Elephant - Physical Characteristics
Description of physical Structure of Asian Elephant
- 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.
- All elephants have versatile proboscis or trunk, columnar legs, thick skin (pachy-dermous), 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 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.
- 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.
- 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.
- 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.
- 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 flex-ibility
- 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
- Trunk tip's contain nerve endings with heightened sensitivity to vibrations
- When placing trunk tip on ground, can detect vibrations of running animals.
- 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.
- 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
- Present in both males and females; much more active in males
- Tear ducts are vestigial. Herderian glands lubricate the eyes.
- 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.’
- 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