The unexpected stars of the summer TV season are the animals whose dramatic and moving stories of survival have made Discovery’s “Serengeti” documentary series, narrated by actress Lupita Nyong’o, one of the year’s must-see highlights.

There’s Shani, the gorgeous zebra who protected her foal from being devoured by crocodiles as one herd after another crossed a treacherous river only to see it swept away by the fast-moving current.

There’s Bakari the baboon. Isolated in a power play by the leader of his tribe, he came through in the clutch when a baby baboon was trapped in a treetop and delivered it to safety while a fire raged across the plains.

The struggle of rejected lioness Kali to keep her cubs alive as a trio of black-maned lions stalked them has been a nail-biter.

Viewers have taken to Twitter to declare how the six-episode series (8 p.m Sunday) has moved them. After Sunday night’s episode, which truly illustrated the phrase “survival of the fittest,” Murphy @spankdumb wrote: “What did Kali do that was so bad that the rest of the pride is hating on her? Her kids are getting eaten by the black manes and y’all petty asses still slut-shaming a single mom trying to live her best life.”

The intimacy established between viewers and animals is the result of some virtuoso camera work by producer John Downer and his team, which includes cinematographer Matthew Goodman and Geoffrey Bell, a camera specialist, and a driver and a guide. Of the several cameras used, the one that gives incredible close-ups of the wild animals is the so-called remote-controlled lion-proof camera.

“It’s covered with very strong fiberglass that’s thick enough so that not even a lion can break it,” Downer tells The Post. “We also call it a boulder cam. It’s rounded for a reason. A lion can’t get its teeth into it.”

Or, as Bell explains in a behind-the-scenes video clip on the show’s website, “The lions don’t recognize it as skin or meat.”

Eventually, the lions and other animals ignore the tawny-colored camera, enabling the crew to capture intimate moments and allow Downer and his team to build the individual story arcs while they filmed over a two-year period. Naturally, the unexpected moments were those that made it into the show.

“We chose storylines that would have legs,” Downer says, telling them from a perspective audiences could relate to: “The story of Tembo, the elephant who leaves his family to find his place in the world, that’s never been told.” It’s common for male elephants to split off when they are 15 or 16 years old, he says. “They don’t really like it. It’s tough going out with all the problems in the world. That was an obvious story to follow.”

The star animals fortunately have made it through the four episodes that have aired thus far, averaging over 2 million viewers a week and putting “Serengeti” on track to be Discovery’s most-watched documentary since 2013.

Shani found her foal, who collapsed from exhaustion and malnutrition, as vultures circled overhead. “It was only a couple of days [that they’d been apart], but it’s a long time without protection from the mother,” Downer says. “The foal was desperately looking [for a herd]. It didn’t want to be alone. That’s the most dangerous thing.”

With a Season 2 renewal expected soon, Downer appreciates that viewers have made “emotional connections” with the animals. “We see how close we are to the animals and have an understanding that’s deeper when you realize the complexity of their lives,” he says.