FORESTS,
THE HABITAT OF MONKEYS
AS AN EAST
WIND blasts through a gap in the Cordillera de Tilaran, a rugged mountain
range that splits northern Costa Rica in half, a female mantled howler
monkey moves through the swaying trees of the forest canopy.
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A
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Ken Glander,
a primatologist from Duke L University, gazes into the canopy, tracking the
female’s movements. Holding a dart gun, he waits with infinite patience for
the right moment to shoot. With great care, Glander aims and fires. Hit in
the rump, the monkey wobbles. This howler belongs to a population that has
lived for decades at Hacienda La Pacifica, a working cattle ranch in
Guanacaste province. Other native primates — white-faced capuchin monkeys
and spider monkeys — once were common in this area, too, but vanished after
the Pan-American Highway was built nearby in the 1950s. Most of the
surrounding land was clear-cut for pasture.
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B
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Howlers
persist at La Pacifica, Glander explains, because they are leaf-eaters.
They eat fruit, when it’s available but, unlike capuchin and spider
monkeys, do not depend on large areas of fruiting trees. “Howlers can
survive anyplace you have half a dozen trees because their eating habits
are so flexible” he says. In forests, life is an arms race between trees
and the myriad creatures that feed on leaves. Plants have evolved a variety
of chemical defences, ranging from bad-tasting tannins, which bind with
plant-produced nutrients, rendering them indigestible, to deadly poisons,
such as alkaloids and cyanide.
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C
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All primates,
including humans, have some ability to handle plant toxins. “We can
detoxify a dangerous poison known as caffeine, which is deadly to a lot of
animals:’ Glander says. For leaf-eaters, long-term exposure to a specific
plant toxin can increase their ability to defuse the poison and absorb the
leaf nutrients. The leaves that grow in regenerating forests, like those at
La Pacifica, are actually more howler friendly than those produced by the
undisturbed, centuries-old trees that survive farther south, in the Amazon
Basin. In younger forests, trees put most of their limited energy into
growing wood, leaves and fruit, so they produce much lower levels of toxin
than do well- established, old-growth trees.
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D
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The value of
maturing forests to primates is a subject of study at Santa Rosa National
Park, about 35 miles northwest of Hacienda La Pacifica. The park hosts
populations not only of mantled howlers but also of white-faced capuchins
and spider monkeys. Yet the forests there are young, most of them less than
50 years old. Capuchins were the first to begin using the reborn forests
when the trees were as young as 14 years. Howlers, larger and heavier than
capuchins, need somewhat older trees, with limbs that can support their
greater body weight. A working ranch at Hacienda La Pacifica also explains
their population boom in Santa Rosa. “Howlers are more resilient than
capuchins and spider monkeys for several reasons, Fedigan explains. “They
can live within a small home range, as long as the trees have the right
food for them. Spider monkeys, on the other hand, occupy a huge home range,
so they can’t make it in fragmented habitat”
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E
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Howlers also
reproduce faster than do other monkey species in the area. Capuchins don’t
bear their first young until about 7 years old, and spider monkeys do so
even later, but howlers give birth for the first time at about 3.5 years of
age. Also, while a female spider monkey will have a baby about once every
four years, well-fed howlers can produce an infant every two years.
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F
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The leaves
howlers eat hold plenty of water, so the monkeys can survive away from open
streams and water holes. This ability gives them a real advantage over capuchin
and spider monkeys, which have suffered during the long, ongoing drought in
Guanacaste.
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G
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Growing human
population pressures in Central and South America have led to the persistent
destruction of forests. During the 1990s, about 1.1 million acres of
Central American forest were felled yearly. Alejandro Estrada, an ecologist
at Estacion de Biologia Los Tuxtlas in Veracruz, Mexico, has been exploring
how monkeys survive in a landscape increasingly shaped by humans. He and
his colleagues recently studied the ecology of a group of mantled howler
monkeys that thrive in a habitat completely altered by humans: a cacao
plantation in Tabasco, Mexico. Like many varieties of coffee, cacao plants
need shade to grow, so 40 years ago the landowners planted fig, monkey pod
and other tall trees to form a protective canopy over their crop. The
howlers moved in about 25 years ago after nearby forests were cut. This
strange habitat, a hodgepodge of cultivated native and exotic plants, seems
to support about as many monkeys as would a same-sized patch of wild
forest. The howlers eat the leaves and fruit of the shade trees, leaving
the valuable cacao pods alone, so the farmers tolerate them
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H
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Estrada
believes the monkeys bring underappreciated benefits to such farms,
dispersing the seeds of fig and other shade trees and fertilizing the soil
with feces. He points out that howler monkeys live in shade coffee and
cacao plantations in Nicaragua and Costa Rica as well as in Mexico. Spider
monkeys also forage in such plantations, though they need nearby areas of
forest to survive in the long term. He hopes that farmers will begin to see
the advantages of associating with wild monkeys, which includes potential
ecotourism projects.
“Conservation
is usually viewed as a conflict between agricultural practices and the need
to preserve nature,” Estrada says. “We’re moving away from that vision and
beginning to consider ways in which agricultural activities may become a
tool for the conservation of primates in human-modified landscapes.”
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Questions 27-32
The reading Passage 3 has seven
paragraphs A-H.
Which paragraph contains the following
information? Write the correct letter AA-H in boxes 27-32 on your answer
sheet.
27
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A reference of reduction in Forest inhabitant.
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28
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An area where only one species of monkey
survived while other two species have vanished.
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29
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A
reason for howler Monkey of choosing new leaves.
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30
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Mention to
Howler Monkey’s nutrient and eating habits.
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31
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A reference of asking farmers’
changing attitude toward wildlife.
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32
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The advantage
for Howler Monkey’s flexibility living in a segmented habitat.
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Questions 33-35
Look at the list of places and the following
descriptions below.
Match each description with the correct
place, A-E.
Write the correct letter, A-E, in boxes
33-35 on your answer sheet.
List of places
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A
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Hacienda La
Pacifica
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B
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Santa Rosa
National Park
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C
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a cacao
plantation in Tabasco, Mexico
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D
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Estacion de
Biologia Los Tuxtlas in Veracruz, Mexico
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E
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Amazon Basin
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33
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A place where Howler Monkey’s benefit to the local region’s
agriculture
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34
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A place where it is the original home for all three native monkeys
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35
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A place
where Capuchins monkey comes for a better habitat
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Questions 36-40
Complete the sentences below.
Choose NO MORE THAN TWO WORDS from the
passage for each answer.
The
reasons for Howlers monkey survive better in a focal region than other two
species:
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√
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Howlers in La
Pacifica since they can feed themselves with leaf when 36………………………is not
easily found.
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√
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Howlers have
better ability to alleviate the 37………………………. which old and young trees used
to protect themselves).
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√
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When compared
to that of spider monkeys and capuchin monkeys, the 38 …………….. the rate of
Howlers is relatively faster (round for just every 2 years).
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√
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The monkeys
can survive away from open streams and water holes as the leaves howlers
eat hold the high content of 39………………………………. which ensure them to
resist to continuous 40………………………………………. in Guanacaste.
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