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| Unknown Facts About a Well-Known
Bird |
August 10th, 2003.
By Professor Fabio Cupul
Permanent Member of the Mexican Association for
the Dissemination of Science and Technology. |
 Who
among us hasn’t had some succulent chicken at
one time or another, Bar-B-Q’d, fried or in a
wonderfully rich broth, just to enjoy its appetizing
flavor? It is so common to watch how they are prepared
at every street corner, sold by weight in the supermarkets
or walking around in the back yards, patios and even
the streets of Vallarta.
Anyone of us can probably recognize
a chicken, a hen or a rooster just by seeing its image
in a photo or by hearing its characteristic “cock-a-doodle-doo”.
Nevertheless, although their presence in our lives is
so familiar, we probably know very little or nothing
about their natural history, a history as fascinating
and important as the reasons for which they became one
of man’s favorite species, along with dogs and
cats, to keep him company in his cultural development.
Hens and their male counterparts,
the roosters, belong to the galliformes order, a group
of birds of great economic importance as it includes
a great variety of species known as “poultry”:
turkeys, quail, pheasants and partridges. They all share
the characteristics of being robust, with strong feet
to run along the ground, nails that are especially adapted
to scratch around in search of food, and able to fly
in short, straight bursts alternating between gliding
and quick wing flaps.
 Galliformes
feed on grain, seeds, roots and tender sprouts which
they grind and reduce to a pulp using a muscle structure
called the gizzard. The gizzard’s muscular action
replaces the grinding function of teeth that are absent
in this group of animals. Moreover, in grinding their
food, they use little stones and sand that they swallow
specifically for such purpose, thus their constant eagerness
to scratch around on the ground.
Beaks are short and curved at the
point, while the upper mandible is longer and wider
than the lower one. Roosters differ from hens by the
greater development of their facial structures that
form the enormous “combs” and chins, or
by the presence of spurs on their feet and a showy plumage.
The roosters’ red comb and chin play an important
role in the courtship rituals as their brilliance is
a reflection of their genetic and physical health, attributes
that any good mother hen would like to leave to her
descendants.
When it comes to their habits, poultry
animals are strictly daytime creatures, gregarious and
polygamous. Cocks of the best fighting races are notorious
for their aggressiveness and courage when facing their
rivals. The species’ high rate of reproduction
is an important characteristic considering that we appreciate
both its eggs and its meat as food. Unless they are
taught differently, females lay their eggs on the ground,
or among the weeds or high grasses. Every once in a
while, domestic chickens start to brood, i.e.: they
stop laying eggs and show a strong tendency to sit on
their nests in order to incubate their eggs. The incubation
period lasts about three weeks. The chicks are precocious:
when they break out of their egg shells, they are not
naked. They are covered with down feathers and they
can begin running right away. Although they are able
to feed themselves, the newborn chicks can survive for
nearly a week without eating thanks to the egg yolk
they carry within their abdomens.
 Although
chickens are common throughout the world, it is known
that they come from the wild chicken called “bankiva”
(Gallus gallus) that originated in the woods of Southeast
Asia, from India to Bali in the southeast and to northern
Vietnam on the northeast. The appearance of the “bankiva”
varies very little from that of today’s domestic
chickens. Its descendents are without question the most
useful of all poultry, because of the high energy level
of their meat and their eggs. In addition, they are
used as fighting animals because of their combative
territorial spirit, or as decorative elements due to
their beautiful plumage.
There are approximately 175 varieties
of chickens, classified according to the geographical
areas where they were grown and developed, thus the
Asian, American or Mediterranean varieties, among others.
Chickens are relatively small birds
in comparison with other domestic animals such as horses,
cows or pigs. That characteristic, in addition to their
versatility in adapting to nearly any type of climate
and atmosphere, surely helped to attract ancient man’s
attention to this animal. In Zoroastrianism, religion
founded by Zarathustra in ancient Persia (today’s
Iran) around 630 B.C., the rooster is a being from which
we should learn four things: to fight, to get up early,
to eat with the family (as we always see them feeding
in the company of their chicks and other relatives),
and to protect one’s spouse when she is faced
with any kind of predicament.
Considering that the hen lays eggs,
some cultures linked its image with the concept of fertility.
Also, this concept is probably what caused it to be
used traditionally as a sacrificial animal in an infinite
number of pagan religious rituals. Furthermore, it is
believed that if the hen lays an even number of eggs,
misfortune will follow. On the other hand, because the
rooster crows at sunrise, it has always been symbolic
of the sun, ever since ancient times.
The domestication of chickens occurred
in ancient China around 1,400 B.C. However it is believed
that they originated in Burma (today’s Myanmar)
and adjacent lands approximately 3,300 years ago. Others
claim that the total domestication of this fowl occurred
around 2,000 B.C. This process of artificial selection
on the part of man has given rise to around 200 known
varieties of chickens nowadays.
Chickens have a relatively short
lifespan. Some may live as long as 10 or 15 years, but
that is the exception, not the rule. In the enterprises
dedicated to commercial egg production, chickens are
only valuable for the first 18 months of their lives
because their efficiency in laying eggs diminishes with
time. Once they reach that age, they are replaced by
new, younger birds. They need to be only six months
old to reach sexual maturity and begin producing eggs,
for a period lasting from 12 to 14 months.
Finally, despite the fact that chickens
have made our lives more bearable by adding their own
grain of sand to bring more variety and flavor to our
diet, many farms should provide them with a more dignified
lifestyle by feeding them better, giving them more comfortable
living quarters and work schedules that are slightly
less arduous …because, although they are created
to satisfy our demands, any breath of life should be
respected simply for sharing this planet with us.
Vallarta’s Nature Field Guide -
File 2: The Tarantula
 In
1994, the discovery of a new endemic species (one that
lives in one particular place and no other) of tarantula
was revealed on the Pacific coast of Mexico: Brachypelma
klaasi. Its distribution is restricted to the states
of Nayarit, Jalisco and Colima. Generally, it is either
brown or black in color and it can live in holes dug
in the ground just as well as in cavities in the rocks,
or high up in the trees. It only ventures out to hunt
for insects (many of which are a plague for agriculture)
or to look for a partner (males look for females with
the purpose of mating). Females may live as long as
30 years while males only reach around 10. Like many
of its relatives, they are in danger of disappearing
because of the loss of their habitat and their illegal
trade as pets.
Over millions of years, tarantulas
have developed a biological weapon to acquire their
food: poison (venom). They use it when they hunt, to
subdue and immobilize crickets, beetles, flies, cockroaches,
small lizards and snakes, injecting the victim by means
of a pair of hollow teeth. The venom possesses enzymes
that allow the spider to digest the food partially,
converting it into a sort of liquid that it will suck
until nothing but the inert shell of the poor prey remains.
The poison takes about five minutes to kill a cricket
and although a tarantula bite may be painful to humans,
no death has ever been attributed to it.
Professor Cupul is a Permanent
Member of SOMEDICYT, the prestigious Mexican Society
for the Dissemination of Science and Techniques
cupul@pvmirror.com Archives
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