ELEPHANT

Facts

Three living species are currently recognised: the African Bush Elephant (Loxodonto Africana), the African Forest Elephant (L. Cyclotis), and the Asian Elephant (Elephas maximus). They are the only surviving members of the family Elephantidae and the order Proboscidea.

They are herbivores, and they stay near water when it is accessible. They are considered to be keystone species, due to their impact on their environments. Elephant have a fission-fusion society, in which multiple family groups come together to socialise. Females (cows) tend to live in family groups, which can consist of one female with her calves or several related females with offspring. The leader of a female group, usually the oldest cow, is known as the matriarch.

Males (bulls) leave their family groups when they reach puberty and may live alone or with other males. Adult bulls mostly interact with family groups when looking for a mate. They enter a state of increased testosterone and aggression known as musth, which helps them gain dominance over other males as well as reproductive success. Calves are the centre of attention in their family groups and rely on their mothers for as long as three years. Elephant can live up to 70 years in the wild. They communicate by touch, sight, smell, and sound; Elephant use infrasound and seismic communication over long distances. Elephant intelligence has been compared with that of primates and cetaceans.. They appear to have self-awareness, and possibly show concern for dying and dead individuals of their kind.

African Bush Elephant and Asian Elephant are listed as endangered and African Forest Elephant as critically endangered by the International Union for Conservation of Nature (IUCN). One of the biggest threats to Elephant populations is the ivory trade, as the animals are poached for their ivory tusks. Other threats to wild Elephant include habitat destruction and conflicts with local people. Elephant are used as working animals in Asia. Elephant have an iconic status in human culture and have been widely featured in art, folklore, religion, literature, and popular culture.

The skeleton is made up of 326–351 bones. The vertebrae are connected by tight joints, which limit the backbone’s flexibility. African Elephant have 21 pairs of ribs. The skull contains air cavities (sinuses) that reduce the weight of the skull while maintaining overall strength. These cavities give the inside of the skull a honeycomb-like appearance. By contrast, the lower jaw is dense. The cranium is particularly large and provides enough room for the attachment of muscles to support the entire head. The skull is built to withstand great stress, particularly when fighting or using the tusks. The brain is surrounded by arches in the skull, which serve as protection. Because of the size of the head, the neck is relatively short to provide better support. Elephant are homeotherms and maintain their average body temperature at ~ 36 °C (97 °F), with a minimum of 35.2 °C (95.4 °F) during the cool season, and a maximum of 38.0 °C (100.4 °F) during the hot dry season.

Elephant ear flaps, or pinnae, are 1–2 mm (0.039–0.079 in) thick in the middle with a thinner tip and supported by a thicker base. They contain numerous blood vessels called capillaries. Warm blood flows into the capillaries, releasing excess heat into the environment. This effect is increased by flapping the ears back and forth. Larger ear surfaces contain more capillaries, and more heat can be released. Of all the Elephant, African Bush Elephant live in the hottest climates and have the largest ear flaps. The ossicles are adapted for hearing low frequencies, being most sensitive at 1 kHz.

Lacking a lacrimal apparatus (tear duct), the eye relies on the harderian gland in the orbit to keep it moist. A durable nictating membrane shields the globe. The animal’s field of vision is compromised by the location and limited mobility of the eyes. Elephant are dichromats and they can see well in dim light but not in bright light.

The elongated and prehensile trunk, or proboscis, consists of both the nose and upper lip, which fuse in early foetal development. This versatile appendage contains up to 150,000 separate muscle fascicles, with no bone and little fat. These paired muscles consist of two major types: superficial (surface) and internal. The former are divided into dorsal, ventral and lateral muscles, while the latter are divided into transverse and radiating muscles. The muscles of the trunk connect to a bony opening in the skull. The nasal septum consists of small elastic muscles between the nostrils, which are divided by cartilage at the base. A unique proboscis nerve – a combination of the maxillary and facial nerves – lines each side of the appendage.

As a muscular hydrostatic, the trunk moves through finely controlled muscle contractions, working both with and against each other. Using three basic movements: bending, twisting, and longitudinal stretching or retracting, the trunk has near unlimited flexibility. Objects grasped by the end of the trunk can be moved to the mouth by curving the appendage inward. The trunk can also bend at different points by creating stiffened “pseudo-joints”. The tip can be moved in a way similar to the human hand. The skin is more elastic on the dorsal side of the Elephant trunk than underneath; allowing the animal to stretch and coil while maintaining a strong grasp. The African Elephant have two finger-like extensions at the tip of the trunk that allow them to pluck small food.

The trunk’s extreme flexibility allows it to forage and wrestle other Elephant with it. It is powerful enough to lift up to 350 kg (770 lb), but it also has the precision to crack a peanut shell without breaking the seed. With its trunk, an Elephant can reach items up to 7 m (23 ft) high and dig for water in the mud or sand below. It also uses it to clean itself. Individuals may show lateral preference when grasping with their trunks: some prefer to twist them to the left, others to the right. Elephant trunks are capable of powerful siphoning. They can expand their nostrils by 30%, leading to a 64% greater nasal volume, and can breathe in almost 30 times faster than a human sneeze, at over 150 m/s (490 ft/s). They suck up water, which is squirted into the mouth or over the body. They will also sprinkle dust or grass on themselves. When underwater, the Elephant uses its trunk as a snorkel.

The trunk also acts as a sense organ. Its sense of smell may be four times greater than a bloodhound’s nose. The infraorbital nerve, which makes the trunk sensitive to touch, is thicker than both the optic and auditory nerves. whiskers grow all along the trunk, and are particularly packed at the tip, where they contribute to its tactile sensitivity. Unlike those of many mammals, such as cats and rats, Elephant whiskers do not move independently (“whisk”) to sense the environment; the trunk itself must move to bring the whiskers into contact with nearby objects. Whiskers grow in rows along each side on the ventral surface of the trunk, which is thought to be essential in helping Elephant balance objects there, whereas they are more evenly arranged on the dorsal surface. The number and patterns of whiskers are distinctly different between species.

Damaging the trunk would be detrimental to an Elephant’s survival, although in rare cases, individuals have survived with shortened ones. One trunkless Elephant has been observed to graze using its lips with its hind legs in the air and balancing on its front knees. Floppy trunk syndrome is a condition of trunk paralysis recorded in African Bush Elephant and involves the degeneration of the peripheral nerves and muscles. The disorder has been linked to lead poisoning.

Elephant usually have 26 teeth: the incisors, known as the tusks; 12 deciduous premolars; and 12 molars. Unlike most mammals, teeth are not replaced by new ones emerging from the jaws vertically. Instead, new teeth start at the back of the mouth and push out the old ones. The first chewing tooth on each side of the jaw falls out when the Elephant is two to three years old. This is followed by four more tooth replacements at the ages of four to six, 9–15, 18–28, and finally in their early 40s. The final (usually sixth) set must last the Elephant the rest of its life. Elephant teeth have loop-shaped dental ridges, which are more diamond-shaped in African Elephant.

Elephant skin is generally very tough, at 2.5 cm (1 in) thick on the back and parts of the head. The skin around the mouth, anus, and inside of the ear is considerably thinner. Elephant are typically grey, but African Elephant look brown or reddish after rolling in coloured mud. Calves have brownish or reddish hair, with the head and back being particularly hairy. As Elephant mature, their hair darkens and becomes sparser, but dense concentrations of hair and bristles remain on the tip of the tail and parts of the head and genitals. Normally, the skin of an Asian Elephant is covered with more hair than its African counterpart. Their hair is thought to help them lose heat in their hot environments.

Although tough, Elephant skin is very sensitive and requires mud baths to maintain moisture and protection from burning and insect bites. After bathing, the Elephant will usually use its trunk to blow dust onto its body, which dries into a protective crust. Elephant have difficulty releasing heat through the skin because of their low  surface area to volume ratio, which is many times smaller than that of a human. They have even been observed lifting up their legs to expose their soles to the air. Elephant only have sweat glands between the toes, but the skin allows water to disperse and evaporate, cooling the animal. In addition, cracks in the skin may reduce dehydration and allow for increased thermal regulation in the long term.

To support the animal’s weight, Elephant limbs are positioned more vertically under the body than in most other mammals. The long bones of the limbs have cancellous bones in place of medullary cavities. This strengthens the bones while still allowing haematopoeisis (blood cell creation). Both the front and hind limbs can support Elephant weight, although 60% is borne by the front. The position of the limbs and leg bones allows an Elephant to stand still for extended periods of time without tiring. The circular feet of an Elephant have soft tissues, or “cushion pads” beneath the manus or pes, which allow them to bear the animal’s great mass. They appear to have a sesamoid, an extra “toe” similar in placement to a Giant Panda’s extra “thumb”, that also helps in weight distribution. As many as five toenails can be found on both the front and hind feet.

Elephant can move both forward and backward, but are incapable of trotting, jumping or galloping. They can move on land only by walking or ambling: a faster gait similar to running. In walking, the legs act as pendulums, with the hips and shoulders moving up and down while the foot is planted on the ground. The fast gait does not meet all the criteria of running, since there is no point where all the feet are off the ground, although the Elephant uses its legs much like other running animals, and can move faster by quickening its stride. Fast-moving Elephant appear to ‘run’ with their front legs, but ‘walk’ with their hind legs and can reach a top speed of 25 km/h (16 mph). At this speed, most other quadrupeds are well into a gallop, even accounting for leg length. Spring-like kinetics could explain the difference between the motion of Elephant and other animals. The cushion pads expand and contract, and reduce both the pain and noise that would come from a very heavy animal moving. Elephant are capable swimmers: they can swim for up to six hours while completely waterborne, moving at 2.1 km/h (1 mph) and traversing up to 48 km (30 mi) continuously.

The brain of an Elephant weighs 4.5–5.5 kg (10–12 lb) compared to 1.6 kg (4 lb) for a human brain. It is the largest of all terrestrial mammals. While the Elephant brain is larger overall, it is proportionally smaller than the human brain. At birth, an Elephant brain already weighs 30–40% of its adult weight.

The throat of an Elephant appears to contain a pouch where it can store water for later use. The larynx of the Elephant is the largest known among mammals. The vocal folds are anchored close to the epiglottis base. When comparing an Elephant vocal folds to those of a human, an Elephant are proportionally longer, thicker, with a greater cross-sectional area. In addition, they are located further up the vocal tract with an acute slope.

The heart of an Elephant weighs 12–21 kg (26–46 lb). Its apex has two pointed ends, an unusual trait among mammals. In addition, the ventricles of the heart split towards the top, a trait also found in sirenians. When upright, the Elephant heart beats around 28 beats per minute and actually speeds up to 35 beats when it lies down. The blood vessels are thick and wide and can hold up under high blood pressure.

Less than half of an Elephant’s food intake gets digested, despite the process lasting a day. Elephant kidneys can produce more than 50 litres of urine per day.

Elephant are herbivorous and will eat leaves, twigs, fruit, bark, grass, and roots. African Elephant mostly browse, while Asian Elephant mainly graze. They can eat as much as 300 kg (660 lb) of food and drink 40 L (11 US gal) of water in a day. Elephant tend to stay near water sources. They have morning, afternoon, and nighttime feeding sessions. At midday, Elephant rest under trees and may doze off while standing. Sleeping occurs at night while the animal is lying down. Elephant average 3–4 hours of sleep per day. Both males and family groups typically move no more than 20 km (12 mi) a day, but distances as far as 180 km (112 mi) have been recorded in the Etosha region of Namibia. Elephant go on seasonal migrations in response to changes in environmental conditions. In northern Botswana, they travel 325 km (202 mi) to the Chobe River after the local waterholes dry up in late August.

Their habit of uprooting trees and undergrowth can transform savannah into grasslands; smaller herbivores can access trees mowed down by Elephant. When they dig for water during droughts, they create waterholes that can be used by other animals. When they use waterholes, they end up making them bigger. Because most of the food Elephant eat goes undigested, their dung can provide food for other animals, such as dung beetles and monkeys. Elephant can have a negative impact on ecosystems.

Elephant typically coexist peacefully with other herbivores, which will usually stay out of their way. Some aggressive interactions between Elephant and rhinoceros have been recorded. The size of adult Elephant makes them nearly invulnerable to predators. Calves may be preyed on by Lion, Spotted Hyena and Wild Dog in Africa. The Lion of Savuti, Botswana, have adapted to hunting Elephant, targeting calves, juveniles or even sub-adults.

Elephant are generally gregarious animals. African Bush Elephant in particular have a complex, stratified social structure. Female Elephant spend their entire lives in tight-knit matrilineal family groups. They are led by the matriarch, who is often the eldest female. She remains leader of the group until death or if she no longer has the energy for the role. When her tenure is over, the matriarch’s eldest daughter takes her place instead of her sister (if present). One study found that younger matriarchs take potential threats less seriously. Large family groups may split if they cannot be supported by local resources.

Adult males live separate lives. As he matures, a bull associates more with outside males or even other families. When males permanently leave, they either live alone or with other males. The former is typical of bulls in dense forests. A dominance hierarchy exists among males, whether they are social or solitary. Dominance depends on age, size, and sexual condition. Male Elephant can be quite sociable when not competing for mates and form vast and fluid social networks. Older bulls act as the leaders of these groups. The presence of older males appears to subdue the aggression and “deviant” behaviour of younger ones. The largest all-male groups can reach close to 150 individuals. Adult males and females come together to breed. Bulls will accompany family groups if a cow is in oestrus.

The main characteristic of a bull’s musth is a fluid discharged from the temporal gland that runs down the side of his face. Behaviours associated with musth include walking with a high and swinging head, non-synchronous ear flapping, picking at the ground with the tusks, marking, rumbling, and urinating in the sheath. The length of this varies between males of different ages and conditions, lasting from days to months. Males become extremely aggressive during musth. In contests between musth and non-musth individuals, musth bulls win the majority of the time, even when the non-musth bull is larger. A male may stop showing signs of musth when he encounters a musth male of higher rank. Those of equal rank tend to avoid each other. Agonistic encounters typically consist of threat displays, chases, and minor sparring. Rarely do they full-on fight.

Elephant are polygynous breeders, and most copulations occur during rainfall. An oestrous cow uses pheromones in her urine and vaginal secretions to signal her readiness to mate. The oestrous cycle of a cow lasts 14–16 weeks, with the follicular phase lasting 4–6 weeks and the luteal phase lasting 8–10 weeks. Cows over 45–50 years of age are less fertile.

Gestation in Elephant typically lasts between one and a half and two years and the female will not give birth again for at least four years. Births tend to take place during the wet season. Typically, only a single young is born, but twins sometimes occur. Calves are born roughly 85 cm (33 in) tall and with a weight of around 120 kg (260 lb). They are precocial and quickly stand and walk to follow their mother and family herd. A newborn calf will attract the attention of all the herd members. Adults and most of the other young will gather around the newborn, touching and caressing it with their trunks. For the first few days, the mother limits access to her young. For the first few days, the newborn is unsteady on its feet and needs its mother’s help. It relies on touch, smell, and hearing, as its eyesight is less developed. With little coordination in its trunk, it can only flop it around which may cause it to trip. When it reaches its second week, the calf can walk with more balance and has more control over its trunk. After its first month, the trunk can grab and hold objects, but still lacks sucking abilities, and the calf must bend down to drink. It continues to stay near its mother as it is still reliant on her. For its first three months, a calf relies entirely on its mother’s milk, after which it begins to forage for vegetation and can use its trunk to collect water. At the same time, there is progress in lip and leg movements. By nine months, mouth, trunk and foot coordination are mastered. Suckling bouts tend to last 2–4 min/hr for a calf younger than a year. After a year, a calf is fully capable of grooming, drinking, and feeding itself. It still needs its mother’s milk and protection until it is at least two years old. Suckling after two years may improve growth, health and fertility. Adulthood starts at about 18 years of age in both sexes. Elephant have long lifespans, reaching 60–70 years of age.

Elephant produce several vocalisations—some of which pass though the trunk for both short and long range communication. This includes trumpeting, bellowing, roaring, growling, barking, snorting and rumbling. Elephant can produce infrasonic rumbles. For African Elephant, calls range from 15 to 35 Hz with sound pressure levels as high as 117 dB, allowing communication for many kilometres, possibly over 10 km (6 mi).