Understanding elephants

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Every visitor to the African bush wants to see an elephant. Alongside their intelligence, intense social ties, vulnerability to emotion and phenomenal memories, they’re physically extraordinary too, as Travel Africa reveals.

Size – the secret to survival

The elephant’s gargantuan proportions determine almost everything physical about it. Size has enabled it to survive over the millennia.

Depending on maturity, African bull elephants stand between three and four metres at the shoulder and weigh between five and six tons. That’s more than the combined weight of 100 human adults!

Possibly the largest was an Angolan bull that stood at just over 4m, was 9.8m long and supposedly topped the scales at 10.9 tons. Its skin alone weighed 1.8 tons and was later mounted at the Washington museum. Another, said by rangers to be nearly as big, was Zhulamati (Shangaan for “taller than the trees”). He had one tusk so long it rubbed on the sands of Zimbabwe’s Gonarezhou Reserve. Doddiburn, the well-known bull in the Bulawayo Museum (also in Zimbabwe), is thought to be the second largest mounted specimen in the world. He measured over 3m at the shoulder, weighed 5.5 tons and carried tusks over 40kg each.

However, most elephants roaming in the plains of Africa today are of a lesser stature, as are the females of the species – they weigh in between 2.7 and 3.5 tons and stand about 3m at the shoulder.

To cope with this bulk, the elephant’s skeleton is extremely rigid and his movement stiff. The short, thick, muscular neck, needed to support the elephant’s gigantic head and tusks, is very limited in its movement.

Muscle power alone won’t hold the tonnage, so its legs are stout columns of nearly solid bone positioned almost vertically beneath and on the corners of the torso – like the legs of a table. Although it cannot run it walks efficiently at about 5km/h and can ‘speed stride’ at about 40km/h.

Each step sends a three ton shock jolting through the leg, but a wedge of special fatty tissue in the foot absorbs the impact. This fleshy pad enables the sole to splay on landing, thus distributing the animal’s weight over a larger surface area.

Standing, the elephant’s bulk rests mainly on the thick cushion behind the toes. The latter point straight forward but are fairly rudimentary and cased in a common skin. Not surprisingly, elephants cannot jump and a ditch wider than a step is an impenetrable barrier.

Ivory – the “white gold” of rapacious humans

Most African elephants, male and human, sport tusks, which are important tools for chiselling, debarking, digging, rooting, levering, breaking, ripping, displaying as weaponry and stabbing.

Tusks are, in fact, modified incisor teeth, not canines as might be expected. A large part is embedded in the skull but measurements along the curve from tip to point of entry have recorded lengths of 3.5m. Most animals sport less than half that. Likewise, whilst a tusk weight of 106.8kg was once recorded, the majority of elephants carry considerably less than 50kg per tusk.

Tusks continue to grow about 10cm per year throughout an elephant’s life, so broken tips are replaced. However, continuous wearing down and breakages mean they never achieve full potential length. The tusks of the jumbos that dig salts in Uganda’s Mount Elgon caves, for example, are particularly short and stumpy as a result of working the hard cave walls.

The tusks of cows tend to be more slender than those of bulls. A few animals have been found to sport four tusks, but more common are tuskless specimens.

Tusklessness may be a natural selection process evolved as a way to combat poaching. Genetic tusklessness seems to be on the increase. In some parts of Africa up to a third of calves born will never carry these useful tools. In less than half a century, mankind has perhaps forcibly accelerated a change that should take thousands of years of evolution. The consequences of tusklessness on an elephant’s behaviour, especially feeding, remain to be seen. However, in the Zambezi Valley, where tusklessness has increased, the animals are noticeably more belligerent.

In cross-section, the tusk exhibits lines which radiate from the centre like a star – the only mammal tooth to do so. This feature makes it more valuable than the tusks from animals such as the warthog: in texture, the elephant tusk is soft enough to carve yet hard enough to buff and shine.

Tusk excellence as a carving medium or prestige value as a hunting trophy are not the only reasons for killing elephants. In the past, powdered ivory shavings featured in enema preparations, whilst ivory shavings were used as a jelly-making ingredient in 19th century England. Burnt ivory, sometimes called black velvet, was used to colour paints, inks and human hair.

Carved ivory thrones are mentioned in the Bible. Kings and Queens throughout history also esteemed them. Most notable, perhaps, was that laid with gold upon which Suleiman the Magnificent sat. Tutankhamen’s tomb housed a casket inlaid with over 40,000 pieces of ivory and Caligula built an ivory stable for his horse. In the 20th century, bagpipe joints, piano keys, billiard balls, rosary beads, and a host of figurines and trinkets have been fashioned from ivory.

The eating machine

The elephant is a biological eating machine with a colossal appetite: up to 200kg of vegetation may be consumed each day.

Tender new grass is relished but amongst the hundreds of different plant species on their menu, staples include leaves, reeds, seed pods and herbs. Living in groups, they cannot afford to be discerning diners: there just wouldn’t be enough to go round. The elephant’s diet, therefore, comprises a lot of low quality food – tough tree bark and coarse shrubs.

Elephants will graze by preference, but this is only possible when grasses are plentiful (in the moist growth phase). When grasses dry out and become fibrous, the animals gradually switch back to browse. They are particularly partial to fruits such as vegetable ivory and wild almond.

Being able to stretch up to 6m, elephants can pluck fruit and leaves from treetops beyond a giraffe’s reach. They are connoisseurs of agricultural crops, particularly favouring race, maize, millet, sugarcane, palms, bananas and fruits – often staple foods of local communities.

To get the nourishment they need, elephants spend up to 18 hours each day eating. This leaves only a few hours in which to sleep at night. This they normally do standing up. Bulls have been seen propping themselves against termite mounds; calves generally lie down to sleep.

The elephant chews its food by grinding the lower jaw against the upper, using a forward and backward motion. Masticating large amounts of rough vegetation means phenomenal wear and tear for teeth.

To cope with this, the elephant has a conveyor belt of molars made of a series of flat, transverse plates, each growing independently from its own root. The whole is joined together by cement to form great blocks of enamel and dentine about 30cm long. As one set wears down, another larger set moves forward to replace it (no more than two sets being in use at any one time). The sixth and last pair, weighing up to 4kg each, comes into place at about 40 years of age. When finally worn out, about 20 years later, the animal dies of a combination of old age, malnutrition and starvation.

The elephant’s massive rigid frame means that it does not lower its head to eat. It relies, therefore on its flexible trunk to graze the grasses below and browse the boughs above.

The trunk evolved from a fusion of the nose and upper lip muscles into a single organ of great mobility, over 5m long. It is the most versatile limb in nature, even more dextrous than the human hand.

This boneless extension contains over 100,000 interlacing muscle units, some running longitudinally and others radiating outward from the centre. It ends with two opposable finger/thumb-like tips (the Asian elephant only has one). Here it bristles with thousands of whiskers and is sensitive to the slightest touch. Each bristle is attached to a single nerve that travels the entire length of the trunk before feeding directly into the brain. This makes the tip 10 times more sensitive than a human finger.

With such equipment, the elephant can pick up a single peanut, strip leaves from a stem in one sweep, pull plants from the ground and convey food and water to its mouth.

The trunk, however, is not just the elephant’s fork and spoon. It can siphon with suction strong enough to draw up nine litres of water in one go and then spray it (or dust) over its body.

To get rid of ticks and parasites, elephants bathe themselves at least once a day if possible. Trunkfuls of water are blown first behind the ears, then along the flanks, between the legs and on top of the head. A mud wallow and/or dust baths follows. The latter leaves them tinted with the colour of their surroundings.

The trunk can also produce a trumpeting, bloodcurdling scream that can be heard miles away. It can be extended, retracted, bent, twisted and turned in almost any direction, its sense allowing it to determine the shape, texture, temperature and scent of any object.

An elephant’s trunk is a barometer to its mood: it hardly ever stays still. When it’s curled up, the animal is relaxed (each individual has his own idiosyncratic way of doing this). When the trunk is held high, the elephant is alert; when it is tensed up the beast is feeling distressed, and it is curled back when danger is sensed. The ancient Romans considered the trunk a culinary delicacy.

At the fount of life

To aid digestion, elephants need up to 270 litres of water a day. This is sucked into the trunk, which is then curled and tipped to release the contents into the mouth, a technique acquired only after about six months of age – and plenty of practice!

When surface water is not within half a day’s march, elephants will use their tusks and trunks to dig wells, usually in the dry riverbeds or where they sense some sub-surface deposits. These wells, normally about a metre deep, enable many other creatures to survive in drought areas. Animal action around the well enlarges it.

Elephants dominate at waterholes, sometimes driving off and occasionally even killing intruders – buffalo and giraffe included. Here they drink, then enjoy bathing and mud wallows, after they often shower themselves with dust and rub against trees and boulders. All this helps remove ticks and other pests, keeps the skin in good condition and aids cooling. The pans are broadened as tons of soil are removed on the backs of elephants.

Elephants can swim well, maintaining a speed of about 1.5km/h for up to six hours. Amazingly, in the late 1970s, two bulls swam from Zimbabwe’s Spurwing Island across Lake Kariba to Kariba town, a distance of at least 25km. These 20-year-olds took turns to rest, one placing his forelegs on the haunches of his companion in front. Apparently their 24-hour-long trip followed an old elephant migration trail that had been covered by the lake for 25 years!

The elephants’ remarkable proficiency in water is cited in support of research evidence that they were originally water creatures. Studies of embryos show that the lungs, kidneys and testes of the elephant all develop in a manner similar to many aquatic animals.

Learn more about elephants in our themed wildlife issue, available here.

Biological air-con

Bathing and squirting water behind the ears certainly helps to cool the body, but it’s not enough. Because they are large, elephants have a small body surface area relative to their weight, and they don’t have sweat glands as they would lose too much vital body water. So under the baking savannah or desert sun, when temperatures can soar to 50°C, they are liable to cook.

To combat the overheating problem, elephants are endowed with two ultra-efficient heat-dispersing mechanisms: their ears and their skin.

The African elephant’s ears are larger than those of the Asian elephant’s, and when spread in display produce a frightening 3m front. They make up one-fifth of the elephant’s total surface area. The ears are covered with paper-thin ‘skin’ and the rear are supplied with hundred of blood vessels. These are close to the surface and as the ears are rhythmically flapped, the circulating blood is cooled.

Elephants often squirt water behind the ears to accelerate the evaporative process. Every 20 minutes, an elephant’s entire blood supply, nearly 680 litres, passes through the ear’s intricate network of veins and capillaries.

An African elephant’s skin, despite being about 2.5cm thick, is quite sensitive. It is also almost hairless and more wrinkled than that of the Asian elephant. It is pitted with deep channels and pockets, whereas that covering an Asian elephant is more like an open honeycomb. In effect, the skin is almost twice as big as it needs to be: stretched out, it would cover about 24 sq m. The wrinkling enables the elephant to hold more than 10 times the amount of water that would remain on a flat surface, and to dissipate heat more efficiently.

Another cooling device lies deep inside the elephant’s throat, where a special pouch holds water that can be siphoned out and sprayed over the baking body when far from a waterhole.

Making sense of the world

Elephants cannot turn their heads much to the side. Their eyes, small and hidden behind long bushy eyelashes, are also buried in folds of skin thus further limiting their vision.

To make matters worse, the eye is made up mainly of rods (the retina’s light collecting cells). Whilst these function well in low light, they get overloaded in bright sunshine and their large number restricts the number of cones (cells that process colour and focal depth). As a consequence, elephants don’t register detail. The view may be dim but shape, gait and smell – a much more powerful sense for bringing the world into focus – identify individuals.

Elephants live in a world of complex odours that lie beyond human senses. The nasal lining of the trunk contains 20 million scent receptors – over three times those possessed by humans. These feed the brain, where nearly two-thirds of its capacity is used in processing odours.

Thus the elephant creates a discerning olfactory picture, one that is also very discriminatory: elephants can detect and identify particular individuals from some distance, and interpret emotional states such as excitement, fear, stress and sexual receptivity.

All elephants secrete a thick, pungent substance called temporin. Excitement or fear stimulates its flow from slit-like temporal glands (modified tear glands) located either side of the face midway between eye and ear.

When this gland functions, the forehead swells, a dark oily substance oozes conspicuously down the side of the face, and there is a marked rise in aggressive behaviour. The odour varies individually and is secreted year round by cows but only by bulls in musth, a Hindi word meaning madness. It first appears at about two years of age, peaks in males at about 35 years and finally subsides around the animal’s half century.

The most pungent of elephant odours, easily detectable even by humans, is that of a bull in musth. There is a marked rise in the production of the male hormone, testosterone, the testes being carried internally next to the kidneys. A bull’s dangling penis assumes a green hue as it constantly dribbles, leaving a trail of extremely acrid urine.

Only when thus ready will the bull seek out a mate within a family group. Bulls come into musth at different times of the year, so cows who come into season for a few days every three months (if not pregnant or lactating) can be serviced.

The mating game

Cows reach sexual maturity around the age of 12, mate and are already first-time mothers by 16. Females in season, identified by the loud oestrus rumbles they utter, are tested for readiness by males who put their trunks to the cow’s vulva and collect and taste a sample of her urine. In the palate is a special organ sensitive to the hormonal content of the urine and this to the cow’s reproductive state.

When two musth males contest a female, an intense, aggressive battle ensues, forehead to forehead. (Male foreheads are more rounded than those of females.) The confrontation may last five or six hours, the victorious bull being rewarded with ready compliance of the cow. By co-operating with the strongest specimen around, she ensures the quality of her offspring.

Cows can outpace bulls if they wish, and do so if approached by an unwelcome suitor. Having chosen a male, a cow stands still when touched – usually by the bull laying his trunk along her back. He then mounts by heaving himself onto his hind legs and squatting slightly as he works his forelegs up the female’s back. By hooking up his S-shaped penis, he enters her. He is unable to thrust with his body but his penis moves independently within her and copulation lasts no longer than a minute.  The act sometimes induces great excitement amongst the herd but often is ignored.

Elephants generally part after mating but occasionally a couple will consort for a time, paying close attention to each other and excluding others from any intimacy. They may even separate from the herd. If she has conceived, it will be 22 months until she gives birth.

Young at heart

Cows give birth standing up. The calf is a pinkish-grey colour, is hairy and weighs about 110kgs.

During birth, other females from the herd often attend the mother. Subsequently these ‘midwives’ generally adopt a communal responsibility towards the upbringing of that youngster.

At birth the calf is extremely vulnerable to predators, so using her foot, the mother gently prods him to rise and join the herd. It may be an hour before he takes his first faltering steps.

The calf suckles from the pair of teats between the mother’s forelegs, sometimes standing on its hind legs to reach them. For the first year, calves can pass under their mother’s body. They are normally weaned at 18-24 months but may continue to suckle until after their fourth or fifth year.

Young calves stay in constant contact with their ever-protective mothers and remain dependent upon family until well into their teens. The emotional bond between mother and child seems as strong as in humans.

Baby elephants are born with few inter-connections between brain cells and therefore lack a number of skills vital to survival. As with humans, this sets the species apart as the brain is more malleable and has a large capacity for learning.

Survival skills – how and what to eat and drink, how to bathe and dust, and how to behave – are taught by the mother. In a world of exciting discoveries, learning to control the trunk is a major challenge requiring two years to accomplish.

Learning social skills is also vital. The complex structure of elephant society is founded upon a subtle hierarchy determined principally by age. Learning one’s place, acceptable manners and how to show respect for elders (particularly the matriarch) is as fraught with difficulties as it is for human children.

The elephant’s extended period of learning indicates a measure of intelligence that enables it to develop skills it uses in circuses and when working in elephant-back safaris. Its capacity to comprehend may even equate with that of the great apes.

However, in proportion to body size, the elephant’s brain is small, though its temporal lobes are abnormally large and well developed – hence their remarkable memories. Wisdom appears to be well respected in elephant society, allowing matriarchs to retain leadership after menopause.

The matriarch

The matriarch is the linchpin of elephant society. She determines the nature, structure and ethos of the family unit. She decides where the family will go each day, when and where they will pause to eat and drink, and what they will do in times of trouble or danger.

Matriarchs supply the family unit with an historical memory of feeding grounds and the location of seasonally edible fruits and other dispersed features in the environment. The group’s survival in times of drought is very dependent upon her ability to remember the location of water, sometimes last visited several decades before.

Little is known about how elephants can recall such experiences. Possibly by memorising basic landscape features, the matriarch may have created a mental map. Another theory is that she navigates using a complex combination of sun and star signs and electromagnetic fields.

Happy families

The basic family unit usually consists of several related females and their offspring, all under the control of the matriarch. Families seldom exceed 10-15 animals, a subgroup led by a sister or close relation of the matriarch separating and going its own way when the group gets too large.

In places like the Serengeti, Selous, Tsavo, Luangwa and Hwange National Parks, herds numbering hundreds, occasionally up to a thousand animals, sometimes gather when food is abundant. Family groups within the gathering retain their identity whilst bull herds circulate. These loose-knit groups contain youngsters of 12-15 years of age who engage in mock battles or ‘jousting’ – a ritual that helps establish their position within the group hierarchy.

Within the family, members often touch one another. They sniff each other’s temporal glands on meeting and greeting, and the lower-ranking individual usually inserts the tip of his trunk into the other’s mouth. This enables him to assess mood, whilst also showing respect. On meeting, two unfamiliar elephants will often exchange a trunk shake, and thereby assess each other’s size and strength. Exploring each other’s bodies, they gain a mental image that sight could not supply.

When two family groups reunite after a period of separation, their tactile greetings are often accompanied by squealing, trumpeting, pirouetting, backing up and excreting.

Within the family herd, a sick or wounded member causes much agitation and apparent emotion. Those that falter may be supported between two or more adults, whilst fallen animals will be caressed, prodded and pushed in attempts to raise them.

Jumbo talk

Being such social animals, elephants have much to say to each other. This they do using more than 30 different infrasonic rumbles. Most are of very low frequency, in the 14-35 hertz (cycles per second) ranges, but one study of forest elephants found them capable of frequencies down to 5 hertz. (It’s generally accepted that humans can hear down to about 16 hertz).

Such low-pitched transmissions are amplified through the trunk and, running at about 103 decibels, can travel up to 8km when relatively unaffected by trees and other obstacles. These long sound waves are below the limits of human perception unless played back at four times their original speed. The throaty rumbles we can hear are used for closer contact and greetings, for which each individual has his or her own identifying signature sounds.

Infrasonic rumbles, the majority of which are made by the females, especially mothers, are also used to co-ordinate the group’s movement to advertise sexual readiness and to warn of danger. It is suspected that elephants can detect distress over long distances. It has been suggested, for example, that a sudden upsurge in aggressiveness amongst elephants in Savuti, Botswana, was the result of messages received a few hours after culling began in Zimbabwe’s Hwange NP, about 200km away.

The distant rumble of thunderstorms, inaudible to humans, is also infrasonic. Elephants detecting these sounds move towards the storm hours ahead of its occurrence – an action noted and copied by other animals parched with thirst.

Elephants also roar through their trunks, to produce classical trumpeting or screaming when alarmed, angered or showing aggression. A charge may, or may not, begin with a warning comprising head shaking, often accompanied by audible trunk and ear snapping and a harsh, shrill and absolutely terrifying scream. If this warning is ignored, the beast bursts forth, eyes red and straining to focus on its target, ears spread intimidatingly wide, head lowered and trunk circled under. The tail is raised tensely in anger. Despite Hollywood films, elephant charges are vocally mute.

However, when confronted, elephants often move away, sometimes even after issuing a warning. But when danger to youngsters is perceived, the herd will laager, drawing up an impenetrable shield of adults in a circle around the calves. They face out, ears spread, heads held high and swinging from side to side, trumpeting and screaming. Alternatively, the herd may choose to run off in a tight bunch, the youngsters shielded by the adults.

When the mighty have fallen

Like birth, death has a profound effect on the family unit. Elephants keep vigil over dying and dead relatives, display much emotion at death and are markedly affected afterwards.

When the deceased leaves behind a small calf, further tragedy ensues. Babies under two don’t survive without their mother’s milk. For older orphans there is hope, as other adults usually take care of the stricken youngster. In a few cases, another adult has even adopted an orphan. The most devastating experience, however, is the loss of the matriarch, for it often results in the splitting of the family.

Elephants exhibit a strong fascination with the bones of their dead, but completely ignore those of other animals. They conduct a thorough investigation: moving, lifting, rearranging and sometimes even carrying around the remains. Some researchers speculate that, with their incredible olfactory powers, elephants can identify the bones of departed relatives from their particular scent. That it is often the dead animal’s siblings that linger the longest perhaps supports such a theory.

The dead are sometimes ‘buried’, trunkfuls of dirt being tossed over the body and branches laid to cover it. Human victims of elephant attacks have occasionally been treated in a similar manner.

Physically, humans are worlds apart from elephants, but perhaps their emotions explain why we identify with them so readily.

Learn more about elephants in our themed wildlife issue, available here.

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