Biology Reference
In-Depth Information
it relate to individual ecology? Finally, how did it evolve over geological time? Although
the ethologists' vision was explicitly comprehensive, they emphasized instinctive beha-
viors—those that first appear “full-blown,” with no learning involved—and they stressed
assembling a detailed behavioral inventory, called an ethogram, prior to conducting ex-
periments. Lorenz himself had trained in comparative anatomy, and early on he studied
how behavior originated and changed during the evolutionary diversification of ducks
and geese.
Tinbergen's digger wasps, von Frisch's dancing bees, and Lorenz's water fowl were
on my mind while I wrote up the European museum project on snake tail injuries and
delved more deeply into ethology. Baylor University's Frederick Gehlbach had just pub-
to chat about our mutual interests. As the visit ended Fred offered me a live Texas
coralsnake, and having never kept cobra relatives, I welcomed a chance to observe
the thirty-inch-long gem. Back at U.T.A. my captive crawled under moss in its terrari-
um, resurfaced, and then attentively followed the invisible path of a rough earthsnake
I'd dropped in as food. The earthsnake succumbed within minutes of being bitten,
whereupon the larger serpent, after deliberately walking its jaws along the prey, con-
sumed it headfirst.
That evening I read everything available on coralsnakes and prey trailing. Knowledge
of snake diets had mostly come from chance observations and by forcing animals to re-
gurgitate, but because snakes eat infrequently and their stomachs are usually empty,
those methods require the sort of long-term studies pioneered by Fitch. Lugging journ-
als to my library carrel, I sifted through a century of
Zoological Record
and lingered
midt even identified a new species of burrowing serpent among their prey, but evidently
no one had followed his lead and really tapped into museum specimens—accumulated
by many collectors over the course of decades—to conduct a detailed study of a single
snake species' diet over its entire range.
10
Around midnight I charged back to the biology building and down into the ever-grow-
ing Collection of Vertebrates, where I pulled out several jars of pickled coralsnakes.
Then I carefully slit each one's belly, as I'd done as a teenager with the skinks at K.U.
and massasaugas in Fort Worth. Although the first few coralsnake stomachs were empty,
within the next couple of dozen were several food items. Prey were often partly di-
gested, but by comparing remnants with intact specimens of all potential species, I
identified them, determined sex, and estimated length and mass. Clearly I was on to
something. Preserved coralsnakes without prey required only a few minutes to process,
but those containing their last meals took half an hour, and I barely finished in time for
my own breakfast. That same morning I asked Bill about changing my thesis topic to
coralsnake feeding, and with his enthusiastic approval I set about visiting other collec-
tions and accumulating more live animals.
encouraged me to modify his research setup so as to examine coralsnake hunting tac-
tics: a few field observations suggested that they actively forage, and I was to test the
hypothesis that they used chemical cues to find food. Prior to each experiment I encour-
aged a prey snake to crawl around an octagonal alley, its movements limited by card-
board walls on a cloth substrate that was washed between trials. As predicted, a hungry
