Dwarf Antelopes
Dwarf Antelopes
Habitat
Characteristics
Parenting
Resources
These small antelopes belong to the subfamily Neotraginae of the ruminant family Bovidae. A total of 13 species are classified together in the subfamily Neotraginae, including the dik-diks, grysboks, steen-bok, and other dwarf antelopes. Dwarf antelopes range from extremely small (3.3-4.4 lb or 1.5-2 kg) hare-sized royal antelope (Neotragus pygmaeus ) and dik-diks (Madoqua spp.) to the medium-sized oribi (Ourebia ourebi ) and beira (Dorcatragus megalotis weighing from 30-50 lb (10-25 kg). Dwarf antelopes engage in territorial scent marking and possess highly developed scent glands. They are browsers, consuming a diet of young green leaves, fruit, and buds. Dwarf antelopes are also usually not dependent upon regular supplies of drinking water for their survival.
The food of the herbivorous dwarf antelope is digested by means of the four-chambered ruminant stomach. Dwarf antelopes browse or graze, consuming vegetation that is nutritionally rich. They lightly chew their food as they tear leaves from branches. After the food is swallowed, it enters the rumen of the stomach. Digestion is then aided by the process of bacteria breaking down nutrients. The food pulp is then regurgitated and chewed as cud to further break down the food before being swallowed and digested more completely.
Dwarf antelopes are found in various terrains throughout the sub-Saharan regions of Africa. The klipspringer (Oreotragus oreotragus ) is found in rocky areas in eastern and southern Africa. Four species of dik-diks are found in dry bush country in the Horn of Africa, that is, Somalia and Ethiopia, as is the beira. Oribis are found in the savanna country, from West to East Africa and in parts of southern Africa.
Steenbok (Raphicerus campestris ) inhabit bushy plains or lightly wooded areas in southern Africa, while the two species of grysbok (R. melanotis and R. sharpei ) are found in stony, hilly areas and scrubby flat country in east-central Africa and the extreme south of the continent. The royal antelope is found in dense forests in West Africa, and Bates’ pygmy antelope (Neotragus batesi ) is found in the forests of the Zaire. Sunis (N. moschatus ) live in forests along the southeastern edge of Africa.
The horns of dwarf antelopes are short, straight spikes found only in the males, although klipspringer females sometimes have horns. Colorations are usually pale, varying from yellow to gray or brown with a white rump patch, while the steenbok is brick-colored. All dwarf antelopes have well-developed scent glands, particularly preorbital glands which can be easily seen on most species as dark slits beneath the eyes. Dwarf antelopes generally have narrow muzzles, prominent ears, and their nostrils are either hairy or bare.
Dwarf antelopes are territorial and many are in lifetime monogamous relationships. They tend to be solitary even though a mated pair shares the same territory. Territories can range in size from several hundred square feet to tens of acres depending upon the nature of the territory and the density of the group’s population. Some monogamous pairs may have a second female, usually a female offspring that has not left the parental territory. Some dwarf antelope males may have two or more females within a small territory.
Scenting behavior among dwarf antelopes maintains the mating bond and protects the territory from
KEY TERMS
Monogamy— Mating relationship where a male and female tend to become permanently paired.
Preorbital scent glands— Glands located below the eyes that are used to mark territory.
Scent-mark— To spread urine, feces, or special fluid from a body gland along a trail to let competitive animals know that the territory is taken.
intruders. Males mark their territory with the scent glands found under their eyes (preorbital glands), and on their hooves (pedal glands). They can mark both the ground of their territory, as well as branches and bushes. Additionally, males will scent their mates, which strengthens the ties between them. Ceremonial behavior in dunging is also seen. A pair will follow one another and deposit urine and feces on the same pile.
Males can be aggressive in defending their territories. They have been known to use their sharp horns to wound intruders. Usually, however, male rivals for females will more often only display aggressive behavior to one another before one retreats. The display of aggressive behavior can include pawing the ground, horning, alarm calls, chasing, and pretending to attack.
Dwarf antelope females give birth to one offspring at a time, coinciding with seasonal rains. The gestation period is around six months, depending on the species. Infants hide in the grass for several weeks and the mother returns to feed them twice a day. As the fawn grows, it begins to follow the mother. Young females mature by the age of 6-10 months, while males reach maturity around 14 months. Somewhere between 9-15 months, young dwarf antelopes leave the territory to establish themselves on their own.
In klipspringer families, the pair are found close together, on the average 12-45 ft (4-15 m) apart, and the male assumes the role of lookout while the female cares for the offspring. The male may even become involved with feeding the young klipspringer.
See also Antelopes and gazelles.
BOOKS
Estes, Richard D. Behavior Guide to African Mammals. Berkeley: University of California, 1991.
Haltenorth, T., and H. Diller. A Field Guide to the Mammals of Africa. London: Collins, 1992.
Nowak, Ronald M. Walker’s Mammals of the World. 6th ed. Baltimore: The Johns Hopkins University Press, 1999.
Vita Richman
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Parathyroid gland involvement by papillary carcinoma of the thyroid gland
Magazine article from: Archives of Pathology & Laboratory Medicine; 12/1/2002; ; 700+ words
; ...measured the size of the parathyroid gland on glass slides and...numbers of examined parathyroid glands histologically...primary tumor into the parathyroid gland as an expansive growth...cancer nests and the glands (pattern B, Figure...
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Multiple ectopic parathyroid glands
Magazine article from: The American Surgeon; 11/1/2000; ; 700+ words
; ...The left superior parathyroid gland was readily identified...pole of the thyroid gland at the level of the...cartilage. No other parathyroid glands were identified in...sheath. Both inferior glands were then located in...revealed the left inferior parathyroid gland ...
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The carcinoma of parathyroid gland
Magazine article from: Indian Journal of Cancer; 4/1/2004; ; 700+ words
; ...functioning carcinoma of the parathyroid gland in 1933.[2] The incidence...within an adenoma / hyperplasic parathyroid gland or in association with celiac...findings is unclear.[1],[6] Parathyroid carcinoma has been reported...
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Double Adenoma of the Parathyroid Gland.
Magazine article from: Archives of Pathology & Laboratory Medicine; 2/1/2001; ; 700+ words
; ...there will be 1 enlarged parathyroid gland, and the other parathyroid glands will appear grossly normal...excision of 1 abnormal parathyroid gland is associated with a lack...several or all of the glands are abnormal, since the...
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Localization of parathyroid glands using technetium-99m-tetrofosmin imaging
Magazine article from: The Journal of Nuclear Medicine; 5/1/1997; ; 700+ words
; ...determination of intact parathyroid hormone (PTH). The...hyperparathyroidism are parathyroid adenoma or chief cell...localizing the involved gland(s). While this...patients with ectopic glands or glands located within the thyroid gland, where localization...localization of the ...
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The parathyroid glands, primary and secondary hyperparathroidism and assays for parathyroid hormone.(Clinical report)
Magazine article from: Journal of Continuing Education Topics & Issues; 8/1/2007; ; 700+ words
; ...Background The four parathyroid glands are bean-sized...near the thyroid gland. These glands synthesize parathyroid hormone (PTH or...when a parathyroid gland becomes overactive...forms on one of the parathyroid glands causing it to grow...
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Parathyroid glands regulate blood calcium levels.(Life - Health)
Newspaper article from: Albany Times Union (Albany, NY); 5/24/2005; 700+ words
; ...your thyroid gland. Behind the thyroid gland and stuck to its backside are four parathyroid glands - small glands that regulate the blood...level lies between 9.0 and 10.5. Parathyroid gland hormone coaxes calcium out of bone and...
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Surgeon-Performed Ultrasound Improves Localization of Abnormal Parathyroid Glands/DISCUSSION
Magazine article from: The American Surgeon; 7/1/2005; ; 700+ words
; ...localization of abnormal glands is the initial step toward...parathyroid, distinguish parathyroid from thyroid tissue, and...differential elevation of parathyroid hormone (PTH). Operative...patients: 1) showed no parathyroid gland in 22 patients, 2) suggested...
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Parathyroid gland tumor raises blood calcium
Newspaper article from: Sun-Journal Lewiston, Me.; 1/8/2007; 700+ words
; ...mentioned that the parathyroid was the cause of this...neighbor of." The four parathyroid glands, about the size of...back of the thyroid gland in the lower neck. The hormone these glands make - parathyroid hormone - regulates...
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Parathyroid glands regulate blood calcium
Newspaper article from: Sun-Journal Lewiston, Me.; 6/11/2008; 700+ words
; ...size parathyroid glands are stuck to the back of the thyroid gland in the neck. Their proximity to the thyroid gland gave them the name parathyroid. These glands regulate the blood...the glands secrete parathyroid hormone, which tells...
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parathyroid glands
Book article from: The Columbia Encyclopedia, Sixth Edition
parathyroid glands , four small endocrine...located behind the thyroid gland, that govern calcium...in parathormone, the parathyroid hormone. Parathormone...caused by tumor of the parathyroid glands, is a serious disorder...
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Parathyroid Hormone Test
Encyclopedia entry from: Gale Encyclopedia of Medicine, 3rd ed.
...hormone secreted by the parathyroid gland in response to low...healthy bones. The parathyroid glands are small paired...of the parathyroid glands. It is rarely caused...phosphate, and the parathyroid gland secretes PTH in an...
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parathyroid hormone
Book article from: A Dictionary of Food and Nutrition
parathyroid hormone The hormone secreted by the parathyroid glands; four glands situated in the neck near to the thyroid gland but not connected with its function. The hormone is secreted in response to a fall in plasma calcium, and acts on the...
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parathyroid
Book article from: The Oxford Pocket Dictionary of Current English
par·a·thy·roid / ˌparəˈ[unvoicedth]īˌroid / • n. Anat. a gland next to the thyroid that secretes a hormone ( parathyroid hormone ) that regulates calcium levels in a person's body.
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Parathyroid Cancer
Encyclopedia entry from: Gale Encyclopedia of Cancer
Parathyroid cancer Definition Parathyroid cancer is a rare, slow-growing tumor of a parathyroid gland in the neck. Description The four parathyroid glands in the human body are designated as the right superior...
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