evidence confirms that common ancestry underlies all biological diversity, and later we
shall revisit the extent to which organisms actually are adapted to their surroundings.
Darwin and Wallace came by their insights in the course of direct exposure to nature.
Both men were widely read, boundlessly inquisitive, and steeped in Victorian traditions
of collecting and identifying organisms. Each puzzled long and hard over the origin of
species. The aristocratic Darwin, having passed on careers in the ministry and medi-
cine, used family connections to arrange a five-year trip around the world. His famous
voyage on the Beagle allowed the young naturalist to view similar geological strata in
widely different places, marvel over fossils of extinct creatures, and ponder peculiar-
ities of island life, most famously in the Galápagos Archipelago. He never again went
abroad, labored for more than twenty years on “one long argument” for selection, and
then anguished over prospects that a lesser-known biologist would steal his thunder.
Wallace could scarcely have been more different, born into the working class and
financing his travels primarily by selling specimens to museums and private collectors.
As a young man he spent four years in South America, briefly returned to England, and
embarked on eight more years of ieldwork that culminated in a classic topic, TheMalay
Archipelago. 1 Incessantly curious, unfazed by discomfort and disaster, he conceived of
natural selection during a malaria-induced stupor, announced his insight to Darwin in a
letter, and always deferred to the older man as chief architect of their theory. In modern
parlance, Darwin seems to have been obsessed with reaching the peak while Wallace
was at ease on his own path.
As a Missouri teenager with little knowledge of Darwin and none of Wallace, I
scoured the countryside for animals. Inspired by Roger Conant's FieldGuidetoReptiles
and Amphibians, eager for wilder times in wilder places, I also daydreamed about par-
ticular species that caught my eye. 2 Texas alligator lizards, for example, were first
discovered in the Devil's River country and named Gerrhonotus infernalis in 1858 by
the Smithsonian's Spencer Fullerton Baird, but a century later, when I encountered
them in topics, there was still almost nothing known about those snaky, bright-eyed
creatures. 3 Imagining myself a trailblazing naturalist, I pored over accounts in Hobart
Smith's Handbook of Lizards of closely related West Coast species—especially quotes
from Henry Fitch, who deemed them unusually intelligent and reported a southern al-
ligator lizard holding off three yellow-billed magpies by hissing and threatening with
open jaws, tail curled forward like a shield. 4
Maybe, I thought, I'll roam the Rio Grande borderlands someday and learn
something equally exciting about Gerrhonotus infernalis!
Fitch was among the “influential saurologists” profiled in Handbook of Lizards, and
a photo of him caught my attention. The other men (and one woman) were obviously
posing, but he wore a straight-brimmed World War I cavalry hat and looked intense,
as if distracted from an important task. Publications in our local college library gave a
University of Kansas address, so in 1962 I wrote him announcing my upcoming herpet-
ological career and asking about fieldwork that I planned to conduct in Texas. However
pretentious my letter, within a couple of weeks back came Henry's cordial, handwritten
explanation of how to determine an alligator lizard's sex: “By grasping the base of the
tail, twisting it very slightly, and exerting slight pressure with the thumb on one side,
ventrally, one usually can cause a hemipenis to be momentarily exposed. Or failing in
several such attempts, one may be reasonably sure that the specimen is a female.”