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| African (Bush) Elephant - Loxodonta africana | |
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| Topic Started: Jan 7 2012, 04:12 PM (60 Views) | |
| Taipan | Jan 7 2012, 04:12 PM Post #1 |
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African (Bush) Elephant - Loxodonta Africana Geographic Range African elephants were historically found south of the Sahara Desert to the south tip of Africa, from the Atlantic (western) coast of Africa to the Indian Ocean in the east. Currently their population is limited to several national parks and game reserves in southern Africa due to poaching and habitat destruction. (Estes, 1999)  Habitat The habitats occupied by African elephants vary because they can survive long periods of time without water; they occupy deserts, forests, savannas, river valleys and marshes. Physical Description Birth Mass : 105000 g (average) (3696 oz) Adult Mass : 3600 to 6000 kg; avg. 4540 kg (7920 to 13200 lbs; avg. 9988 lbs) African elephants are the heaviest land animal, and the second tallest in the Animal Kingdom. They are a sexually dimorphic species; males appear larger than females. The height of a bull at his shoulder is about twelve feet (about 3.75 m), when the female’s height is nine feet (about 3 m). They have enormous ears, each measuring about four feet (120-125 cm) across. They have a unique nose that is simply a long, boneless trunk extending from the upper lip. The trunk usually measures about five feet long (about 150 cm) and weighs around 300 pounds (about 135 kg). The two finger-like projections on the tip are so dexterous they can pick a blade of grass. The trunk itself is so strong it is capable of lifting 600 pounds (250- 275 kg). Their incisor teeth develop into tusks about 8 feet long (245-250 cm) and can weigh about 130 pounds (60 kg) each. The only other teeth they have are four molars which are replaced three times throughout their lives after the previous set wears down. African elephants have dark gray skin which is scattered with black hairs that wear off through the years. As a result the adults are mostly hairless. Their skin is about 2 1/2 inches (2-4 cm) thick, but flies, mosquitoes and parasites still penetrate it. There are two currently recognized subspecies which differ in their geographic location, tusk length, and weight. Forest elephants, Loxodonta africana cyclotis, typically reside in rain forests. They have more slender tusks and are smaller in height and weight than savannah/desert elephants (Loxodonta africana africana) who usually are found in grasslands.  Reproduction Breeding interval : Females give birth every four to nine years. Breeding season : Births occur more frequently during rainy seasons, but may occur throughout the year. Number of offspring : 2 (high); avg. 1 Gestation period : 22 months (average) Time to weaning : 48-108 months (average) Time to independence : 48-108 minutes (average) Age at sexual or reproductive maturity (female) : 10-12 years (average) Age at sexual or reproductive maturity (male) : 10-12 years (average) A females' estrus period lasts for about forty-eight hours. A bull in musth, a heightened state of sexual aggression and activity, must determine if the cow is in estrus by smelling her genitals. He inhales with the end of his trunk rubbing her genitals, then exhales with the end of the trunk in his mouth. This sends chemicals to his Jacobson’s organ, located in the palate, to test her condition for mating. Larger males with the largest tusks are usually around fifty years old and do most of the breeding; leaving the younger bulls to roam until a mate is found. Males constantly search for mates and rarely stay for more than a few weeks with a female and her herd. Elephants do not have any specific mating season. During the rainy seasons the reproductive rate is higher while times of drought or crowded conditions result in a lower reproductive rate. After a 22-month gestation period, single elephant calves are born weighing about 265 pounds (120-130 kg), twins are rare. A short time after birth, they instinctively are able to follow their mothers. Females give birth every four to nine years. Older calves are weaned a few months before the next is born. Sexual maturity is reached between 10 and 12 years of age. African elephant live about 70 years, they continue to grow in height during their lives, reaching a maximum of 13 ft (4-4.5 m) for males, and 9 ft (approx. 2.5-3 m) for females. (Estes, 1999; Eltringam, 1992) The calf is born into a nurturing herd of related females and young males. After a gestation period of 20-22 months, they are precocial as they can see, smell, and walk a short time after birth. These well-developed calves are guarded and taken care of by their allomothers; young females who assist the calf’s mother. Elephant cows of the herd, which are typically related, frequently suckle each others' calves. Daughters remain in their natal herd for life, sons leave their natal herd once they reach sexual maturity. (Eltringam et al., 1992; Estes, 1999; Moss, 1988)  Lifespan/Longevity Average lifespan (wild) : 70 years Average lifespan (captivity) : 80 years Elephants have one of the longest lifespans of all mammals- about seventy years. Their age can be determined by height comparison to the matriarch, tusk length, or more complicated methods like measuring the weight of an eye lens from an elephant that recently died. Aging elephants faces appear sunken and their ears fold toward their body as they get older. They may also suffer from arthritis, tuberculosis or blood diseases like septicemea. Accidental death can occur if an elephant falls down a hill, or if it loses a fight with another elephant. Deaths from poaching still outnumber any natural or accidental occurrences of death in elephants. Behavior African elephants wander day or night in non-territorial herds that can reach 200 elephants, even one thousand during the rains. Their society is based on a social matriarchal community. The matriarch is the oldest female who leads a clan of 9 to 11 elephants. Only closely related females and their offspring are part of this herd because males wander alone once they reach maturity. The herd’s well being depends on the guidance of the matriarch. She determines when they eat, rest, bathe or drink. As the matriarch begins to be limited by advancing age, around 50-60 years old, the next oldest replaces her and she is either abandoned or leaves by herself. Females in the herd practice motherhood by being allomothers to the calves. While the adults are sleeping (standing or laying on their sides), these assistants must protect the babies and retrieve them if they stray too far. Males, however, leave the herd at maturity and wander alone or in bachelor herds. Around 25 years old, they begin to compete for mates. Elephants display dominance with a raised head, trunk, and ears. They also snap their ears, shake their heads, make trumpeting noises and rumbles. They display submission by leveling their ears, lowering their heads, rubbing their eyes and swaying. African elephants are typically active during the day but herds in areas with high levels of human activity often become primarily nocturnal.  Food Habits Elephants eat vegetation like leaves, roots, bark, grasses and fruit. Each day they can consume anywhere from 220 to 660 pounds (100 to 300 kg) of food, and drink up to 50 gallons (190 L) of water. During the rainy seasons elephants eat grass and herbs like papyrus (Cyperus papyrus) and cat tails (Typha augustifolia). During dry seasons in the savannah they eat leaves collected from thorny trees and bushes. Swamps are a last resort for food because swamp vegetation contains little nutrition. However, dying elephants are often found in these areas because this vegetation is softer and older elephants are often missing teeth. (Estes, 1999; Moss, 1988) Predation Known predators :
The size of adult elephants leaves them invulnerable to wild animals. Humans are the only predators to adult elephants but calves are susceptible to be snatched away by lions and hyenas. If they sense a predator nearby, the largest cows instinctively herd the calves into a bunch around the matriarch. Next, they form circles around the cluster which creates protective layers that are impossible for predators to penetrate. (Estes, 1999) Ecosystem Roles Very few species can alter its own environment like elephants do. They demolish bushes, pull up trees by their roots and pack down the soil which can lead to erosion. This destruction also turns wooded areas into grasslands that are needed by grazing animals. Elephants create water holes by digging in dry riverbeds. They coat themselves with mud from the waters edge to protect from the sun and parasites, which creates a larger water hole. They can make and enlarge caves by searching for salts to eat. These caves are used for shelter for many different species. When elephants walk they stir up insects for birds to eat and easily disperse seeds which pass through their system undigested. The African Eggplant (Solanum aethiopicum) only grows after it has been through their system and fertilized by the elephant dung. (Estes, 1999)  Economic Importance for Humans: Negative Elephant foraging and wandering sometimes result in crop damage and damage to villages. (Eltringam et al., 1992; Estes, 1999; Jackson, 1990) Ways that these animals might be a problem for humans: crop pest. Economic Importance for Humans: Positive Humans have previously profited from ivory as it was used for jewelry, sculptures, pianos, and tools. Their hides were sometimes used for clothes and blankets and the local people ate their meat. Ecotourism activities revolving around seeing African elephants in the wild now provide significant sources of revenue for some regional economies in Africa. Ways that people benefit from these animals: body parts are source of valuable material; ecotourism . Conservation Status IUCN Red List: Vulnerable. US Federal List: Threatened . CITES: Appendix I. The African Elephant Conservation Act of 1988 is in full effect today, which bans any trade in ivory. The species’ status on the CITES appendix has moved to #1, from a monitored amount of trade to none. Though some conservation programs offer rewards, people have made movements to conserve and live with the elephants without being repaid. Conservation facilities exist in Africa, and societies to fuel them exist worldwide in Cameroon, England, Germany, Kenya, Netherlands, Sri Lanka, South Africa, Zimbabwe, Sweden, Tanzania, Thailand and the United States. In central eastern Africa, a number of wildlife conservancies hope to give endangered species a large protected area to live in and reproduce. They hope to see more action taken on predators and stop the illegal trade in ivory. Some parks and other areas that are being populated more and more with humans must control the number of elephants by controlled killing, or culling.  Other Comments Recent convincing genetic evidence suggests that the two subspecies of African elephants, L. a. africana and L. a. cyclopis, deserve separate species status. Extensive genetic divergence in 4 nuclear genes, along with distinct morphological and behavioral differences, suggests that these two kinds of elephants have been evolving independently for an estimated 2.5 million years. These results have profound implications for African elephant conservation efforts. -There are many physical differences between Asian elephants, Elephus maximus, and African elephants, Loxodonta Africana. African elephants are larger, have darker skin, and bigger tusks in both sexes. Asian elephants rarely have tusks. Asian elephants have a round back and two mounds on their forehead, whereas the African elephant’s back curves downward and has a smooth forehead. -Some parks in Africa are beginning to research elephants using radio-tracking systems. In this way they can observe their location, migratory patterns, and reproduction rates. -The word jumbo derived from an English circus elephant named by his owner because of his size. Currently, the word is used as an adjective. -Elephants typically walk 3-5 miles per hour and can reach 25 miles per hour by lengthening and quickening their strides. (Gordon, 1999; CITES, 2001; Moss, 2001; Estes, 1999) http://animaldiversity.ummz.umich.edu/site/accounts/information/Loxodonta_africana.html |
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| Taipan | Jan 10 2012, 10:46 PM Post #2 |
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Elephants Know Good People from Bad By Charles Q. Choi, Special to LiveScience posted: 18 October 2007 12:06 pm ET Elephants can apparently smell and see which humans might be out to get them, research now suggests. As elephants roam Amboseli National Park in Kenya within sight of famed Mt. Kilimanjaro, they may run afoul of members of the Maasai or Kamba tribes. While the Kamba nowadays threaten only elephants that invade their farmland, Maasai warriors occasionally show off their virility by spearing elephants. Since elephants face different levels of peril from people depending on their tribe, scientists reasoned elephants might use their senses to distinguish who might be dangerous. For instance, the pachyderms might rely on their eyesight—Maasai traditionally wear red shawls. The scientists also deduced that elephants might employ their keen sense of smell to distinguish Maasai from Kamba. Their body odors likely differ because Maasai eat substantial amounts of milk and occasionally cattle blood and beef while the Kamba diet consists of vegetables and maize, along with some meat. Also, unlike the Kamba, the Maasai use ochre and sheep fat in body decorations. The researchers had heard of several instances of elephants reacting "to even faint signals of Maasai, with elephants running away from Maasai men that were several kilometers away," said cognitive psychologist Lucy Bates at the University of St. Andrews in Scotland. The pachyderms even stayed away from a vehicle "for several days after Maasai men had been carried in it." Cognitive psychologist Richard Byrne at the University of St. Andrews, along with Bates and colleagues, tried displaying clean, unworn red and white cloths on bushes in Amboseli. They found elephants behaved significantly more aggressively toward the red cloths. "We think that this is the first time that it has been experimentally shown that any animal can categorize a single species of potential predator into subclasses based on such subtle cues," Bates said. The researchers also presented elephants with red clothing that had been worn for five days by either a Maasai or a Kamba man. The pachyderms reacted with greater fear toward the Maasai-scented clothing—they moved faster away and farther away, fleeing toward tall grass for cover, and took significantly longer to relax after they stopped running. The differences the researchers saw between elephant responses to sights and smells might relate to the amount of risk the pachyderms sense. "With any scent present, fear and escape reactions seem to dominate anything else," Bates said. Future research can focus on "what cues in the garments the elephants are attending to—what specific smells signal Maasai and Kamba? What aspect of the red cloths do the elephants respond to—the brightness, the hue?" Bates said. Moreover, "we don't know how many ethnic groups the elephants can discriminate, or how elephants respond to females of these groups—both of which would be interesting questions to answer," she added. The scientists, collaborating with the Amboseli Elephant Research Project, detailed their findings online Oct. 18 in the journal Current Biology.  Elephants aim the trunks toward something they wish to investigate, apparently helping them smell better. http://www.livescience.com/animals/071018-elephants-friends.html size=4]Elephant Tusks[/size] Uses Both male and female African elephants grow tusks. They have a variety of uses. They may be used to dig holes, rip up vegetation, strip bark from trees and lever heavy objects. They are also used for self-defence, and in aggressive attacks. Some animals can sometimes be seen resting their trunks on their tusks. What are tusks? Elephant tusks are upper incisor teeth, which grow very long. They are similar to human teeth, consisting of a central core of pulp, covered in dentine and encased in bone-like cementum. The internal dentine, making up 95% of the tusk, is the substance commonly referred to as ‘ivory'. It is a combination of mineral-based connective tissue and collagen proteins, making it very strong. Young elephants also have a layer of enamel at the very tip of their tusks but this is soon worn off and not replaced. How do they grow? At birth a small milk tooth, known as a ‘tush', is already in place. The full tusk grows behind this 5cm long tooth, breaking through at around one year old. As the tusks grow longer, ivory is formed within the central pulp cavity in the root and laid down in layers. Over time these layers form concentric circles similar to growth rings in trees.  These concentric lines can be seen clearly in a cross-section of a tusk. In addition, elephant and mammoth dentine has a characteristic cross-hatching pattern (also known as Lines of Schreger or engine-turnings) which can be used to identify ivory. This is not present in the tusks of other animals.  Tusks grow throughout an elephant's life although they may wear down or even break due to extensive use or major clashes. Many elephants favour one tusk over the other (effectively they are left- or right- tusked just as you are left- or right-handed). The most-used, or ‘master' tusk is usually shorter than the ‘servant' as it is worn-down by regular use. Often the most gentle bull elephants have the largest tusks in a population, as they are less likely to break them in a fierce clash. About one quarter of the tusk is housed within the elephant's skull, which has developed in order to be able to bear the weight of these huge teeth. http://www.sanparks.org/parks/kruger/elephants/about/tusks-ivory.php |
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| Taipan | Jan 10 2012, 10:46 PM Post #3 |
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Scientists Track African Elephants With Satellite Collars ScienceDaily (Mar. 18, 2008) — Scientists are tracking elephants using satellite collars in Botswana and Tanzania to document their movements and prevent human/elephant conflicts, which can be deadly. This research led to the founding of a nonprofit group "Elephants Without Borders" dedicated to building the World Elephant Conservation Center in Tanzania. In many regions of Africa, elephants are frequent visitors to farms and villages as they roam the landscape searching for food and water. This often brings them into conflict with humans. Researchers at the University of Massachusetts Amherst are tracking their movements through southern and eastern Africa using satellite collars in an effort to understand their ecology and help prevent these conflicts. “Elephant populations have been increasing in Botswana and Tanzania since the late 1980s, when protection measures stopped the ivory trade,” says Curtice Griffin of the department of natural resources conservation. “But human populations are also rising. Elephants graze in areas used by cattle and some raid farm fields, where they do a lot of damage in a short time. People have been killed when they try to chase elephants away or encounter them unexpectedly at night.” Additional researchers include doctoral student Alfred Kikoti, a native of Tanzania and Mike Chase of Botswana. The team recently founded “Elephants Without Borders (EWB),” a nonprofit group dedicated to understanding elephant ecology and behaviors and developing elephant conservation programs. EWB is launching a major fundraising campaign in 2008 to build the World Elephant Conservation Center in Tanzania. Chase and Griffin have tagged nearly 50 elephants in northern Botswana and Namibia, a vast wild area in the Kalahari Desert. “Elephants aren’t staying in the parks,” says Griffin. “We have followed them from Botswana into Zimbabwe and Zambia, and they are moving across the Caprivi Strip of Namibia into Angola, where tens of thousands of elephants roamed before being decimated by 25 years of civil war.” As they re-colonize southern Angola, the elephants move through mine fields without triggering the mines. Griffin suspects that their keen sense of smell helps them avoid the mines. Kikoti and Griffin have also fitted 20 elephants with satellite collars in northern Tanzania. “The problem of human-elephant conflict is worse in Tanzania,” says Griffin. “There are more people and farms. Elephants compete for water with Maasai cattle in the dry shrublands and raid large farms on the western slopes of Mt. Kilimanjaro. Griffin, Kikoti and Chase have documented the largest seasonal movements of elephants in Africa, and shown that the corridors used by elephants can be narrow and hemmed in by villages and roads, which elephants try to avoid. Communities and governments are encouraged to keep these ancient elephant paths open and establish wildlife conservation corridors free of huts and farms. This information is also important for community development. “Although having elephants near your village can be risky, they bring in tourists who bring in revenue,” says Griffin. “This is especially important in arid regions where there are few other sources of income. When communities realize they can earn money from tourists coming to see the elephants, they are much less likely to harm them when conflict occurs.” Attaching collars to elephants is a dangerous job. “We dart them with tranquilizers from a helicopter, and we usually dart the matriarch, the old female herd leader,” says Griffin. “If she is down, the rest of the herd stays away while we put on the collar. If we dart another herd member, the matriarch will sometimes circle back and try to kill us.” Elephants stay in breeding herds of about 18, so collaring one member lets the team monitor the entire herd. Collars are also attached to bull elephants. “When a bull is darted, the rest of the bulls could care less,” says Griffin. “In their search for mates, bulls have different movement patterns and indulge in risky behavior like traveling far from water. Bulls are fairly laid back compared to females with calves, but when they are in mutsh, a state of heightened breeding condition, they can be aggressive and dangerous.” Satellite collars used to track the elephants are produced in South Africa using global positioning units outfitted with extra protection to survive the rigors of elephant life. Periodic downloads of satellite GPS data via e-mail lets Griffin check on the herds from Massachusetts. Data are used to understand the seasonal movements of elephants and identify important corridors used as they make their way across the African landscape. Elephants Without Borders is currently being filmed in Africa by the British Broadcasting Corporation for a new series. Griffin regularly leads student trips from UMass Amherst to Africa, and will be returning in the summer of 2008 for an 18-day safari. This research is backed by the U.S. Fish and Wildlife Service and private donors. EWB works closely with governments and communities in Africa as well as private conservation organizations such as Conservation International, the African Wildlife Foundation and the Grumeti Fund.  Alfred Kikoti, a postdoctoral researcher at the University of Massachusetts Amherst, attaches a satellite collar to a tranquilized elephant. Adapted from materials provided by University of Massachusetts Amherst. http://www.sciencedaily.com/releases/2008/03/080318222509.htm |
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| Taipan | Jan 10 2012, 10:47 PM Post #4 |
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Elephant Memories May Hold Key To Survival ScienceDaily (Aug. 12, 2008) — A recent study by the Wildlife Conservation Society and the Zoological Society of London (ZSL) suggests that old female elephants—and perhaps their memories of distant, life-sustaining sources of food and water—may be the key to survival during the worst of times. In particular, experienced elephant matriarchs seem to give their family groups an edge in the struggle for survival in periods of famine and drought, according to a recently published paper in The Royal Society's Biology Letters. "Understanding how elephants and other animal populations react to droughts will be a central component of wildlife management and conservation," said Wildlife Conservation Society researcher Dr. Charles Foley, lead author of the study. "Our findings seem to support the hypothesis that older females with knowledge of distant resources become crucial to the survival of herds during periods of extreme climatic events." Dr Nathalie Pettorelli, ZSL researcher and co-author, added, "Climate change is expected to lead to a higher occurrence of severe drought in Africa and our study suggests that such extreme climatic events may act as a selection force on animal populations. As animals battle to cope certain individuals, such as these grand dames of the elephant kingdom, might become increasingly important." Specifically, the study examines patterns of calf mortality during the drought of 1993 in Tanzania's Tarangire National Park, the most severe drought in that region in the past 35 years. During a nine-month period of that year, sixteen out of 81 elephant calves in the three groups studied died, a mortality rate of 20 percent. The normal mortality rate of calves during non-drought years is a mere two percent. When compared with other data, researchers noted correlations in calf survivorship with the movements of the groups and, in particular, the ages of the female members within those groups. First, of the three elephant groups observed during the event, the two groups that left the park suffered lower mortality rates than the group that remained in the northern portion of the protected area. The researchers speculated that these elephants succeeded in finding sufficient food and water outside the protected area to keep themselves and their young alive. The group that stayed suffered 63 percent of the mortality for the year. Second, an examination of the ages of the individual elephants in the three herds was even more suggestive. The data indicated that the age of the mother elephants was an important predictor for calf survival. The two groups that left the park, presumably in search of food and water, had matriarchs that were ages 45 and 38 years of age respectively, whereas the group that remained had a matriarch that was only 33 years of age, the result of heavy poaching during the 1970's and 1980's that targeted older females with large tusks. Third, the researchers pointed out that the groups that left the park may have benefited from the specific experiences of their oldest matriarchs, which perhaps were able to draw upon memories of an earlier drought and how they survived it. The case is strengthened by the known life history of the oldest matriarchs in these groups, some of which were five years or older during the drought of 1958-61. The group that remained in Tarangire in 1993 had no individuals old enough to remember the event. "It's enticing to think that these old females and their memories of previous periods of trauma and survival would have meant all the difference," added Foley. "The data seem to support the speculation that the matriarchs with the necessary experience of such events were able to lead their groups to drought refugia." During the 1970s and '80s, many of Eastern Africa's largest elephants fell victim to waves of poachers who were eager to exploit the profitability of the black market for ivory. "Hopefully, this study underlines the importance of how crucial older matriarchs are to the health of elephant populations," added Foley. "Protecting the leaders of elephant herds will be even more important in what may be an increase in droughts due to climate change."  In a recent paper in The Royal Society's Biology Letters, conservationists with the Wildlife Conservation Society and the Zoological of London found that the oldest matriarch elephants may retain valuable memories of permanent sources of food and water and their that become crucial in times of drought. http://www.sciencedaily.com/releases/2008/08/080811200337.htm |
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| Taipan | Jan 10 2012, 10:49 PM Post #5 |
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When It Comes To Elephant Love Calls, The Answer Lies In A Bone-shaking Triangle ScienceDaily (Feb. 14, 2009) — Many a love-besotted soul has declared they would move the world for their true love, but how many actually accomplish that task in their quest to unite with a lover? Poets and romantics may argue the point, but research has shown that elephants issuing calls, including those of love—more precisely, females in estrus—produce not only audible sounds, but also low-frequency seismic vibrations that can travel through the near-surface soils for distances up to several kilometers. And though we humans may claim to feel our lover's call in our heart, soul or other organs of either physical or philosophical origin, most of us need said love call to caress the hair cells of our inner ears for it to register in what is arguably our most important love/sex organ—our brain. Elephants, however, have two highly developed additional sensory systems at their disposal, both of which can be used for detecting the potential mate's seismic signals (humans have both, too, just not tuned to using vibrations as communication). One system is bone conduction, in which the vibrations travel from the toe tips into the foot bones, then up the leg and into the middle ear. The other, somatosensory reception, involves vibration-sensitive cells in the bottom of the foot that send signals to the brain via nerves. Caitlin O'Connell-Rodwell, an ecologist and consulting assistant professor in otolaryngology at Stanford University School of Medicine, has been studying elephant communication for more than 15 years. During that time she's puzzled over which seismic sensing system elephants use most often in locating the source of a call. In her most recent field season last summer, she finally got an answer. "They are placing themselves in a way that best suits bone conduction, rather than somato-sensory reception," she said. O'Connell-Rodwell came to her conclusion by conducting a study of how male elephants respond to estrus calls from females. She played recorded calls through a speaker coupled with the ground and concealed in a pile of brush near a watering hole in Etosha National Park in Namibia. The speaker emitted both an acoustic and seismic signal. "The bulls would come in and then we would test them as they headed out of the water hole in different directions. They would always place themselves perpendicular to the direction the sound had traveled," she said. That orientation puts each of the elephant's ears at a different distance from the sound source and also creates the maximum possible difference in the distance between each of the elephant's ears and the source. That enhances their ability to distinguish the point of origin. This position was assumed by the elephants whether the signal was only seismic or both acoustic and seismic, suggesting that bone-conducted detection was the preferable method for detecting seismic frequencies. If the elephants preferred somatosensory reception, they would more likely align their front and back feet to create the greatest difference in distance from the source to each pair of feet. But perhaps that's where the trunk comes in. Every time the estrus recording was played, the bulls' behavior was the same, O'Connell-Rodwell said. "They stop, press their trunk on the ground and position themselves and turn the other way and place their trunk on the ground and do it again," she said. Pressing their trunk against the ground may improve the elephant's ability to use triangulation to locate a sound source, as using the trunk along with their (front) feet gives them the multiple (three) sensors needed for triangulating, or even front and back which would create a five sensor array. O'Connell-Rodwell had observed both male and female listening behavior in previous years but hadn't focused on the bone-conduction-versus-somatosensory-reception question. Although she had noticed that both males and females often oriented themselves in a manner that seemed more conducive to employing bone conduction, until this most recent study she hadn't tested how they responded when the sound effectively came from different locations. But she also noted differences in how bulls and cows behaved when listening. "The males seem to use their trunk in detecting vibrations much more than females," she said. "We don't know why that is yet." O'Connell-Rodwell used her observations of female behavior from previous field seasons as a basis for comparison with the males. She also noticed some behavioral differences in the bulls' reactions to the estrus calls. The bulls who responded in the characteristic fashion were all either males in musth—a condition in which levels of reproductive hormones skyrocket—or subadult males, as well as juveniles who were too young to go into musth. But adult males who were not in musth showed very little interest in the love calls of the cows and simply walked away from the water hole. The behavior of the adult males not in musth seemed to confuse any subadult males who were with them, O'Connell-Rodwell said. "The subadult would be torn between whether to go toward the estrus call or follow the adult male out," she said. "And they would end up following the adult out, but they kept turning back. The adult male wouldn't pay attention at all." O'Connell-Rodwell said more work remains to be done to unravel the social behavior of elephants, but she hopes to have more insights to offer soon. She has submitted a paper detailing aspects of male elephant society that is currently under review. But even with the uncertainties that remain—and really, shouldn't there always be an element of mystery when it comes to romance?—it seems clear that the key to finding love for those male elephants that want it lies in bone-jarring eternal triangulation.  When female elephants in estrus issue calls, they cause low-frequency seismic vibrations that male elephants, such as this one, can “listen” to with their feet and trunks. http://www.sciencedaily.com/releases/2009/02/090213161038.htm |
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| Taipan | Jan 10 2012, 10:50 PM Post #6 |
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The truth behind elephant brainpower  Inside the Elephant mind By Andrew Luck-Baker Page last updated at 16:48 GMT, Wednesday, 17 February 2010 Are elephants so smart that they can spot the difference when they hear people speaking different languages? Armed with a giant loudspeaker in the back of a land rover, it is a possibility that researchers have been exploring on the plains of Amboseli National Park in Kenya. They have also been trying to see if elephants can count lions and figure out the age of other elephants. Elephants do not have good eyesight but their sense of hearing is acute. It is much more sensitive than ours. The same is true for their sophisticated sense of smell. The scientists on the research team have been playing sounds or laying down scents which elephants would encounter in nature, but doing so in clever ways that reveal elephant knowledge and thought processes. Mental skills Dick Byrne, Professor of Evolutionary Psychology at St Andrew's University has studied the cognitive abilities of primates and has been carrying out the experiments with elephants at Amboseli, using different scents to probe mental skills. He said: "They've proved to have abilities which have only been found elsewhere in the great apes and humans. "We are a bit limited by how little we know about elephants, but the odd glimmers we get seem to be rather remarkable." One of the team's findings has been the elephants' ability to recognise many other individual elephants from the sound of their call. Karen McComb, an animal psychologist at the University of Sussex, UK, carried out a sound playback study designed to discover how many other elephants a single elephant might recognise from the sound of their calls. The specific call in question was a long, deep rumble known as the contact rumble. An elephant makes it to say, "I'm here. Where are you?". The low frequency message can be heard by other elephants several kilometres away. The contact call was played to numerous elephant family groups. It was calculated that elephant matriarchs were able to learn the identity of at least 100 other individual elephants by voice. Dr McComb's Sussex colleague, Graeme Shannon said it was akin to putting 100 people behind a wall in the far distance, getting each one to shout something and asking someone to identify each person correctly. Numerical skills There is also evidence from a study with animals in zoos in Japan that elephants have considerable numerical skills. Elephants have proved adept at recognising the difference between two quantities of objects as they were placed into buckets. It is a test which has also been done with a range of primates, including human children. According to Professor Byrne, elephants outperformed all those other species. "Their abilities didn't seem to be limited in quite the same way as monkeys, apes and children would be. "Most of us would find it much easier to discriminate two from one than from five and six... "But these effects didn't show up with the elephants. They are just as good at telling five from six as one from two."  Elephants can be alarmed when they hear the Maasai speaking The latest playback experiment by the Sussex team has been designed to see if Amboseli's elephants can discriminate between different human languages. The elephants commonly encounter speakers of three different human tongues as they move in and out of the national park's boundaries. There are the semi-nomadic cattle herders of the Maasai ethnic group, who speak a language called Maa. The animals also travel through land farmed by the Kamba people, who have their own language, and they hear English, which is spoken by the majority of tourists. Detecting whether they can tell languages apart depends on whether the elephants exhibit defensive or perhaps aggressive behaviour. According to Graeme Shannon, the animals are most likely to be alarmed when they hear the Maasai speaking. Amboseli's elephants and Maasai community are wary of each other. Sometimes elephants will kill Maasai cattle and, very occasionally, people. When this happens, young Maasai warriors will go out and spear an elephant to death in retaliation. Least threatening to the animals are the English-speaking tourists who just want to watch and take photos. The Sussex team have only just begun to play recordings of these different languages to the animals so it is too early to tell if elephants can tell the difference. However Dr Shannon recalls an incident when his assistant, Katito Sayialel, a Maasai who speaks Maa, was talking to the elephants. Katito said: "They were nervous, raising their heads." Yet when she spoke in Swahili they calmed down, relaxed and continued feeding. Dr Shannon said that as a scientist, he was a little cautious about saying it was definitely a response by the elephants but "there seemed to be something going on there". http://news.bbc.co.uk/2/hi/science/nature/8518831.stm |
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| Taipan | Jan 10 2012, 10:50 PM Post #7 |
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Africa Has Two Elephant Species, Genetic Analysis Confirms ScienceDaily (Dec. 21, 2010) — Contrary to the belief of many scientists (as well as many members of the public), new research confirms that Africa has two -- not one -- species of elephant. Scientists from Harvard Medical School, the University of Illinois, and the University of York in the United Kingdom used genetic analysis to prove that the African savanna elephant and the smaller African forest elephant have been largely separated for several million years. The researchers, whose findings appear online in PLoS Biology, compared the DNA of modern elephants from Africa and Asia to DNA that they extracted from two extinct species: the woolly mammoth and the mastodon. Not only is this the first time that anyone has generated sequences for the mastodon nuclear genome, but it is also the first time that the Asian elephant, African forest elephant, African savanna elephant, the extinct woolly mammoth, and the extinct American mastodon have been looked at together. "Experimentally, we had a major challenge to extract DNA sequences from two fossils -- mammoths and mastodons -- and line them up with DNA from modern elephants over hundreds of sections of the genome," says research scientist Nadin Rohland of the Department of Genetics at Harvard Medical School. According to David Reich, associate professor in the same department, "The surprising finding is that forest and savanna elephants from Africa -- which some have argued are the same species -- are as distinct from each other as Asian elephants and mammoths." Researchers only had DNA from a single elephant in each species, but had collected enough data from each genome to traverse millions of years of evolution to the time when elephants first diverged from each other. "The divergence of the two species took place around the time of the divergence of the Asian elephant and woolly mammoths," says Professor Michi Hofreiter, who specializes in the study of ancient DNA in the Department of Biology at York. "The split between African savanna and forest elephants is almost as old as the split between humans and chimpanzees. This result amazed us all." The possibility that the two might be separate species was first raised in 2001, but this is the most compelling scientific evidence so far that they are indeed distinct. Previously, many naturalists believed that African savanna elephants and African forest elephants were two populations of the same species, despite the significant size differences. The savanna elephant has an average shoulder height of 3.5 meters whereas the forest elephant has an average shoulder height of 2.5 meters. The savanna elephant weighs between six and seven tons, roughly double the weight of the forest elephant. DNA analysis revealed a wide range of genetic diversity within each species. The savanna elephant and woolly mammoth have very low genetic diversity, Asian elephants have medium diversity, and forest elephants have very high diversity. Researchers believe that this is due to varying levels of reproductive competition among males. "We now have to treat the forest and savanna elephants as two different units for conservation purposes," says Alfred Roca, assistant professor in the Department of Animal Sciences at the University of Illinois. "Since 1950, all African elephants have been conserved as one species. Now that we know the forest and savanna elephants are two very distinctive animals, the forest elephant should become a bigger priority for conservation purposes." This research was funded by the Max Planck Society and by a Burroughs Wellcome Career Development Award in Biomedical Science.  Top: Forest elephants (shown) in Africa have now been confirmed as a new species of elephant and have been distinguished from the larger savanna elephant in Africa. Bottom: Africa's savanna elephant (shown) is as different from Africa's forest elephant as Asian elephants are to mammoths, says a new study in PLoS Biology. -------------------------------------------------------------------------------- Journal Reference: Nadin Rohland, David Reich, Swapan Mallick, Matthias Meyer, Richard E Green, Nicholas J Georgiadis, Alfred L Roca, Michael Hofreiter. Genomic DNA Sequences from Mastodon and Woolly Mammoth Reveal Deep Speciation of Forest and Savanna Elephants. PLoS Biology, 2010; 8 (12): e1000564 DOI: [url]10.1371/journal.pbio.1000564[/url] http://www.sciencedaily.com/releases/2010/12/101221172244.htm |
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| Taipan | Jan 10 2012, 10:51 PM Post #8 |
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Older female elephants are wiser matriarchs By Victoria Gill Science and nature reporter, BBC News Page last updated at 09:23 GMT, Wednesday, 16 March 2011 Elephants pay close attention to their elders, especially when they hear the sound of an approaching predator, scientists have found. A research team monitored African elephants' reactions when they heard the sound of lions roaring. Groups of animals with older female leaders, or matriarchs, very quickly organised themselves into a defensive "bunch" when they heard a male lion. The findings are reported in the Royal Society journal Proceedings B.  Female elephants live in organised social groups The researchers already knew that older female elephants played very important roles in their social groups. But in this study, led by Karen McComb and Graeme Shannon from the University of Sussex, UK, scientists managed to put this to the test in a natural setting. The researchers first recorded lion roars, and separated their recordings into roars from male lions and those from female lions. They then used loudspeakers to play these sounds to 39 groups of female elephants in Amboseli National Park in Kenya. The groups with the oldest female leaders, or matriarchs, responded very quickly - and very appropriately - to the roars of male lions. The animals stopped to listen attentively, then bunched together to defend themselves. "Male lions present a very real threat [for elephants]," said Dr McComb. "They can be successful in bringing down a calf even when alone." Female lions, however, are unlikely to attack an elephant unless they are in large groups, and the researchers found that older female elephants were able to distinguish the sound of a male lion from a female.  Male lions occasionally hunt young elephants The older females' groups were much more likely to form this defensive bunch and even to aggressively approach the loudspeaker when they were played the roars of male lions. "Younger matriarchs didn't seem as bothered by male lions as they should have been," Dr McComb said. "We think its because they hadn't had sufficient exposure to that threat; lions don't [attack elephants] that often." She and her colleagues are now hoping to find out what exactly these experienced females do to trigger this co-ordinated response. "There are no loud vocal cues," she said. "We think they're quite subtle postural cues and we're also looking for soft vocalisations." Age and experience The team had found, in previous research, that these older - apparently wiser - matriarchs were better able to tell if other elephants were "friends" or intruders into their social groups. Josh Plotnik from the University of Cambridge, who has studied complex social behaviour in Asian elephants, said the results were "very exciting" and had implications for future studies of a variety of social species. "My experience with Asian elephants suggests a similar trend," he told BBC News. "Older females seem much more attuned to potential threats than younger females, which is most likely due to greater experience with a greater variety of environmental pressures." Dr McComb said she was surprised by the elephants' ability quickly and accurately to tell the difference between male and female lion roars. "The differences are very subtle," she said. "It's very difficult for us to tell them apart." She added that the study had demonstrated the need to conserve and protect these older animals. "These older individuals clearly have a vital role in how well elephants function in their social groups," she said. "This will have a wider effect on their longevity and reproductive success." http://news.bbc.co.uk/earth/hi/earth_news/newsid_9425000/9425590.stm |
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| Taipan | Jan 29 2012, 02:43 PM Post #9 |
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Killing of black and white rhinoceroses by African elephants in Hluhluwe-Umfolozi Park, South Africa "An unusual, but not unique, situation has arisen in HUP. African elephants, Loxodonta africana Blumenbach, 1797, have been killing both black (n = 5) and white rhinos (n = 58), mainly through tusk wounds made to the shoulder and chest area."  Source: Killing of black and white rhinoceroses by African elephants in Hluhluwe-Umfolozi Park, South Africa |
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| SameerPrehistorica | Feb 14 2012, 07:38 PM Post #10 |
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Here it is mentioned as ---- The height of a bull at his shoulder is about twelve feet. Alright..now that is good to see.When i made some animnal pictures, i use to put the African Elephant as 12feet.Mostly in some sites, it was like 11 or 11.5 or 12 feet.I know it is somewhat taller than Bull Asian Elephant which is 10 feet tall.But the onething i can't understand is, As far as i have seen in most size comparison image of Some big animal, they put the African Elephant as 10 feet tall.Anyway.. |
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