Chameleons are a group of over one hundred
lizard species living in Madagascar, Africa,
Asia, and Europe. They are famous for the ability
to change color, first noted in the third century
b.c.e. by Aristotle. In most cases, chameleons are
brown, green, or yellow. Their skins can change to
almost any combination of those colors, as well as
to pinks, reds, blues, and purples.
Chameleon species are mostly arboreal. They
inhabit southern Spain, Crete, the Saudi Arabian
peninsula, Sri Lanka, India, Madagascar, Pakistan,
and most of Africa. North American colorchanging
lizards, particularly anoles, arewrongly
called chameleons.
Physical Characteristics of Chameleons
Chameleon maximum body lengths range from
one inch to three feet, depending on species. Like
other reptiles, chameleons are cold-blooded, with
body temperatures the same as those of their surroundings.
A chameleon body is flat from side to
side; it both looks smashed out of shape and has
dorsal and ventral crests, which provides camouflage
by making it resemble a leaf.
Chameleon eyes, placed on the sides of their
heads, can rotate in a full circle, and rove separately
or together. This is thought to be partly because
chameleons have short necks that do not
turn. It is useful for carnivorous chameleons seeking
food (insects, spiders, scorpions, and mammals)
and not wishing to be eaten themselves.
Using independent eye motion, they may seek to
eat an insect seen out of the left eye and use the
right eye to check for predators that might eat
them.
Arboreal chameleons have feet that grasp
branches like hands. This is because their feet are
zygodactyl, with toes of each foot facing in opposite
directions, and can wrap around twigs and
branches. This helps them to navigate safely in
trees. For the optimum arboreal equilibrium, chameleons
have prehensile tails to grip branches.
The tails curl into snail-like spirals when not
needed. Ground-dwelling chameleons lack the
prehensile tails and zygodactyly.
Some chameleons have on their heads horns
which, spearlike, stick out from spaces between
upper lips and eyes. They are used in mating and
protecting territory. The heads of most chameleons
are flat on top and wide on each side, making
it seem that they are wearing helmets. Chameleons
move slowly and carefully on tree branches.
However, their rapidly moving, body-length
tongues quickly shoot out of the mouth to catch
prey on sticky, mucus-rich ends, and bring it back
before escape is possible.
Chameleon color changes are due
to skin chromatophorea, which hold
pigments and pigment-making components.
To change color, chameleons
send hormone signals through the
blood, changing the identities and
thus the colors of chromatophore
pigments. Chameleon color changes
indicate fear, changes in light intensity
and body temperature or
other environmental changes, and
attempts to blend into surroundings
and to attract or deter potential
mates.
Life Cycle of Chameleons
Most chameleons are arboreal. Exceptions
include pygmy (stumptailed)
chameleons, which are small,
ground-living, and lack prehensile
tails. Male chameleons are territorial.
In many cases, male invaders of
a territory are fought actively and
the battle ends in the death of one
male. In some cases, the combat is
ritual, though the male who is faced
down leaves.
Males and females are solitary,
coming together only to mate. Most
color changes indicate breeding intentions,
pregnancy, or, on the part
of females, disinterest. Regardless
of species, chameleons mate year
round. Females can lay fertilized
eggs several years after mating because
they store sperm and can delay
their fertilization.
Females lay batches of ten to sixty eggs, in
some cases in burrows, in others in trees. In
vivaparous species, the young, developed from
eggs carried by mothers, are expelled onto tree
branches. After laying eggs or depositing their
young, females have no further contact with offspring.
Young chameleons break out of their eggs via
egg teeth, designed for this purpose. The egg
teeth later fall out, as they have no other use.
Chameleons live for five to ten years, if they reach
old age.
Three Representative Chameleon Species
Common chameleons (Chamaeleo chameleon chameleon)
inhabit southern Spain, northern Africa,
and the Mediterranean coast of the Middle East.
Arboreal, they grow to ten-inch body lengths,
with ten-inch tails and ten-inch tongues. They eat
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only insects, and mate in late summer. Females
lay batches of twenty to thirty eggs.
Flap-necked chameleons (Chamaeleo dilepts
dilepts) are named for skin folds near their necks
and ears. They are arboreal and inhabit South Africa.
They eat insects, spiders, and scorpions, and
grow up to about fourteen inches long. These chameleons
change color extensively, starting from a
mix of brown and yellow.
Panther chameleons (Chamaeleo pardalis) of
Madagascar are arboreal, grow to twelve inches
long, and eat insects. They are aggressive and territorial,
named for their ferocity, and fighting between
males is to the death. Females lay thirty to
fifty eggs.
Chameleons are not harmful to humans. They
are actually ecologically beneficial, eating many
insect pests. Chameleons are also thought desirable
pets by many people. However, they are difficult
to maintain in captivity.
Classification:
Kingdom: Animalia
Subkingdom: Bilateria
Phylum: Chordata
Subphylum: Vertebrata
Class: Reptilia
Subclass: Archosauria
Order: Squamata
Suborder: Sauria (lizards)
Family: Chamaeleontidae (chameleons)
Genera: Chamaleo (twenty-four species), Brookesia
(four subgenera, eight species)
Geographical location: Madagascar, Africa,
Asia, and Europe
Habitat: Land-dwellers; mostly arboreal, though
some live on the ground
Gestational period: Females lay ten to sixty fertilized
eggs, which hatch on their own
Life span: Five to ten years
Special anatomy: Eyes that rotate 360 degrees,
zygodactyl feet, prehensile tails, spearlike
horns for mating and combat, long sticky
tongues
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