Asian Elephant (Elephas maximus) Fact Sheet: Physical Characteristics

*Largest living land mammal (several whales are larger)

**Tail of E. m. boreensis longer than other subspecies - almost touches the ground

***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

• Several textures depending according to location on body
  • Bumpy skin on most of body
  • Smooth skin on ears, lips, eyelids, and 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
• May be able to detect seismic vibrations from thunderstorms, animal hooves through feet

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
• Asian elephants generally more hairy 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 pairs 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 60 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 (118 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 contains 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
• Thermoregulation - 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 19 kHz and dogs to 44 kHz
  • Represent best sensitivity of all mammals so far tested (Langbauer 2000)

Glands

• Two 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
    • Highly sensitive Jacobson's organ on roof of mouth used for detecting sex pheromones
  • 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
• Gall bladder absent (have low-fat diet)
• Pancreas does not come in contact with spleen, unlike most animals.
• Testes located near kidneys inside abdomen; heat-sensitive sperm survive 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 some color
• 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

• 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

• Folds in brain resemble that of humans and porpoises

Close-up of an Asian elephant's head.

Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved.

Asian Elephant (left) has smaller ears than African Elephant (right).

Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved.

Texture of an Asian elephant's skin.

Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved.

An Asian elephant's sturdy legs and feet support its large body.

Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved.

Alter (2004)
Fowler & Makata (2006)
Hutchinson et al (2006)
Manoussaki el al (2007)
Mariappa (1986)
Shosani (1992)
Shoshani & Eisenberg (1982)
Sukumar (1989)
Yokoyama et al (2005)