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The largest snakes in the world are members of
the family Boidae, which includes the boa and the
python. Some members of this family never attain
a length of more than 0.6 m (2 ft), but the
largest may grow to more than 9 m (30 ft). |
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Sea snakes have no gills and
must rise to the surface for air, but they can
remain underwater for several hours, obtaining
dissolved oxygen from water that they swallow and
eject. |
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Approximately 2500 different species of snakes
are known. Approximately 20 % of the total number of the snake
species are poisonous.
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The skin and outer covering of the horny scales
are shed periodically and usually in one piece,
including the hard, transparent covering of the
eye known as the spectacle (snakes lack movable
eyelids, and the spectacle protects the
constantly open eyes). The frequency of shedding
varies with different species , according to the
size and age of the individual. Young, rapidly
growing snakes shed their skins more frequently
than the slow-growing adults. In some species the
skin is shed about every 20 days; in others, only
once a year. |
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The big pythons can eat animals that weigh up to
about 68 kg (150 lb), but swallowing such a meal
is a difficult process. |
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The snake must bite
to inject its venom; no snake
has a stinger in its tail. |
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Three species of
snake
can spit or eject the venom in a fine spray,
which is aimed at the eyes of an enemy and
projected for distances up to 2.4 m (8 ft). If
the venom gets into the eyes, it may cause
blindness. The spitting is used only in defense
and never to obtain food. |
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Vision is well developed in most snakes, but many
burrowing snakes are virtually blind. |
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Snakes have a strong sense of smell, which is
relied on to a large extent in hunting food. Snakes find their
prey by sight and scent, and sometimes temperature. Except for
burrowing species, snakes have excellent short-range vision. Their
sense of smell is extraordinary, thanks to a harmless, constantly
flicking forked tongue that carries scent particles to a
specialized sensory organ ('Jacobson's organ') on the roof of the
mouth. |
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Snakes are deaf to airborne sounds. The Cobra
does not hear, as it is believed, the snake-charmer’s
flute. They can, however, feel vibrations through
the ground or whatever they are resting on. |
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Snakes move slower than an adult human can run;
the fastest recorded speed achieved by any snake is about 13 km/hr (8
mph), but few can go that fast. |
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Depending on the species, snakes may be
egg-layers or give birth to live young. They generally mate in the
spring, shortly after leaving whatever hollow, burrow or rock
crevice has sheltered them through winter hibernation. Egg-layers
usually deposit groups of eggs in dirt, beneath stones or logs, or
in piles of decaying wood or vegetation during late spring or
early summer. Most snakes hatch or are born in late summer.
Whether deposited as eggs or dropped as fully formed miniature
adults, snakes are on their own from the start. Snakes do not take
any responsibility for the care and protection of their young.
Most snakes mature at one or two years of age, and individuals may
live up to twenty years in the wild. |
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The greatest age known for any snake is just under 30
years, attained by both the anaconda and the
black-lipped cobra. |
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Effects of
the bites of Black and Green Mamba -
Black and green mambas both produce neurotoxins, which is
why they kill so fast. Black mamba is more venomous. Neurotoxin inhibitors and antivenin are
generally made from the venom of the same snake, but it is likely
that antivenin from one would be at least partially effective
against the other. Because these are two different snakes
their venom has to be different and thus the antivenin from one
may not act for the other.
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Snakes do not leap or jump into the
air. Instead, those that do strike out coil themselves enough to
get a push or strong outward movement designed to snatch prey or
inject venom. Most snakes can only strike about one half their
total body length. They do not actually leave the ground. They
are capable of striking upward or outward at approximate one
half length level.
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