Its eyes two ghostly white spheres, a slim deer stands in the middle of the nighttime photo, serenely munching a branch. In the next picture, a coyote inspects the camera, its nose huge like that of a pet dog sniffing an iPhone. Then come fuzzy cottontail rabbits and a scraggly possum. Taken in April by trailside cameras, the black and white pictures are—in their low-res way—historic. They are the first official recordings of animals using the largest wildlife crossing in the United States: the new Robert L. B. Tobin Land Bridge on San Antonio’s North Side. Measuring some 150 feet in both length and width, the structure arches gently over the traffic on the six-lane Wurzbach Parkway below. The final portion of the bridge opened to considerable media acclaim in April, with the express purpose of joining the two sides of Phil Hardberger Park and providing a safe passage for both the people and the countless wild animals that pass through its 330 wooded acres.

On an early summer ramble through the park by golf cart and on foot, San Antonio Parks and Recreation naturalist Casey Cowan points out some of the many amenities that make the large preserve a popular destination for human visitors, more than a thousand of whom may stop by on a busy day. “Here we have some water features,” she says, indicating small ponds rimmed by stones where animals come to drink. “I’ve seen birds and a herd of white-tailed deer using them.” A few steps away, she points to two attractive iron screens with rusty patinas: “These wildlife blinds were designed by local artists.” Each blind lets parkgoers spy on the area’s furry and feathered residents. Farther along the trails, motion-triggered cameras quietly click, which is how Cowan discovered earlier this year that the park’s deer were up to no good. “They were standing on their hind legs and eating our brand-new sumac trees!” she exclaims. Those trees, along with numerous other native shrubs and grasses, have been so carefully placed that the bridge looks completely natural. Many of the hikers, birders, and school groups strolling its broad expanse don’t even realize they’re on a highway overpass until they walk to the fencing on either side and look down. As for the critters, judging by their activity, they like it just fine.

A white-tailed deer snacks on the landscaping of the Robert L. B. Tobin Land Bridge in San Antonio at 2:09 a.m. on April 13, 2021.Courtesy of Phil Hardberger Park Conservancy

Meanwhile, a little less than three hundred miles away in South Texas’s steamy Rio Grande Valley, a very different type of wildlife crossing has also been receiving media attention. On January 25, an automated camera snapped pictures of a smallish spotted cat entering an underpass below Farm-to-Market Road 106, not far from Laguna Atascosa National Wildlife Refuge in Los Fresnos. The passage wasn’t much to look at—it’s a hundred-foot-long concrete culvert bordered by weeds—but it functioned exactly as intended, providing safe passage for area wildlife. Five-year-old Ocelot Male 331 (a.k.a. OM331) walked purposefully through the tunnel and exited on the other side. His GPS tracking collar identified him as one of a dwindling group: the only breeding population of ocelots on public land in the United States. Just over a hundred years ago, ocelots roamed South Texas (they are still numerous in Mexico, Central America, and South America). But after the Rio Grande Valley’s dense palm forests started to be cleared for agriculture around 1900, the number of cats declined, as habitat loss, fur trapping, and vehicle collisions took an unrelenting toll.

Today only some fifty to eighty ocelots remain in South Texas, roaming free but followed and studied by the U.S. Fish and Wildlife Service office at the refuge. Hilary Swarts, the wildlife biologist who coordinates the program, has been known to refer to her subjects as kitty cats, and worries more or less constantly about their most deadly enemy, the American automobile. “We had eight ocelots hit by vehicles in eleven months between 2015 and 2016,” she says, citing an especially bad year. “The phone ringing was my worst nightmare.” She has been sleeping better, though, following the completion in 2019 of eight new underpasses designed primarily to help keep the cats cross FM 106, which runs through their habitat. The wary ocelots took their sweet time checking things out, she says, but other animals stepped right up. “Bobcats, javelinas, tortoises, coyotes, long-tailed weasels, alligators—you name it, they’ve used the crossings,” says Swarts. “We’ve even seen shorebirds in them.”

The design of the structures is extremely basic. Each is a rectangular concrete tunnel sized for the road and the animals that are expected to use it. The one where the ocelot was photographed measured seven feet wide by seven feet high by one hundred feet long. The tunnels are accompanied by extensive chain-link fencing that cuts off access to the road and funnels the felines toward the passageways. In a final genius touch, any tunnels that might flood have raised catwalks. “Ocelots are great swimmers,” Swarts says, “but they don’t necessarily want to walk through a deep puddle with an alligator in it.” The simple design has another benefit: construction is economical. When completed together with other road improvements, culverts range from $38,000 to $200,000 (the ocelot-photo tunnel was $38,000). By contrast, the massive, landscaped, state-of-the-art Tobin Land Bridge cost $23 million. An even more extensive land bridge, scheduled for completion in Houston’s Memorial Park in 2022, will weigh in at $70 million. It is funded primarily by private philanthropy.

An ocelot emerges from the FM7 West tunnel at 7:03pm on February 18, 2021.
An ocelot emerges from a tunnel along Farm-to-Market Road 106 in February. No more than eighty of the animals remain in South Texas.TxDOT

As enthusiastic recent news coverage of both the Tobin and Valley critter pictures indicates, wildlife crossings are having a bit of a moment in Texas. The concept, however, is far from new. The idea started in France in the 1950s and spread across Europe, with countries like Germany and the Netherlands building large, attractive land bridges as a point of civic pride. But there is a dark truth behind wildlife crossings’ laudable installation: the appalling toll in life and limb exacted by highways in the first place. In the United States alone, according to the Federal Highway Administration, between 1 and 2 million animals are hit—and, for the most part, killed—by cars each year. Some 200 people in those cars die, and another 26,000 are hurt. These collisions also exact a steep financial toll, with the annual economic fallout for society estimated at close to $8.4 billion.

Over and above that, highways impose an environmental cost for animals in the form of fractured, disrupted habitat. When a road keeps creatures from reaching all parts of a once continuous range, they find it harder to hunt, feed, and raise young. Over the long haul, it can reduce a species’ genetic diversity and make it more vulnerable to changes in climate and other conditions. Simply put, pouring concrete and asphalt upsets the balance of nature.

As wildlife crossings have grown in popularity, some remarkable successes have been recorded. On one eleven-mile stretch of Colorado’s Highway 9, an average of 63 animal carcasses (mostly deer) were being found every winter. A system of five wildlife underpasses and two large overpasses—completed in 2016—resulted in a 90 percent carcass reduction. Banff National Park in Canada, which is famous worldwide for its early construction of 44 crossing structures, touted an 80 percent reduction in wildlife-vehicle collisions.

The success stories cited by advocates and reporters usually involve large hoofed animals, for the unfortunate reason that they cause serious damage in collisions (and are also easy to count). But big animals are by no means the most numerous wildlife crossing users, nor do they inspire the most ingenious designs. A quick YouTube search shows a plethora of species and animal crossing sizes. In a passageway in New Zealand for blue penguins, the birds vanish into what looks like a large drainpipe, while a bridge for red crabs on the Australian territory of Christmas Island employs screens to fit the crustaceans’ tiny, spiny feet. Over a highway between Melbourne and Sydney, rope ladders are navigated by squirrels, their tails flying high; and turtles follow each other into a shallow trough under a railroad in Japan. At the other end of the spectrum, one of the largest corridors is an underpass in Kenya for elephants. Predictably, YouTube viewers appeared delighted, leaving comments like, “Taxes going for something I’m OK with!” and “This makes me so happy : ).”

Texas, meanwhile, has quietly been in the wildlife crossing game for two decades. Only in the last five years or so, however, has the state substantially increased its efforts and profile. As far back as 2000, the Texas Department of Transportation was incorporating wildlife crossings—all of them underpasses—into selected road-building and repair projects. Those culverts were small and not usually monitored, so little is known about them. But starting in 2016, amid growing interest in crossings around the world, TxDOT picked up the pace. Today, spokesperson Adam Hammons wrote in an email, the state agency has completed 33 crossings and has another 23 in the planning stage, with the majority in South Texas. The crossings have been built mainly for ocelot protection and are associated with roadways large and small, from interstate highways and toll roads to a cemetery road. When asked which animals were using the crossings, Hammons confirmed the usual suspects—coyotes, deer, and rabbits—and added raccoons, bobcats, armadillos, tortoises, horned lizards, and indigo snakes, for a total of sixteen species in all, including, of course, ocelots. “The most unexpected animal,” he wrote, “was a mountain lion on SH 100.” Presumably that big cat had the crossing all to itself.

A cotton-tailed rabbit makes eye contact with a trailside camera on the Robert L. B. Tobin Land Bridge in San Antonio at 2:22am on April 15, 2021.
A cottontail rabbit looks at a trailside camera on the Robert L. B. Tobin Land Bridge in San Antonio at 2:22 a.m. on April 15, 2021. Courtesy of Phil Hardberger Park Conservancy
A coyote gets up close to a trailside camera on the Robert L. B. Tobin Land Bridge in San Antonio at 5:20am on April 19, 2021.
A coyote sniffs around the Robert L. B. Tobin Land Bridge in San Antonio at 5:20 a.m. on April 19, 2021. Courtesy of Phil Hardberger Park Conservancy

The number of non-TxDOT crossings around the state is small, because counties, cities, and state parks generally do not have the money to build their own. The one exception to that rule is San Antonio’s Tobin Land Bridge, which shows what can be done with visionary leadership and generous community support. The project goes back fourteen years, to 2007, when popular then-mayor Phil Hardberger spearheaded the acquisition of a large former dairy farm located less than thirty minutes from downtown—and thus perfect for a park. The only drawback was that the plot was split by Wurzbach Parkway, so something was obviously needed to connect the two sides. The city proposed a $13 million bond issue, which passed in 2017. Then, says Hardberger, “foolishly and with some hubris, I said I would raise the other ten million.” It took him a year, but he doesn’t regret it: “So many people have told me, ‘I feel better just being there,’” he says. The park and bridge “may be the most important things I did as mayor.”

In addition to saving human and animal lives, as well reducing medical costs and property damage, wildlife crossings also have long-lasting, indirect benefits. It’s true that no crossing can miraculously reunite a forest or prairie or valley that has been severed by a highway—that genie is out of the bottle. But they can help put some of the pieces back together. People who work with them every day confirm the long-term benefits. “In a small, local way we are increasing genetic diversity,” says Casey Cowan at Phil Hardberger Park, because the animals can safely move from one side of the park to the other, “helping rebalance the ecosystem.” In the Rio Grande Valley, Hilary Swarts is thankful that the ocelot program has received much-needed help. “Most [visitors] come away thinking underpasses are cool,” she says. “They dig it—Texans love their wildlife.”

Both the naturalist and the biologist are encouraged by the growing profile of wildlife crossings in Texas. But they are even more excited by recent congressional action. Two major bills are now in play that could give wildlife corridors a huge boost. Passed in the U.S. House of Representatives in July, a mega-infrastructure bill titled the INVEST in America Act includes up to $500 million in building and research grants for wildlife crossings over five years. A Senate counterpart, the Surface Transportation Reauthorization Act, pegs the amount at $350 million; it awaits a full-chamber vote. The outcome is far from certain—the two bills would need to be reconciled, and previous efforts have fallen by the wayside. But the optimistic Swarts has a good feeling about the future of wildlife crossings: “I think we will see more of this in the future.”