The suborder Sauria contains the lizards, and not the crocodilians or the
dinosaurs as suggested by our friend Webster 1913, below. Within this suborder
are five infraorders, containing 19 families, which are at times further divided
There are 4636 lizard species currently extant
worldwide, in addition to those
that may be discovered at some later date. They are found on six of the seven
s (the exception being Antarctica
, for obvious
). They are generally small, cold-blooded, have scale
s covering their
entire body and have two pairs of limbs. They may be nocturnal
, and must rely on their environment to heat their bodies. They have
s, unlike snakes
, and always have small openings posterior
the eyes which lead to the auditory anatomy
. All lizards produce young through
, and the normal reproductive strategy involves laying from two to dozens of
eggs in a well-hidden burrow or mound. Some, on the other hand are ovoviviparous
meaning that while the embryo
s do develop in eggs, the eggs are retained inside
the body of the female until such time as they hatch. These species give birth to
live young, in a manner superficially similar to mammal
s. Most lizards are
insectivorious, but there are top predators and herbivore
s in the suborder.
Many lizards are drab
in their colouration, and are generally pretty unremarkable
in appearance and behaviour (except, of course, to herpetologists
). There are, however, some exceptional and
fascinating members of this family which deserve special mention. Instead of trying
to list them all here, I've chosen instead to mention a specific individual for
each interesting behaviour
Many lizards are capable of dropping their tail when threatened by a predator
which is a particularly good anti-predator defense. The five-lined skink
), found across North America
, is a perfect example of
such a species. It is a small, insectivorious species which, when threatened by a
predator such as a bird, cat or dog, will drop its tail and scamper off to safety.
The other common anti-predator defense used by lizards is crypsis, which is the
tactic of remaining hidden or camouflaged so that the predator cannot see the prey.
Almost all lizards are coloured and patterned in such a way as to blend in with
their surroundings, but the chameleon
s take this strategy several steps further.
They are capable of changing their colour and pattern using the chromatophore
. They also move along branches of trees by rocking back and
forth, making them appear remarkably similar to a leaf moving in the wind. These
two adapatations make them able predators and particularly difficult prey.
Other antipredator defenses
Some other lizards have adopted different antipredator defenses. Notable amongst
these are the behaviours of the horned toad
and some young skinks and monitors.
The horned toad, when threatened, dramatically increases the pressure
surrounding their eyes, causing them to burst and shoot
streams of blood
considerable distances. Young monitors, on the other hand, have
a habit of defecating
threatened, and given their carnivorous and scavenging diet, this is not a pleasant
experience for any
animal in the immediate vicinity
stench similar to a skunk
s, but with a liquid which burns and sticks
and you've got their anti-predator defense figured out).
While the subfamily serpentes has large numbers of venomous species (cobra
, death adder
, etc.), there are two lizard species which are venomous: the
and the Mexican beaded lizard
. These two species, rather than
having fangs, produce their venom in their saliva gland
s and inject it into their
prey as they chew. The venom is not particularly powerful, and not considered life
threatening to humans, but is an evolutionary wonder.
While not venomous, per se
, the komodo dragon
also has the ability to
prey using its saliva. The komodo has a large and diverse bacterial
living in its mouth, and these bacteria cause all mammals to fall very ill,
often fatally. They use the bacteria to incapacitate larger prey such as deer and
small humans. The komodo will attack their prey, and if they can't kill it
immediately, will innoculate the mammal
bacteria. Days later, the prey will succumb to the sickness and die, and the komodo
will then consume the carcass
(yes, they will follow the animal for days
waiting for them to collapse).
While many lizards are terrestrial
or even subterranean
, many make their living
up in the forest canopy. The chameleon, already mentioned, has evolved feet which
help it grip the branches of trees in a very controlled manner. The toes have fused
together in both the fore- and hind-feet, giving the animal two pads instead of
five toes. These pads grip branches strongly, giving the chameleon a very good
ability to remain aloft even under high winds.
Another species, the monkey-tailed skink, has evolved a powerful,
prehensile tail which is used to grip the branches and trunks of trees. These
herbivorous lizards are quite large, and so use this tail to remain anchored to the
tree while they extend their bodies in order to reach the leaves which they
And the cult was born ...
Finally, the basilisk
s have one of the most amazing abilities in the entire
subfamily. These Amazonian
lizards have very long toes on their back feet,
which are principally used to help the animal climb but also allow them to
literally run across the surface of the water. By ]rearing up] on their hind legs
and moving them like a windmill
, basilisks can run considerable distances over
the surface of a pond when fleeing from a predator. They use the large surface area
of their hind feet and the surface tension
of the water to accomplish this wonderous feat
, earning them the common name
What follows is a list of the families and subfamilies within the suborder Sauria.
Next to each scientific name is the common name of the group and an estimate of the
number of species.
With most things taxonomic, this classification is not unanimously supported
in the academic community
. Some classifications place both the bird
s and some dinosaur
s within the Sauria. (Thanks go to Gorgonzola
for pointing this out).
Note that recent research suggests that chameleons change their
colouration most often to communicate with other members of the species, rather
than as camouflage.
Constructed, in part, with help from the Reptile Database,