long and two hundred pounds, big enough to kill unwary tourists. Meat-
eating lizards twenty times as heavy hunted in Australia in the recent
geological past (silhouette shows size of the extinct giant compared to a
modern Komodo Dragon).
odilians—several lacertilian families are equipped with modest na-
tatory skills and have shellfish-crunching batteries. Hunting shelled
prey in the Orinoco and other New World tropical rivers is the
clam cracker par excellence, the two-foot-long caiman lizard so
called because its deep tail and armor-studded hide recall the shape
of the local alligators known as caimans. Bulging jaw muscles and
nutcracker jaws make the caiman lizard nearly invincible in gus-
tatory confrontations with Amazonian mollusks.
Monitor lizards have not limited their guild membership to
the shellfish-eating clubs. On the Indonesian isle of Komodo is a
monitor that kills and eats goats, water buffalo, and German tour-
ists. The story of the Komodo dragon reads like the script for the
original King Kong (a carefully crafted movie with excellent dino-
saurs, molded by someone who read Al Romer's research paper).
Rumors of a great lizard living on a tiny island, a real-life dragon
called ora by the natives, reached explorers in the late nineteenth
century. Expeditions brought the first skins and bones to mu-
seums in 1912, and, for once, legend paled before reality. Up to
62 | THE CONQUERING COLD-BLOODS: A CONUNDRUM
eight feet long and as heavy as a lioness, the adult Komodo dragon
brandishes steak-knifelike teeth—sharp, recurved blades with ser-
rated cutting edges. Showing the same sagacity found in veteran
Nile crocodiles, fully adult dragons know their hunting territory
from years of experience. They know where to lie along hilly game
trails, awaiting the light footsteps of a deer. Attacks are instant
successes or failures because the ora has no stamina, and if it misses
on the first short rush, it has little sustained speed for a long pur-
suit. When attack succeeds, the cruel rows of slashing teeth cut
fearful wounds on the rump and thigh of ambushed animals and
the stricken prey may die of massive infection days later even if it
manages to break free from the dragon's mouth. Tethered live-
stock suffer truly terrible cuts across the legs when an ora slinks
into the compound under cover of the warm Indonesian nights.
Several humans, both natives and European visitors, have died in
savage daylight attacks. The victims simply had no warning sign
that the ora was waiting patiently a few feet from trail's edge.
Fearsome though the Komodo dragon is, we must go much
farther south, to mainland Australia, to find the full flowering of
monitor evolution. The great Australian island continent is a down-
under, topsy-turvy world in more ways than one. Instead of an in-
terlocking guild system of small, medium, and large predators, filled
mostly by mammals, such as we see in the Serengeti, the Austra-
lian predator guilds feature monitor lizards in many of the roles
we are accustomed to believe were reserved for the Mammalia.
The badger role is played well by Gould's monitor, a digging
predator specializing in buried prey. On other continents the
brotherhood of furry hunters—weasels, ferrets, and mongooses—
chase the small prey, but "down under" the long-bodied small
predators are pygmy monitors. Tourists in minibuses gawk at
leopards sleeping at midday in Kenyan game parks, but in the
Australian outback the traveling lizard watcher can catch a glimpse
of the seven-foot Perentie monitor, draped over a eucalyptus branch
to escape the noonday heat. Native Aussie mammals take a decid-
edly second place to monitors in the freshwater guilds, too.
The greatest lacertilian hunter of this region is, however,
missing today. A few thousand years ago a monitor Kong stalked
the Australian landscape: Megalania, a massive half-ton lizard
predator as big as a Kodiak bear. Fossil Megalania vertebrae and
MESOZOIC CLASS WARFARE: COLD-BLOODS VERSUS THE FABULOUS FURBALLS | 63
jaws with monstrous curved teeth were first discovered a century
ago by pioneering Aussie naturalists and now are known from sites
across Queensland, New South Wales, and Victoria. With the
eyewitness accounts of Komodo dragons in mind, one must sup-
press an involuntary shudder at the image of a resurrected thou-
sand-pound ora rushing out to tear apart the largest Australian
mammal.
64 | THE CONQUERING COLD-BLOODS: A CONUNDRUM
Dragons and half-ton monsters of Queensland's past should
not sway us into believing that the vast lizard species-empire was
built by brute force alone. Lizard adaptations include devices of
greater subtlety—body ornaments designed for fraud, intimida-
tion, display, and seduction. The Australian frilled lizard, one and
a half feet long at most, is of a typical lacertilian temperament, slow
to bite in earnest even when engaged in vigorous disputes over
territory or potential mates. There's evolutionary wisdom in such
restraint. Quarrelsome genes that give their owners a chip on the
shoulder will get weeded out of the population, if constant brawl-
ing leaves the lizard scarred, crippled, and too exhausted to breed.
Darwinian processes have operated on the frilled lizard to concen-
trate genes whose results are more theatrical than rowdy. Lining
Two-ton dragon lizard of
ancient Australia. Fifteen
feet long and as heavy as a
bull rhinoceros, the extinct
Megalania hunted giant
kangaroos during the
Pleistocene Epoch of the
Age of Mammals, a few
hundred thousand years
ago. A scaled-up version of
today's Komodo Dragon,
Megalania died out quite
recently, by geological
standards, and for reasons
that are totally unknown.
MESOZOIC CLASS WARFARE: COLD-BLOODS VERSUS THE FABULOUS FURBALLS
65
the lizard's mouth is tissue of the most brilliant vermilion. Hang-
ing limp around the neck is a wide collar of folded skin. When the
lizard must assert its presence, a direct biting attack is eschewed
in favor of a grand thespian display: the mouth pops wide open,
unveiling a sudden flash of red on palate and tongue, and the col-
lar snaps erect, spreading a scaly corona about the neck like the
frill around the Dutch Masters, increasing the apparent head size
sixfold. Hissing and lunging forward, the frilled lizard goes through
its act, a gaudy vaudevillian bit of behavior which transforms the
little inoffensive lizard into an animated trick-or-treat mask.
Body ornament for intimidation produces some of the most
decorative vertebral columns in lizardom. In most vertebrates the
vertebral spines are strictly utilitarian and nonornamental. The bony
prongs rise up from each vertebral segment to provide leverage
for the back and neck muscles (the series of bumps down your
back, between th
e shoulders, are the tops of vertebral spines). But
the Australian water lizard grows spines so long they project far
beyond the muscle contours and extend upward like a picket fence
embedded in a thin sheet of tough skin. This lizard's intimidation
technique, like that of most species, is broadside bluff. Turning
sideways to its foe, the water lizard puffs itself up, standing as tall
as possible, showing off its vertebral sail to best advantage, trying
to prove that it is bigger and nastier than its rival. If your rival
looks taller, then he might be bigger and stronger. This simple mes-
sage is encoded in most lacertilian brains and plays out automati-
cally during disputes, controlling the lizard's fight-or-flight response.
South American riverside forests are home for one of the best
broadside bluffers, the Jesus lizard. Here the males sport among
the most flamboyant vertebral crests known anywhere today. Sheets
of bone protrude from the head and the picket fence rises from
the torso to make the skinny lizard body look three times as big
as it really is. The name "Jesus lizard" doesn't come from the puff-
and-bluff display, but from the speedy getaway performed by the
lizard when its tiny brain snaps over to the flight mode. Very long
in the hind legs, the Jesus lizard can sprint so fast for a few dozen
yards that its momentum carries it across the surface of lake or
river, the long-toed strides propelling it far beyond the shore. After
its walk-on-water dash the lizard can sink out of sight, a bewilder-
ing performance for most enemies.
66 | THE CONQUERING COLD-BLOODS: A CONUNDRUM
Seventeen miles per hour lizard—
Crotaphytus. Up to a foot long, this
resident of our western deserts hits
top speed in a hind-legs-only
bipedal stride.
All today's cold-blooded speed records are held by lizards. The
best lacertilian sprinters are long-legged bipeds, species that at high
speed tuck their arms under the chest and stride on hindquarter
power alone. In our own American West the mountain boomer, a
short-bodied, wide-headed predator that gulps down big desert bugs
and other lizards, has been clocked at eighteen miles per hour.
Lizard feats of arms and legs span the entire range possible for a
land vertebrate, a complete evolutionary decathalon: burrowing by
wormlike amphisbaenid lizards; sand-swimming by Kalahari skinks;
snakelike grass-slithering by legless glass lizards; crocodilelike
swimming by monitors; leaf-leaping by anolis lizards (Florida cha-
meleons); claw-propelled digging; bipedal sprints; and the incred-
ible slow branch stalk by the Old World tree chameleons. And there
are even some lizards that can glide, using rib-supported wings.
Walking narrow branches is a tough high-wire act for most
lizards, difficult to master because the basic lacertilian posture is a
sprawl, with elbows and knees held far out beside the body and
the paws held far apart. Gripping a narrow branch is awkward with
such a wide-track gait. The prizes for the successful branch walker
are enticing: hordes of insects and other juicy prey teem among
the leaves, twigs, and stems. The Old World chameleons have
solved this problem with a suite of limb adaptations rarely matched
MESOZOIC CLASS WARFARE: COLD-BLOODS VERSUS THE FABULOUS FURBALLS | 67
elsewhere. Most lizards have broad chests, which separate left and
right shoulder sockets widely. Chameleons have deep chests, very
narrow from side to side, like that of a cat. So the chameleon arms
can swing fore and aft directly under the body. And the chame-
leon's forepaws can grip the narrowest of perches. Most lizard hands
are rather crude five-fingered devices incapable of a precise grip.
Chameleon hands are cleft—two fingers are separated from the
other three at the wrist—and the chameleon can use the two as a
sort of scaly thumb for gripping a branch. Hind limbs are similarly
cast into a narrow-striding, gripping mode. With four precision
grippers and a narrow stride, the true chameleon on the hunt makes
all the slender vines and branches of the tropical forest unsafe for
butterflies and beetles.
Our own mammalian order, the primates, prides itself on
hand—eye coordination; monkeys, apes, and man are all good ma-
nipulators. But no mammal can rival the chameleon for eye—tongue
coordination. The tongues of chameleons are explosive devices,
lying loaded on the floor of the mouth, ready to fire forward as
elongated, muscle-propelled missiles armed with a sticky, bug-
catching warhead. Missile warheads are useless without their guid-
68 I THE CONQUERING COLD-BLOODS: A CONUNDRUM
The Malay flying lizard,
Draco. About six inches long,
nose to tail tip.
ance systems, and the chameleon has a stereoscopic rangefinder
and fire-control apparatus unique among vertebrates. Each cha-
meleon eye is mounted in a scale-studded turret which can move
independently, scanning the branches for insect targets. Once a
beetle is located, eyes switch to attack mode—both turrets lock
their stare forward on the target. Eyes feed the brain target data,
distance, bearing, target size—the fire-control computations are
swiftly made, automatically, without conscious thought, zap!—the
tongue muscles contract, hurling the bony tongue base forward and
Best tongue show in lizarddom. Chameleons are
lingual sharpshooters, firing their extensile tongues
twice their body length to catch insects. This genus
is Microsaura, one of the smallest varieties, only a
few inches long head to hips. Other species reach a
foot or more.
squeezing the tongue warhead at great speed out of its contracted
state. Another Congolese beetle is swept into the high-tech cha-
meleon jaws.
Lizards labor under the disadvantage of being the least pub-
licized reptile clan, but their close kin the serpents bear the worst
prejudice handed out by human society. This is unjust. Snake
anatomy contains the most clever and intricately efficient feeding
apparatuses to be observed anywhere among land vertebrates. Our
human problem begins with our adaptive table manners; we're not
MESOZOIC CLASS WARFARE: COLD-BLOODS VERSUS THE FABULOUS FURBALLS | 69
accustomed to admiring creatures that can swallow something larger
than their heads. All human parents, from Boston mayors to
boomerang-wielding natives, warn their children not to stuff too
large a hunk of food in their mouths. Human gullets are small and
have only modest capacity for expansion. It's ecologically adaptive
for human parents to discourage gulping big pieces of food, be-
cause choking is an uncomfortably common agent of human mor-
tality.
Snakes, however, cannot chew. The evolutionary path they
chose early in their career required unusual adaptations for swal-
lowing huge hunks of food: (1) snakes are all predators, subsisting
mostly on live prey; (2) they ambush by stealth, not by moving
&n
bsp; about scanning for victims, hence snakes don't meet a lot of po-
tential prey each day; (3) therefore snakes have to make the most
of each opportunity and should attack the largest potential prey.
The Darwinian processes that favor the selection of big prey have
also equipped serpents with their special organs for throttling and
stabbing. Pythons have a crushing attack. They coil around large
victims, constricting whenever their prey exhales, suffocating it
slowly and with an economical expenditure of force. (Contrary to
popular myth, big constrictors don't crush bones and pulp their
victims into pudding; just enough force to asphyxiate seems to be
the rule.) The poison attack evolved by several other snake fami-
lies allows them to inject their venom with surgical precision
through hollow fangs. Once the big victim is subdued by the con-
strictor's embrace or by a dose of poison, the snake must swallow
it whole, because no snake has cutting teeth suitable for slicing
the victim's body into bite-sized pieces.
Here is the nub of the problem: Snakes are long, narrow beasts
with heads of very small width compared to many lizards and most
frogs. Such a small, narrow head is a necessary component of the
snake's fundamental mode of movement, sliding through narrow
paths and down burrows. A giant tropical toad may have a mouth
nearly as wide as its body is long, and so it can gulp down prey
nearly as large as itself. But the poor puff adder, having success-
fully brought down a monkey offering enough meat to keep the
snake going for a month, now faces an item of food at least twice
the width of its own mouth. The solution to this gustatory di-
lemma has generated the most elegant cranial architecture in land
vertebrates.
70 | THE CONQUERING COLD-BLOODS: A CONUNDRUM
How to swallow something larger than your head—snake-style. A view
directly into the wide-open mouth of a boa constrictor. All the upper and
lower jaw bones are loosely connected by elastic ligaments, and each side of
the skull has not one but two rows of curved teeth.
A great snake in the act of swallowing something larger than
its head presents a marvel of reptilian engineering. The snake ma-
nipulates its prey's body with its mouth, until it faces the prey's
Robert T Bakker Page 7
