How can we know that the continents were all once joined in one big supercontinent eons ago? Why, thanks to the blind cave fish, of course.

Such informational oddities are embedded deep within Extreme Creatures: Life at the Limits, on view at the Witte Museum through Sept. 6, in an exhibit that explores the far reaches of reality all around us, if not readily visible.

That fishes living in caves are blind reveals the process of adaptation to nature’s norms, many of which might seem extreme to humans. Ancient people lived in caves, too, but they had the light of bonfires to radiate warmth and allow sight. Fishes have no such luxuries, instead able to thrive in near-freezing cold and utter darkness thanks to the process of natural selection.

One Extreme Creatures placard explains that through DNA analysis, scientists have determined that Australian blind cave fish and Madagascar blind cave fish are more closely related than any other groups on the planet, despite thousands of miles of ocean between them.

“Hundreds of millions of years ago, the future Madagascar and the future Australia were part of the same landmass, Gondwana,” the placard reads, and the two fish species have never lost their close connection.

Blind cavefish are but one among thousands of species represented in Extreme Creatures, which delights in the vast array of natural oddities to be found at Earth’s harshest edges.

Penguins, beetles, corals, corpse flowers, moths, mushrooms, whales, woodpeckers, sawfish, electric eels, kiwis, kangaroos, and something called the black swallower all figure into the exhibit, displaying their tendencies of strength, speed, sight, scent, and strangeness.

Did you know a scallop has 100 eyes? Or that green algae can see?

“This exhibit is so cool,” said Witte President and CEO Marise McDermott, telling how her 3-year-old grandson fell asleep clutching his little stuffed tardigrade. A giant, 8-foot fiberglass version of the microscopic creature greets visitors at the entrance of the exhibit, essentially a mascot for animal extremity.

The tardigrade, or “water bear,” as it is commonly called, figured prominently in Neil deGrasse Tyson’s 2017 Cosmic Collisions talk at the Tobin Center for the Performing Arts. “The universe is trying to kill you,” Tyson declared, holding up the tardigrade as the hardiest survivor of all.

Upon entry, an enlarged model of the tardigrade greets visitors to Extreme Creatures: Life at the Limits. Credit: Scott Ball / San Antonio Report

Tardigrades are admired for their ability to survive extremes even beyond the atmosphere. They are known to withstand temperatures as cold as the surface of Pluto (nearly -400 degrees) and water pressure six times as much as the deepest ocean (about 16,000 pounds per square inch), and can live a decade without a trace of water.

The bess beetle is no less strange, though for different reasons. The little black beetle is among an array of Texas creatures added to the show, which originated at the American Museum of Natural History, by Helen Holdsworth, a naturalist and the Witte’s director of engagement.

A placard explaining the presence of the bess beetle reads, “Sometimes the unexpected wonders of the natural world are … kind of gross,” going on to explain that in order to maintain nutrition, the beetle eats its own poop, and also lays its eggs in it for the newborns to feed on.

The Mexican free-tailed bat makes an appearance, alongside a Texas blind salamander and a toothless blindcat suckerfish, both found in the deeps of the Edwards Aquifer. A scorpion from Holdsworth’s own yard is also in the exhibit, viewable in its little windowbox with the aid of infrared light that renders it an otherworldly green glow.

Holdsworth’s initial interest in the natural world began with what at first seems to be a decidedly less weird animal among the freakish flora and fauna of Extreme Creatures.

“It was really just the whitetail deer,” she said, having grown up in the Hill Country. “Most people wouldn’t think it unusual or, you know, particularly fascinating. … But they have some great adaptations that they use to survive. ”

For example, fawns have no scent and can lay still in tall grass for an entire day while their parents are off foraging. The young deer are thus largely protected from predators, who can’t see or smell them. Deer also have no clavicles, which allows them to squeeze through tight forest spaces when making their escapes.

“They’re just really magical creatures,” she said.

Holdsworth’s revelation that even common creatures can seem strange if you look hard enough resonates with the discovery of Erpobdella mestrovi, the cave leech found 4,700 feet beneath the earth in the Lukina Jama-Trojama cave system in Croatia. That scientists would even climb so far down just to see what might be there is testament to the work that went into the exhibits of Extreme Creatures.

The show also points out how resilient humans can be, McDermott said.

“Especially with COVID, it’s so relevant to think about a species overcoming adversity,” she said. “Humans are amazing at adapting. But it really took us down. It was hard. This exhibit is so enlightening about how creatures over millions … of years have adapted to stress.”

Extreme Creatures: Life at the Limits is accessible with timed $5 tickets in addition to regular museum admission of $14. Free Tuesdays allow access to regular museum exhibits at no cost from 3-7 p.m., with an additional fee to see the special exhibit. Check the Witte website in advance of your visit for current COVID-19 safety protocols.

Senior Reporter Nicholas Frank moved from Milwaukee to San Antonio following a 2017 Artpace residency. Prior to that he taught college fine arts, curated a university contemporary art program, toured with...