4 .Biology and behavior

Evolution






The earliest known ancestors of modern-day elephants evolved about 60 million years ago. The ancestor of the elephants from 37 million years ago was aquatic and had a similar lifestyle to a hippopotamus.

Social behavior






Elephants live in a structured social order. The social lives of male and female elephants are very different. The females spend their entire lives in tightly knit family groups made up of mothers, daughters, sisters, and aunts. These groups are led by the eldest female, or matriarch. Adult males, on the other hand, live mostly solitary lives.

The social circle of the female elephant does not end with the small family unit. In addition to encountering the local males that live on the fringes of one or more groups, the female's life also involves interaction with other families, clans, and subpopulations. Most immediate family groups range from five to fifteen adults, as well as a number of immature males and females. When a group gets too big, a few of the elder daughters will break off and form their own small group. They remain very aware of which local herds are relatives and which are not.

The life of the adult male is very different. As he gets older, he begins to spend more time at the edge of the herd, gradually going off on his own for hours or days at a time. Eventually, days become weeks, and somewhere around the age of fourteen, the mature male, or bull, sets out from his natal group for good. While males do live primarily solitary lives, they will occasionally form loose associations with other males. These groups are called bachelor herds. The males spend much more time than the females fighting for dominance with each other. Only the most dominant males will be permitted to breed with cycling females. The less dominant ones must wait their turn. It is usually the older bulls, forty to fifty years old, that do most of the breeding.

The dominance battles between males can look very fierce, but typically they inflict very little injury. Most of the bouts are in the form of aggressive displays and bluffs. Ordinarily, the smaller, younger, and less confident animal will back off before any real damage can be done. However, during the breeding season, the battles can get extremely aggressive, and the occasional elephant is injured. During this season, known as musth, a bull will fight with almost any other male it encounters, and it will spend most of its time hovering around the female herds, trying to find a receptive mate.

Mating behaviour






The mating season is short and females are only able to conceive for a few days each year. She will detach herself from the herd. The scent of the female (cow) elephant in heat (or estrus) attracts the male and she also uses audible signals to attract the male. As the female can usually outrun the male, she does not have to mate with every male that approaches her.

The male initiates the courtship and the female ignores him for several minutes. He then stops and starts again. Elephants display a range of affectionate interactions, such as nuzzling, trunk intertwining, and placing their trunks in each other's mouths.

In a rarely observed display of his affection, he may drape his trunk outside of his tusks during the ritual (image 1). The interactions may last for 20–30 minutes and do not necessarily result in the male mounting the female, though he may demonstrate arousal during the ritual .

The female elephant is not passive in the ritual and uses the same techniques as the male.

African as well as Asiatic males will engage in same-sex bonding and mounting. The encounters are analogous to heterosexual bouts, one male often extending his trunk along the other's back and pushing forward with his tusks to signify his intention to mount. Unlike heterosexual relations, which are always of a fleeting nature, those between males result in a "companionship", consisting of an older individual and one or two younger, attendant males. Same-sex relations are common and frequent in both sexes, with Asiatic elephants in captivity devoting roughly 46% of sexual encounters to same-sex activity.

Rogue elephant is a term for a lone, violently aggressive wild elephant. It is a calque of the Sinhala term hora aliya. Its introduction to English has been attributed by the Oxford English Dictionary to Sir James Emerson Tennent, but this usage may have been pre-dated by William Sirr.

Intelligence





With a mass just over 5 kg (11 lb), elephant brains are larger than those of any other land animal. A wide variety of behaviours associated with intelligence have been attributed to elephants, including those associated with grief, making music, art, altruism, allomothering, play, use of tools, compassion and self-awareness. Elephants may be on a par with other intelligent species, such as cetaceans and non-human primates. The largest areas in the elephant brain are those responsible for hearing, smell and movement coordination.

Senses





Elephants have well innervated trunks, and an exceptional sense of hearing and smell. The hearing receptors reside not only in ears, but also in trunks that are sensitive to vibrations, and most significantly feet, which have special receptors for low frequency sound and are exceptionally well innervated. Elephants communicate by sound over large distances of several kilometers partly through the ground, which is important for their social lives. Elephants are observed listening by putting trunks on the ground and carefully positioning their feet.

The eyesight of elephants is relatively poor.

Self-awareness





Mirror self recognition is a test of self awareness and cognition used in animal studies. A mirror was provided and visible marks were made on the elephant. The elephants investigated these marks, which were visible only via the mirror. The tests also included non-visible marks to rule out the possibility of their using other senses to detect these marks. This shows that elephants recognize the fact that the image in the mirror is their own self and such abilities are considered the basis for empathy, altruism and higher social interactions. This ability has also been demonstrated in humans, apes, Bottlenose dolphins, and magpies.

Communication





Elephants make a number of sounds when communicating. Elephant are famous for their trumpet calls which are made when the animal blows though its nostrils. Trumpeting is usually made during excitement. Its use varies from startlement to a cry of help to rage. Elephants also make rumbling growls when greeting each other. The growl becomes a bellow when the mouth is open and a bellow becomes a moan when prolonged. This can escalate with a roar when threatening another elephant or another animal.

Elephants can communicate over long distances by producing and receiving low-frequency sound (infrasound), a sub-sonic rumbling, which can travel in the air and through the ground much farther than higher frequencies. These calls range in frequency from 15–35 Hz and can be as loud as 117 dB, allowing communication for many kilometres, with a possible maximum range of around 10 km. This sound can be felt by the sensitive skin of an elephant's feet and trunk, which pick up the resonant vibrations much as the flat skin on the head of a drum. To listen attentively, every member of the herd will lift one foreleg from the ground, and face the source of the sound, or often lay its trunk on the ground. The lifting presumably increases the ground contact and sensitivity of the remaining legs. This ability is thought also to aid their navigation by use of external sources of infrasound. Discovery of this new aspect of elephant social communication and perception came with breakthroughs in audio technology, which can pick up frequencies outside the range of the human ear. Pioneering research in elephant infrasound communication was done by Katy Payne, of the Elephant Listening Project,[51] and is detailed in her book Silent Thunder. Though this research is still in its infancy, it is helping to solve many mysteries, such as how elephants can find distant potential mates, and how social groups are able to coordinate their movements over extensive range.

Diet







Elephants are herbivores, and spend up to 16 hours a day eating plants. Their diet is highly variable, both seasonally and across habitats and regions. Elephants are primarily browsers, feeding on the leaves, bark, and fruits of trees and shrubs, but they may also eat consderable grasses and herbs. As is true for other non-ruminant unglulates, elephants only digest approximately 40% of what they eat. They make up for their digestive system's lack of efficiency in volume. An adult elephant consumes 140–270 kg (300–600 lb) of food a day.