Distribution

• Historic range:
  • Tigris and Euphrates eastward through Persia
  • Indian subcontinent,
  • South and Southeast Asia
  • China up to the Yangtze-Kiang
• Current populations:
  • Indian subcontinent (India, Nepal, Bhutan, Bangladesh)
  • Continental Southeast Asia (China, Myanmar, Thailand, Kampuchea, Laos, Vietnam, Malaysia)
  • Asian islands (Andaman Islands, Sri Lanka, Sumatra, Borneo)
• Presently occupy only 15% of historic range
• India has 60% of remaining wild populations
• E. m. borneensis' occupied Borneo in prehistoric times - not imported from India
• Updated range map available from IUCN (2008).

Present distribution and population sizes

Habitat

• Primary habitat types
  • Tropical and subtropical moist broadleaf forests
  • Tropical and subtropical dry broadleaf forests
• Move through vegetation zones seasonally; often found along rivers in dry months
• In Southern India: hilly dry scrub through deciduous forest to wet evergreen forest
• Northeastern India and Burma: swampy grasslands on river floodplains; moist deciduous forest on Himalayan slopes
• Sri Lanka: mainly dry deciduous woodland, scrub, grassland, and marshes; small population in rainforest
• India's Andaman Islands: swim across sea between various islands
• Prefer transitional zones between two ecological communities (forests and grasslands)
• Require more access to shade than African elephants
• Inhabit more low visibility habitats compared to African elephants 

• 2000-5500 kg. (4,500-12,000 lbs.)
• Largest living land mammal (several whales are larger)

• 5.5-6.5 m. (18-21 ft.)

• 1.2-1.5 m. (4-5 ft.)
• Tail of Elephas m. boreensis longer than other subspecies - almost touches the ground

• Female: 2.24 m. (8 ft.)
• Male: 3.2 m. (10 ft.)
• A bull displayed at the Smithsonian's National Museum of Natural History measured 4 m (13 ft.) at the shoulder
• Shoulder height = forefoot circumference X 2

General

• All elephants have versatile proboscis or trunk, columnar legs, thick skin (pachydermous), and sparse patches of hair
• Smaller than African elephants
• Convex or level back vs more concave in African elephant
• Highest point is at head vs at shoulder in African elephant
• Sri Lankan subspecies is the largest

Skin

• Skin has several textures depending according to location on body
  • Bumpy skin on most of body
  • Smooth skin on ears, lips, eyelids, genitalia
  • Rough texture isn't found in skin of other mammals
• Generally smoother than the African Elephant’s
• Thick skin - protects against insect bites and weather
• Usually gray. May have white or pink blotches on ears, trunk, head or neck
• Sumatran elephants lightest in color and have least depigmentation (loss of color).
• Sri Lankan elephants darkest and have distinct depigmentation
• Frequently bathe with water, mud or soil to control body temperature

Hair and Nails

• Number of nails don't match number of digits
  • Asian elephants: usually 5 nails on forefeet and 4 to 5 nails on hind feet.
  • African species: typically 4 to 5 nails on forefeet and 3, 4, or 5 on hind feet
• Infants have "downy" reddish or black hair later replaced by short soft bristles
• Long soft hairs surround ear openings and lower lip
• Short tactile hairs on trunk
• Asians generally harrier than African elephants

Skeleton

• Equals about 15% body weight
• Skull weight equals about 52 kg. (115 lbs.); extensive honeycomb-like spaces reduce skull's weight
• Very short neck brings head close to the center of gravity. Cannot turn head side to side
• Sumatran elephant has 20 sets of ribs, others subspecies have 19 (last 4 are floating)
  • African Elephant has 21 sets of ribs
• Side-to-side movement of limbs from the center of the body restricted.
  • Increases stability and prevents falls, which can be fatal.
• Feet rest on pads of shock-absorbent, elastic connective tissue, which help support weight
• 34 tail vertebrae
  • 33 in African elephants
    

Teeth

• Chewing surfaces of teeth are closed, compressed loops; those of African Elephant are diamond-shaped
• Teeth have a high crown with rasp-like surface, which allows them to chew high fiber materials.
• 26 teeth over lifetime: 2 upper incisors (tusks), 12 deciduous premolars, 12 molars. No canines.
• Six sets of 4 molars molars during lifetime
  • Average replacement ages are at 1.5 to 2 years, 6 years, 8 to 10 years, 20 to 25 years and at 50 to 6 0 years.
  • The final set is usually lost between 60 and 70 years of age. (Eltringham,1991, p.40).
  • Because the teeth change in size and shape throughout life, age of an individual can be estimated
• New molars do not erupt vertically as in most mammals, but grow in from behind, pushing the old worn-out teeth forward and out.
• A single molar can weigh over 5 kg (11 lbs).

Tusks

• Function: dig for water, salt or rocks, debark trees, serve as weapons, protection or rests for the trunk, move branches
• Favors either left or right tusk . One tusk usually shows more wear than the other.
• Elephant incisors develop into tushes and tusks
  • Tushes barely extend past the mouth; replaced by permanent tusks
  • Permanent tusks in place by 6 to 12 mos; grow about 17 cm (7 in. )/yr. depending on nutrition
  • Large tusks up to 1.8 m (5.9 ft); slimmer and straighter than African's
    • Longest tusk on record: 3 meters (119 in.).
    • Heaviest weighed 39 kg. (86 lbs)
• Females are tuskless, or have tushes
• Proportion of tuskless males varies widely (0 to 100%). They are called "makhnas."
  • Both male and female African elephants usually have tusks
• Tusk microstructure seen in cross section ("Schreger lines") allow identification of various elephant taxa

Trunk

• Technical term is “proboscis," meaning "before the mouth" (Greek)
• Tool for lifting, smelling, spraying dust, grass, and water on body
• Used to transfer water to mouth, not used like a drinking straw
• Also used for sound production, courtship, calf assurance during nursing, behavioral signals and displays
• More "rings" (annulations) than in African Elephant's and perhaps is more extendable
• Formed by a fusion of the nose and upper lip
  • One prehensile “finger” at tip of trunk (mammoths had one also); African elephant has two "fingers"
    • Three types of tactile receptors at tip; most sensitive part of the trunk
• Contains as many as 150,000 muscle units
• Muscle masses aligned in radial, longitudinal, and oblique layers for extraordinary flexibility
  • Tongues of vertebrates, arms of octopus and tentacles of squid have similar flexibility
• 70% of air inhaled is through the trunk, the rest comes through the mouth.
• Uses trunk to transfer water to mouth, not used for drinking;can hold up to 5 liters (1.3 gal) water
• Uses trunk to transfer chemical pheromones to receptors in the mouth
• Trunk tip's contain nerve endings with heightened sensitivity to vibrations
  • When placing trunk tip on ground, can detect vibrations of running animals

Ears

• Smaller than the African elephant's.
• E.m. borneensis has larger outer ear (pinna) than other subspecies
• Thermo regulation - positive correlation between the number of times an elephant flaps its ears and air temperature.
• Cochlea's curved structure may facilitate sensitivity to low frequencies.
  • Can hear approximately 8Hz. – 12 kHz
• For comparison: humans hear up to 19kHz and dogs to 44 kHz
• Represent best sensitivity of all mammals so far tested (Langbauer 2000)
• May be able to detect seismic vibrations from thunderstorms, animal hooves through feet

Glands

• Two pectoral mammary glands produce milk that is 83.82% water, 11.82% albuminoids and sugar, 3.89% fat and 0.47% ash or mineral matter.
• Cheek (temporal) glands located midway between eyes and ears. Drain during times of excitement such as fighting, mating or in musth (once or twice a year)
  • Produce pheromones that stimulate other elephants' behavior
  • Present in both males and females; much more active in males
• Tear ducts are vestigial. Herderian glands lubricate the eyes.

Internal Organs

• Weight of heart 19 kg (42 lbs); about 0.5 % of body weight. Unique shape like the African Elephant with bifed apex and paired venae cavae
• Heart rate 28 beats per minute standing; 35 lying down
• Rate of respiration 4-12 per minute
• Brain weight 5.5 kg (12 lbs). Large temporal lobes indicate heightened memory capabilities. Larger than humans', relative to body size
• Absence of gall bladder (have low-fat diet)
• Pancreas does not come in contact with spleen, unlike most animals.
• Testes located near kidneys inside abdomen; heat-sensitive sperm ok because of elephant's lower body temperature
• Lungs attached to diaphragm; typically breathe using diaphragm rather than expansion of rib cage

Eyesight

• Eye is small in relation to body size
• Ability to see color - probably similar to humans who are color blind
• Total visual field is a sweep of 313° out of 360° with a 47° blind spot (compared to 357° visual field for a horse)
• No true tear ducts
• Good in dull light, considerably reduced in bright light

Sexual Dimorphism

• Males have large trunk bases, bulges below and in front of eyes, and swelling above the eyes. Females have narrower trunk bases and lack prominent bulge above eyes
• Male back is more convex and curves more gradually into hindquarters; female's is straighter and "boxier" with vertical hindquarters.
• Males considerably larger than females of same ages.

Other Physical Characteristics

• Folds in brain resemble that of humans and porpoises
• Highly sensitive Jacobson's organ on roof of mouth used for detecting sex pheromones

Activity Cycle

• In a study of Asian Elephants at Lahugala Tank, males were recorded as having the following activity cycle:
  91.1% = Feeding
  5.4% = Walking
  1.4% = Resting
  1.8% = Bathing
  0.1% = Drinking
  0.2% = All other activities

• Another study at Lahagula Tank records the following activity cycle of solitary males:
  93.5% = Feeding
  1.9% = Walking
  0.3% = Contact promoting
  3.3% = Play/Aggression
  1.0% = All other activities
• Female elephant herds spend 70-90% of time feeding.
• Male activity shows one peak at around 8 am and another between 4-5 pm. Female herds peak around 10 am and then later between 3:30 and 6 pm.
• In a study at Ceylon's Wilpattu National Park for individuals described as secretive and shy
  • Feeding is intermittent during 24 hour period
  • Drinking is typically early evening and just before daybreak
  • Long distance travel usually accomplished at night

Territory Size

• No evidence of territoriality
• Home range size usually small, similar to African Elephants (approx. 14-52 sq.km)
  • Shifts locale with wet/dry season
  • Availability of resources (water, food, mates) and human presence all influence home range size
• Female groups may overlap and coordinate migrations

Social Groups

• Highly social animals with complex behavior
• A matriarch, typically the eldest female, heads a related group of females.
  • Study of female groups's genetics at Ruhuna National Park in Sri Lanka show all individuals related to a single female
• Herds consist of about 8-12 individuals, but sizes can vary. (African Elephant groups: 10 to 20 individuals)
• Life centers around the calves in both African and Asian elephant societies.
• Females share equally in the care of the young.
• Teenage males leave natal herd & often form bachelor groups 
• Adult male typically described as solitary; no close bonds with other independent males; spend time in families only when following females in estrus
  • New studies show the males form loose associations

Hierarchy

• Males in musth are dominant to nonmusth males
• Teenage Asian elephants (15-20 years) go through a juvenile (moda) musth in which they secrete a sweet odor
  • Scent signals subordinate status, eliminating unnecessary conflict with older, dominant males.

Aggression

• Bulls in musth once or twice a year may display aggressive behavior
• Having a male in musth decreases aggressive behavior of other males
• Aggressive behaviors include: spreading ears; raising head with jaw "tucked in", mock charging, abrupt head shake which makes ears flap, throwing objects in direction of opponent
• Elephant charge: up to 40 km/hr (25mph)

Play

• Male calves are more likely to leave mothers to play; engage in head sparring, mounting, charging, shoving, and chasing
• Female calves play chasing and running games, throw sticks, and may “attack” imaginary enemies
• Both sexes play rough and tumble games, clamber onto each other

Communication

• Large repertoire of vocalizations, including:
  
  • Low frequency, long distance calls to maintain contact between roving individuals or groups
  • Close range, high pitched calls indicate mood
  • Loud trumpeting indicates alarm, surprise
  • Low snorts signal changes in immediate environment, alerting herd

• Family members often touch while standing; may rub with a foot or slap with the trunk
• Trunks are used in greeting: A lower-ranking animal will insert its trunk tip into the other’s mouth
• Trunk may be held out to an approaching elephant as a greeting
• Trunk is also used in caressing, twining, wrestling, and checking reproductive status
• Mothers may guide their calf by gripping its tail

• Signal for hormonal state:
  • Bull's musth walk - head erect, ears wide, ear waves of one ear, a low pulsing growl
  • Trunk curling and uncurling
  • Urine dribble
  • Cow's estrous walk - looking back over shoulder as walk away
• Signals for apprehension/submission
  • Jaw out, touching one's own temporal gland or face
  • Trunk twitching back and forth
  • Swaying side to side
  • Backing into side of more dominant animal

• Rely heavily on long lasting chemical cues, which travel over short or long distances
• Lift trunks to detect wind borne scents for first clues to sources of danger
• Survival depends on reading scents of landscapes, pathways, mineral and salt sources, waterholes
• Even after long separations, chemical cues help reestablish kin and friendship bonds
  • Sniff breath, mouths, temporal glands, genitals, urine and dung to determine emotional and physiological states of others
    • Urine alone contains several thousand chemical compounds packed with messages
  • Sex pheromones allow determination of fitness and location of opposite sex

• Information from environment via low frequency ground vibrations may be first detected by elephant's feet and trunk tip
• Distant thunderstorms, footsteps of running animals, vocalizations, that travel through ground

Locomotion

• Move with one basic gait, known as the rack or pace (three feet are on the ground most of the time)
  ; one foot always on ground
• Normal walking speed 2.5-3.7 mph (4-6 km/hr). Charging speed can reach 15.2 mph (6.8 meters/sec) (Hutchinson 2006)
• Move very slowly while feeding, or walk quickly. Juveniles may run when playing, but adults only run in flight or attack.
• Swim readily at rate of 1.3 mph (2 km/hr). Can stay afloat for up to 6 hours and cover distances of 30 miles (48 km) at a stretch
• Can not jump; even a shallow ditch poses a barrier
• Can not trot, canter, or gallop

Tool Use

• May use branches and plant fronds to swat flies, dislodge parasites, scratch an itch
• Known to drop boulders on fences to destroy them or to cut off electricity

Interspecies Interaction

• Do not appear frightened by other animals; usually ignore them
• Confrontations with Indian rhinoceros probably very rare in wild, but have occurred with domestic elephants that have been ridden into rhino's territory
• Mutualistic relationship with some species of birds, such as egrets and piapiac.
  • Birds use elephants as a vantage point to spot prey; pick off ticks or lice attached to the elephant.
• Host several parasites, including louse, warble flies, mosquitoes and leeches
• Prodigious amounts of dung disperses many seeds and helps enrich soils
  • Dung beetles and termites carry dung underground
• Like the African Elephant, function in role of ecosystem "engineer" and as a keystone species
  • Maintain trails and open access to water for other species
  • Create microhabitats by shredding trees for small vertebrate species such as lizards
  • Uproot small trees (which would invade open grassland areas, shifting habitat to new forests)
    • Enhances habitat for other grazing animals and their predators