Strings of eggs from breeding pairs of the Houston toad at the Fort Worth Zoo are prepared for release into a pond at Griffith League Ranch. Each bag of eggs is filled with local pond water to acclimatize them to temperature and water quality and then emptied into floating bags that will help protect the eggs as they develop into tadpoles. | Julia Robinson for Vox

Love — or at least sex — was in the air of the small, windowless, biosecure room at the Fort Worth Zoo in Texas. Sixteen rectangular, clear plastic bins lined the room’s back and side walls, tiny stages for unlikely romances.

Each bin contained a plastic green pond plant — the kind you would buy for fish to make Nemo feel at home — about an inch of water, and two endangered Houston toads, a drab-looking critter with a pale belly, dark spots, and raised patches of skin that, in a betrayal of the stereotypes, aren’t warts.

It was a Wednesday afternoon over the spring, and Allison Julien, the zoo’s reproductive science biologist, prepped 16 syringes to inject hormones into the croaking male toads to help, well, get them in the mood. The females, hanging out in their respective bins, had already been injected with their doses since it takes them longer to both lay eggs and acquiesce to the next step.

Soon, each female shuffled around her tub, laying a string of thousands of tiny eggs strung together like black pearls. A male clung to her back, his legs wrapped around her body and his little toes mashed to her belly as — and sorry to get graphic here — he peed on her eggs; for this species, sperm is released in their urine. The fake vegetation helped the egg strands spread out to maximize fertilization. And I like to think…might have even helped a little with the ambiance.

You probably haven’t thought much about amphibian-assisted reproduction lately (or, let’s be honest, ever). But in a lab tucked inside the Fort Worth Zoo, scientists are playing matchmaker for one of the rarest toads in the country — performing ultrasounds, injecting hormones, counting eggs by the tens of thousands, and trying to keep a species alive with spreadsheets and syringes.

The Houston toad, once common across southeast Texas, is now so endangered that its best shot at survival involves assisted reproduction, willing landowners, and some very determined humans who want to help them survive again in the wild.

It’s weird, hopeful, kind of beautiful — and it just might be working.

Melanie Pavlas, executive director of the Pines and Prairies Land Trust, gives a tour of restoration efforts at the 302-acre Yegua Knobbs Preserve in McDade, Texas, where mechanical mulching of yaupon and controlled burns have reopened the landscape to native plants. Pine trees show char marks from a previous controlled burn on the property.

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How the Houston toad got pushed so close to the brink

The Houston toad was first identified in the 1940s near an old airfield base in southeast Houston, where crashed planes from World War I military exercises littered the ground.

After that initial discovery, herpetologists made sporadic observations of hundreds of toads at individual ponds, on coastal plains, and in forests across 13 Texas counties, but their sightings were still relatively few and far between.

A red pipevine swallowtail caterpillar feeds on Louisiana vetch at the Yegua Knobbs Preserve in McDade, Texas. Controlled burns help native grasses and wildflowers to rebound.

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“The challenge is [the Houston toad has] always been kind of rare,” said Paul Crump, the state herpetologist for Texas Parks and Wildlife, who has worked for nearly two decades on Houston toad recovery. “And we’ve only got these little glimpses into what it’s doing.”

All the while, Houston toad numbers were declining, and declining fast.

By the mid-century, people in the state had introduced non-native species like fire ants that bit and killed juvenile toads, feral hogs that ate them and reduced wetland water quality, and grasses that made it difficult for toads to navigate. Meanwhile, Texas was expanding fast into Houston toad habitat — turning forests and savannahs into farmland, houses and suburban subdivisions, shopping centers and parking lots.

The toad needed help, and so in 1969, it was included in the Endangered Species Conservation Act, the precursor to the 1973 Endangered Species Act, making the Houston toad one of the first federally protected amphibians in the country.

But the listing may have been too late. In the years since, the Houston toad has likely declined more than 90 percent.

The Houston toad isn’t among the class of iconic megafauna like grizzly bears or wolves. It doesn’t grace national emblems like the golden eagle or put food on our tables like Canada geese. But uncharismatic species like the Houston toad still matter.

Paul Crump listens to bird and frog calls at the Yegua Knobbs Preserve in McDade, Texas.

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