smeared notebooks reveal past bounty of fisheries

Finding a bunch of old notebooks covered in dried-up fish slime may not be most people’s idea of a treat. But when Skip McKinnell, then a fisheries consultant with Canada’s Department of Fisheries and Oceans, discovered dozens of such notebooks in a university closet in Vancouver in 1996, he was ecstatic about the information he might be able to glean about long-dead populations of sockeye salmon.

Here’s what Earth might look like to aliens

When Earthly astronomers train their telescopes on exoplanets beyond our solar system, they’re lucky to see even a single dot of light. How can they figure out whether it might have suitable conditions for life? To find out how they might know more, a team of scientists turned the problem on its head: They took images of a habitable planet—Earth—and transformed them into something alien astronomers light-years away would see.