WEB PAGE OF PADIYIL VINOD SIVADASAN

                                  
 

Giraffe        

(Giraffa camelopardalis)

Courtesy of Dr. G. A. Simon  

The Giraffe is the tallest living quadruped animal. It is a ruminat, common in east Africa. The various types (three main types: Rothschild’s - Reticulated - and the Masai Giraffe) are distinguished by the color and pattern of the patches. Horns are found on both sexes but are merely short projections of bone covered by skin and hair. Despite the fact that the Giraffe has such a huge neck, it still has only 7 vertebrae, the same as most mammals. The male can reach the height of over 6 m. (average 5.5 m) while the female is about 1 m. less. Following a gestation period of 12-13 months, a calf of up to 1.6 m high is born.  

 
Zebra

The zebra is the African version of the horse. Male wt 250 kg, ht 127-140 cm; female wt 220 kg, ht slightly shorter than male. There is no gender difference in their color; background white to buff color; striping varies geographically and individually. Juvenile coat is longer with brown stripes.

Habitat: From southeastern Sudan to South Africa and west to Angola, in Somali-Masai Arid Zone, Southern Savanna, and South West Arid Zone. The zebra is one of the most numerous and successful large herbivores, adapted to a broad range of grassland habitats. Zebras often intermingle with other animals, most commonly the wilderbeest but also with topi and hartebeest

.The zebra is active mostly in daylight, spending nights preferably on short  pasture relatively safe from ambush. Zebras graze individually an hour or so at a time at night but move about very little. Resting zebras often steep soundly, but at least one herd member remains standing and alert. Mass movements between pastures and sleeping grounds, and to water at midday, are also peaks of social activity.

Social system: Harem masters have exclusive mating rights with 2 to 6 mares. Harems are so stable that mares remain associated for life; their foals gain added protection from the family stallion's readiness to defend his wives and offspring against all threats to their survival and his reproductive success. Home ranges can be as small as 30 km square in the best habitat, to over 600 km square in migratory populations. Harem ownership is about as safe as territory ownership: respected as long as the family stallion is fit enough to assert his rights. Colts leave their families on their own initiative usually between 2 and 3 years to join a bachelor herd, there to remain until mature and ready to start a harem at 5 years. Bachelor herds include 2 to 15 males, are usually led by a young adult, and are quite stable, with a rank order based simply on age.

Reproduction: Foals born in most months but a definite annual birth/mating peak early in the rains (Dec.-Jan. in East Africa). Mares in good condition conceive during the following "foal heat"; others reproduce at 2-year intervals. First foals at 3 to 3.5 years. Gestation period is 11 to 13 months. A mare labors lying on her side, while the herd remains nearby and the stallion stands watch. Foals weigh approximately 31-33 kg, are able to stand within 15 minutes and suckle in an hour. The mother keeps all other zebras away for several days, but once the foal is imprinted on her, she allows other herd members to contact it; its sibling can establish close ties through mutual social grooming. However, the place closest to its mother is taken by the newborn

 
African elephant   [Loxodonta africana

COVER

Size: Body length: 6-7.5m, Tail length: 1-1.3m, Shoulder height: 3-3.4m, Weight: Male 6000kg, Female: 4000kg.

African elephants are the larger of the two species (African and Asian), making them the largest land animal in the world. They have larger ears and tusks than Asian elephants. Large tusks are present in both sexes but females have shorter tusks. The skin is gray, with a little covering of hair. The skin has folds and up to 2.5 cm thick in places. Ears are large and fan-like, they are also used to control body temperature; blood circulating through the large vessels in the ears is cooled by flapping. Elephants are digitigrades with pads of fibrous tissue to cushion toe bones.

Habitat: African elephants are found in a variety of habitats south of the Sahara. Elephants are highly adaptable and can survive in forest, bush, savanna or desert. Migratory patterns are taught from one generation to the next. Now they are mostly restricted to parks and preserves.

Diet: Elephants have an inefficient digestive system and digest only about 40 per cent of what they eat. They eat enormously. Estimates in the wild range from 45 to 450 kg of vegetation per day (a 16 hour period). Zoo elephants are estimated to eat approximately 25 kg of food per ton of elephant per day. Working elephants need 150 to 300 kg of food per day and have therefore limited working time. Elephants eat almost anything green, but green grass, shoots and buds of trees and shrubs are preferred. Average daily consumption of water for full-grown animals is between 100 and 200 liters. Elephants are the only animals in Africa that dig deep holes in search of water. The holes, excavated using the trunk, can be several feet deep and it's thought the locations are learned from social interactions.

Social structure: Elephants live in a complex matriarchal society normally composed of 8 to 15 related members and led by a dominant cow. Three or four generations of cows and calves spend their entire lives together with the exception of males, who leave the group at puberty. Groups of related families stay in fairly close range of each other and communicate often; these are called kin groups. In times of danger, kin groups will mass and form clans of 200 or more. A primary mating factor is musth, a periodic hormonal cycle seen in both species. Physical manifestations in males include heavy secretions from temporal glands, high blood testosterone levels, urine dribbling (marking) and aggression. Cows seem to prefer a musth bull, but can successfully breed whether the bull is in musth or not. The cow's estrus cycle is roughly a monthly one and lasts 2-6 days. Gestation is approximately 22 months. The birth is usually a single one. Birth weight is 80 to 110 kg. Mother is often assisted by another cow during birthing. The calf can stand shakily and nurse a few hours after birth. Mammary glands are located between the front legs. Calves will nurse well into their third year and are very dependent on their mothers for eight to ten years. Adolescence at 12 to 14 years of age. Most physical growth is reached at 20, but growth continues throughout life. Top mental ability is at age 30 to 45. Death comes at 65 to 70 years of age when the last set of teeth wear out.

Special adaptation: The majority of the skull is honeycombed with sinuses to minimize weight. Tusks are elongated second upper incisors and grow throughout the lifetime. They are used for food gathering and carrying, as well as weapons. Molars make up other dental equipment; six consecutive sets of two upper and two lower molars are produced throughout life. The trunk is an elongation of the nose and upper lip; in adults it contains 40,000 to 100,000 muscles. Literally the animal's lifeline, it is used for eating, drinking, dust and water bathing, as well as communication. The sense of smell is highly sophisticated; they are believed to locate underground water by smelling the earth above. Vision is poor. Long lashes and nictitating lids protect the eyes from dust. Hearing is acute. Recent studies establish the use of infrasound (tones lower than humans can hear) for long-range communication.

Brain: Elephants have the largest brain size versus body weight other than man. Most mammals, excluding primates, are born with a brain weight of 90% of adult weight. A human brain at birth is 26% of adult weight, and the elephant's is 35% of adult weight. These statistics are used to distinguish instinctive from learned behavior, and are examples of higher intelligence.

Status in the wild: Endangered because of loss of habitat and because of poaching for ivory.

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