"All the thoughts of a turtle are turtles,
and of a rabbit, rabbits."
—Ralph Waldo Emerson (1893)
Lewis and Clark must have seen a great many turtles along the rivers and streams they followed or crossed, and the hunters may have encountered a few more in the tributaries and uplands away from the rivers, but the two captains, as well as the other journalists, evidently gave them no more than a casual glance.
In lieu of Lewis's promised book on the expedition's results in natural history, Nicholas Biddle managed to assemble one long chapter (Chapter 25, 53 pages) on "Botany and Zoˆlogy" of Lewis's descriptive paragraphs. It consisted of 33 plants, 38 animals, 56 birds, 11 fish, 7 crustaceans, and just 4 reptiles—horned lizard, snail, garter snake, and rattlesnake—but not one turtle. It may be, as some writers have speculated, that the explorers didn't come across any turtles or tortoises that they hadn't seen back home.1
On the other hand, from a turn-of-the-century point of view, and considering the American public's thirst for the mystery and wonder of the unknown West, there was nothing about turtles and tortoises that imbued them with the nobility of an elk, the ferocity of a grizzly, the magnificence of a pronghorn—"they are all Keenly made, and is beautiful"—or the clarion call of a meadowlark. Their reputations are safely ensconced in their shells, and "all the thoughts of a turtle are turtles."
Taxonomically, turtles and tortoises belong to the class Reptilla (reptiles) and the order Testudines (turtles), sometimes termed Chelonia (from chelone, the Greek word for tortoise). The shells that enclose their bodies consist of two parts, the upper or dorsal (back) one called a carapace (possibly from the Latin word capa, "cape"), the lower or ventral (abdominal) one called a plastron (an Old French word denoting a breastplate of armor). The carapace is made of bony plates that are fused with the bones of the spine and rib cage. The plastron consists of plates called scutes, which in some species are hinged to enable the turtle to completely enclose its body for protection after retracting its most vulnerable members—neck, head, legs, and feet. The shell also is fire-resistant.
A Bale of Turtles2
The terms carapace and plastron were unknown to Lewis and Clark's generation; they entered the herpetologist's lexicon only during the second half of the 19th century. The science of herpetology—from a Greek word meaning "creeping thing" or reptile—slowly took root in the U.S. around the turn of the 19th century, from intellectual seedlings that had recently sprouted in Europe. The name itself first appeared in print during the 1730s as herpetography, "a Description of creeping Things," according to the Oxford English Dictionary. Noah Webster, in his Compendious Dictionary of the English Language, published in 1806, defined tortoise merely as "a genus of amphibious reptiles, covered with a crust," and gave almost the same definition 22 years later in his two-volume American Dictionary of the English Language.
The science of herpetology expanded considerably in depth and scope toward the latter part of the century, and especially during the 1900s, including a great deal of popular interest in sea-turtles owing no doubt to their relatively large size—up to 450 pounds—and their photogenic qualities. Nevertheless, much remains to be learned about Testudines of every species. For instance, although nearly all turtles "bask," little is known about either the causes or the benefits of that conduct. Similarly, much remains to be learned about turtles' aural sense, which seems to be limited to low-frequency vibrations such as boat noises in water or footsteps on land. They lack external ear openings, but have scale-covered eardrums surrounded by bony boxes called otic capsules.
The average swimming speed for most turtles is 10 to 12 miles per hour, and at least one of the larger among the world's 300 species of turtles is capable of streaking through the ocean at a blazing 22 mph. On land, soft-shell turtles are comparatively sprightly in the short run, and some tortoises can sprint at the average walking rate of a human, but most amble along at a much more relaxed pace—say, between .13 and .30 mph, or roughly one city block in an hour.9
That brings up another story. Even though their respective carapaces and plastrons are quite light, the short legs, large feet, and broadly extended stance with toes pointed outward (like those of all footed reptiles), combined with their comparatively slow and deliberate pace, give them the appearance of laboring under a great weight, which may have been the inspiration for the ancient legends among many cultures that their lands were supported on the back of a huge turtle.10
1. See Keith R. Benson, "Herpetology on the Lewis and Clark Expedition: 1804-1806," Herpetological Review 3 (1978): 87—91.
2. Once the expression for a group of turtles, from a 15th-century Book of Venery, a gentleman's guide to hunting and the good life. James Lipton, An Exaltation of Larks (New York: Viking, 1991), 62.
3. "Diamondback Terrapin," in Chesapeake Bay Program, http://www.chesapeakebay.net/info/diamondback_terrapin.cfm. Accessed December 1, 2006.
4. The original description of this species was written in 1793 by the German botanist and zoologist Johann David Schoepf (1742-1800), from a type specimen sent to him by the Reverend Gotthilf Ernst (1753-1815), of Lancaster, Pennsylvania. In 1844 It was reassigned to the genus Malaclemys by the eminent American naturalist Asa Gray (1810-1888).
Ellin Beltz, Scientific and Common Names of the Reptiles and Amphibians of North America—Explained at http://ebeltz.net/herps/etymain.html. (Accessed December 7, 2006.) This is an extremely useful resource for students (and teachers) of herpetology. It includes translations of scientific names, common names, dates and authors of original descriptions, biographies, and mythological references. It covers salamanders, frogs and toads, turtles, alligators and crocodiles, lizards and snakes of America north of Mexico. It also explains that when the name and date following the binomial are in parenthesis, this signifies that the present genus is different from the genus in the original description.
5. Ronald Orenstein, Turtles, Tortoises and Terrapins: Survivors in Armor (Buffalo, New York: Firefly Books, 2001), 10.
6. This creek bed, which today dries up during the summer and fall, is in country that Clark, on the same date, described as "the Deserts of America,...as it is deficent in water, Timber & too Steep to be tilled."
7. Beltz, "Scientific and Common Names."
8. Around Lewis's time the official name of this species was Trionyx, meaning three claws.
9. Rachel Shweky, "Speed of a Turtle or Tortoise," in Glenn Elert, ed., The Physics Hypertextbook; An Encyclopedia of Scientific Essays, at http://hypertextbook.com/facts/1999/RachelShweky.shtml. Accessed December 3, 2006.
10. The rich history of turtles and tortoises in popular culture is outlined in Wikipedia at http://en.wikipedia.org/wiki/Turtles_and_tortoises_in_popular_culture. See also Gregory McNamee and Luis Alberto Urrea, A World of Turtles: A Literary Celebration (Boulder, Colorado: Johnson Books, 1997).
Funded in part by a grant from the National Park Service, Challenge-Cost Share Program.