Issue 15.5: October/November 2012

The Tortoise and the Dare

Story by Julia Steele

Photos by Elyse Butler

 

As David Burney and Lida Pigott Burney are well aware, necessity is the mother of invention. Add to that the maxims “Everything old is new again” and “Slow but steady wins the race,” and you get an inkling of why giant tortoises are now roaming a remote corner of Kaua‘i. The innovative Burneys, who between them have seven decades of scientific study in places as far-flung as Kenya and the Mascarene Islands, seven years ago began planting a six-acre plot near Makauwahi Cave, Kaua‘i with native species. The Burneys sought to create a large stock of rare and endangered Hawaiian plants — eighty-three species in all—in the hope of making those plants less rare and endangered. They planted six thousand baby natives, among them kou, ma‘o, koki‘o and lama, and nurtured them fastidiously.

 

Things have gone extraordinarily well —tiny seedlings have become twelvefoot- tall trees — but along with the thriving things the Burneys wanted came thriving things they didn’t: weeds. So out came the mowers and weed-whackers — and with them a nasty carbon footprint and a constant need for labor.

 

David Burney knew that in the past— in the far distant past, say around the time that man started walking upright — none of these weeds existed in Hawai‘i. Back then, rather than being choked out, Hawaiian plants were more at risk of being nibbled up by the giant flightless geese and ducks that roamed the Islands. To thwart the birds, the plants developed ingenious defenses. Conventional wisdom holds that native Hawaiian plants are delicate, vulnerable beings that evolved without defenses, but that’s not so, says David. What they did was evolve without defenses against mammals. Things with beaks were a different story. For millions of years Hawai‘i was a paradise of birds, and to fend them off, plants evolved fancy tricks like divaricating, wherein a plant splits its branches immediately after coming out of the ground, then splits them again and again and again to model itself into something akin to a bird’s nest. The plant becomes all but impenetrable, and any large creature reaching in to pluck leaves with a beak won’t get far. (Any creature with teeth, of course, can just munch right through.) Native plants had other defenses, too, which included growing a flexible trunk that couldn’t be snapped to the ground and tingeing leaves with a purple pigment that’s hard on the kidneys of birds and reptiles. For eons a symbiosis existed between Hawai‘i’s plants and birds, and everything thrived. 

 


 

With the coming of mammals— humans, rats, dogs and pigs—that finely tuned balance was thrown into disarray. In the centuries that followed, almost all of the native birds were wiped out. Successive waves of migrants brought more plant and animal introductions—deliberately or inadvertently—which is how the hated weeds arrived. With ample sun and rain and nothing to keep them in check, they ravaged the landscape, laying waste to the native plants.

 

And that’s where the invention part of this story comes in. The Burneys knew from their time in the Mascarene Islands that there was one creature that had consistently populated remote islands in huge numbers: the giant tortoise. Over the course of its two hundred million years of existence, it had in fact populated almost the entire world, but on islands—where it had virtually no foes—it really prospered. Its shell made a wonderful boat, and it could go without food or water for six months, so ocean crossings were none too troublesome. One of the few island groups the tortoises never colonized was the world’s most remote: Hawai‘i.

 

As Homo sapiens evolved and moved out into the world, most giant tortoises went the way of Hawai‘i’s native birds. A tortoise’s tough shell may have made a great makeshift boat and a terrific defense against dinosaur teeth and lion claws, but in the hands of humans it functioned as a convenient cooking pot. Tortoises were easy to catch, easy to kill and easy to cook —flip upside down and roast over the fire —and whenever humans arrived on the scene, tortoises swiftly went extinct. By the nineteenth century most were gone, with only a few holdouts surviving in places where prehistoric man never really moved in, like the Galápagos and the Seychelles atoll of Aldabra.

 

On a visit to a massive native plant restoration project on the Mascarene island of Rodrigues last year, the Burneys discovered to their delight that giant tortoises there were being used as all-natural weedwhackers. Scientists in Rodrigues had fenced off a forty-seven-acre plot, planted 160,000 native plants and let loose a thousand tortoises among them. The tortoises, conditioned by millions of years of evolution, ate the invasives and avoided the natives. The entire project was prospering — and the tortoises were doing all of the work. Could something like that work on Kaua‘i? the Burneys wondered. Would the tortoises—which also have a beak— fill the role of Hawai‘i’s now-extinct giant birds and eat our weeds while avoiding our natives?

 

It was a daring proposition. “The thing that really sold me on the idea that it might work was that they had three kinds of native Hawaiian plants inside the Rodrigues’ restoration area, and the tortoises wouldn’t eat them,” says David. “It made me think, ‘Gee, there must be some sort of connection. Plants native to remote islands are somehow defended against these animals.’” The Burneys couldn’t pull off a Jurassic Park feat and bring back Hawai‘i’s extinct birds, but maybe they’d hit on a close-to-perfect substitute. That proposition, though, begged an immediate question: Where would the tortoises come from?

 


 

Turns out they’re already here. Young tortoises are now favored reptiles in the pet trade, and in the Islands people buy them in local pet stores, turning a blind eye to the fact that their baseball-size companions will grow to weigh some two hundred pounds and undoubtedly outlast them. Jim Juvik is a professor of geography and environmental studies at the University of Hawai‘i at Hilo who has worked all over the world on tortoise issues. He is also a tortoise savior of sorts, who adopts Hawai‘i tortoises that people no longer want — say, when the kids go off to college and the aging parents have no interest in dealing with a lumbering behemoth in the backyard. With Juvik’s help, the Burneys were able to find eight tortoises from Maui, O‘ahu, the Big Island and Kaua‘i—six African spurred tortoises and two leopard tortoises—whose owners were ready to give them up.

 

Today those eight wander the Burneys’ native plant sanctuary, which is set on land leased from Grove Farm, and the Burneys’ dream has come true: The tortoises eat the weeds and avoid the natives. Mechanized weed-whackers are a thing of the past. Roam through the fenced acres of the Burneys’ plant project and you come upon the eight: dusty, stolid, imperturbable, improbable. There is Chel, who has the number “1” painted on the back of his shell—an identifying license plate, though because he is the largest of the Makauwahi tortoises at 175 pounds, he’s pretty easy to identify without it. Chel is named after Chelychelynechen quassus, the now-extinct turtle-jawed moa nalo, a giant duck that once roamed Kaua‘i. Among Chel’s compatriots are Tham, named after Thambetochen chauliodous, a genus of extinct giant ducks from Maui; Pretty Boy, a ten-yearold tortoise named for his gorgeous gold, black and brown shell; and Bamm-Bamm, a young male who is by far the most aggressive of the eight: He is constantly picking —and losing—fights with the older, larger tortoises and will try to mate with anything, even a water dish.

 

The Burneys are obviously enamored of their octet. “What it boils down to is they have personalities,” says David. “They each have individual characteristics and they are really quite charming. Everything gets kinda peaceful when you watch tortoises. It slows your heart rate.”

 

The eight antiquities spend their days munching through pound after pound of the invasives that make gardeners and botanists in Hawai‘i blanch—Guinea grass, nut sedge, haole koa, maunaloa—leaving the flourishing natives around them untouched. And as they do, the Burneys continue to make other valuable discoveries. Tortoise dung, for example, makes excellent compost. And seeds of native plants that pass through the gut of a tortoise germinate much more readily than those that don’t: It takes two weeks for anything to pass through a tortoise’s digestive system, and seeds that pass through emerge scarified and much more likely to sprout.

 

David Burney does caution everyone about trying this at home: Both he and Juvik counsel that adopting a tortoise is not an act to be taken lightly. After all, notes David, when Charles Darwin wrote the governor of Mauritius in 1874 and urged him to repatriate giant tortoises on the surrounding islands, the governor dispatched an expedition that did just that, reintroducing tortoises to islands where they had gone extinct and creating a modern safe haven for them. Today there is an apocryphal tale that one of those tortoises was named Darwin in honor of the great scientist—and almost 150 years later, the animal is still alive. Unverifiable maybe but quite plausible: The oldest giant tortoise on record lived for 255 years. Point being, say David and Juvik, your tortoise will not only likely outgrow you, it will likely outlive you, too. Tortoises are also wont to wander off, and while their most famous characteristic may be their lead-footed pace, they are noted too for their steadiness: Darwin estimated a giant tortoise could cover as much as four miles a day.

 

As for any concerns about a wild tortoise population explosion on Kaua‘i, though, the Burneys say forget it. Their tortoises all live within a securely fenced area, and even more to the point, says David, is the fact that all of the tortoises living at this “monastery,” as he calls it, are males. 

 

To learn more and find out about visiting the Burneys’ project, visit www.cavereserve.org.