Special Sub-Topic: Those Howling Monkeys
|Where in the world do these noisy monkeys live?|
South and Central America. They choose to live in the rain forests in tall trees where they are known to walk (yes walk) from tree to tree without coming to the ground. They are the largest of the New World monkeys.
|What makes their sound so loud?|
special vocal sacs or chambers. Before writing this quiz, I listened to their sounds, and truly it does sound like "barking,"or "whooping." Someone has rather disparagingly noted that a female's vocalization sometimes sounds like a "pig's grunt." [This "someone" was William Henry Hudson in the novel "Green Mansions."]
In their large throats, they have unique hollow, egg-shaped chambers which augment the sound. This is physiologically called an "enlarged hyoid bone."
They seem to call out the loudest either at dawn or late afternoon, and it is estimated that they can be heard for approximately three miles.
|What term best defines the howler monkey's primary form of locomotion?|
quadrupedal. The howler monkeys have what amounts to an additional limb in their incredibly strong prehensile tail, which may be as large as the monkey itself. Their movement is classified as quadrupedal.
Saltatory locomotion refers to leaping, hopping and jumping of certain insects. Plantigrade refers to the walking of mammals with feet on the ground.(humans, opossums and rabbits are some examples of plantigrade locomotion) Digitigrade locomotion refers to walking on the toes, such as cats, dogs and walking birds, among others.
Howler monkeys move very slowly, spending an inordinate amount of time on top of trees, munching away at and digesting leaves. Researchers estimate that they may spend as much as seventy-five percent of their time resting.
|To what predator are the young howler monkeys particularly subject?|
harpy eagle. The young howler monkeys often hang on to the stomachs of their mothers for the first months of their lives. The harpy eagle is known to have a seven-foot wingspan, and they have also actively attempted to capture male howler monkeys. It is the largest and strongest raptor in the Americas. The female can weigh between fourteen to twenty pounds.
|What is true of both the male and female howler monkey's vision?|
trichromatic color vision. Having trichromatic vision enables many Old World monkeys, apes and humans to perceive three colors and thus to discriminate finely among greens, blues and
In contrast, the howler monkey is unlike many of the other New World monkeys in being trichromatic. In contrast, the owl monkeys, being monochromatic, recognize black, white and some grays.
See Jacobs, G. H.; Neitz, M., Deegan, J. F., & Neitz, J. (1996). "Trichromatic colour vision in New World monkeys". 'Nature' 382 (382): 156-158.
|These monkeys have very unique noses. Their noses do not open like humans do. In contrast, how do they open?|
platyrrhine. Platyrrhine means that the nose has a wide septum and that the nostrils open to the sides. Catarrhine noses have a small septum and the nostrils open down wards. The structures of their noses are used to distinguish them from Old World monkeys. The New World monkeys of which howler monkeys are a part are scientifically named Platyrrhini or "flat nosed," which points to their signature "flatter" noses and nostrils facing to the side, compared to the Old World monkeys' far narrower noses.
|What best describes the diet of these unusual primates?|
folivore. A folivore is an herbivore that eats leaves. Other mammals that are folivores are okapis, sloths, possums, koalas and some types of monkeys. Interestingly, folivores have slower than normal metabolism and very long digestive tracts. The koala is probably the most famous folivore.
|Why do biologists believe these male monkeys howl so at dawn and late afternoons?|
mark out turf. Most believe the howling is primarily a way of establishing turf, to communicate and make their whereabouts known. There is some very interesting research on the howling of female howler monkeys. It appears females howl too, and that they may howl to provoke competition among the males.
|What color is the female black howler monkey? |
blond. The male howler monkey is black, while the female is blond. Sexual dimorphism is the name for this difference in form between members of different sexes in the same species. One instance of sexual dimorphism occurs in lions: males have a mane and females do not.
|Of course, you need to know what a group of howler monkeys is called. What is the collective name?|
troop. These "troops" usually consist of fewer than twenty members. There will be active struggles by males for positions of dominance in the troop. It seems that these struggles are mainly verbal. However, when a male wins, he will often commit an act of violence and mate then with as many females as he can so that his position of dominance will last.
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