Elephants

Superorder: Afrotheria
Order: Proboscidea
Family: Elephantidae
Genera

  • Loxodonta (Greek for 'oblique-sided tooth)(aka African) 
    • African forest elephant (L. cyclotis)
    • African bush elephant (L. africana)
  • Elephas 
    • Asian elephant (E. maximus )


Elephants are the largest living land mammals. The classic Africa adult male elephant reach a height of 4 m  and weigh around 7,000 kg. 


African_Elephants_in_Sweetwater_National_Parks_Kenya

A herd of African elephants in Sweetwaters Tented Camp, Kenya. image: Jan Arkesteijn /wikimedia

Elephants are herbivorous and live up to 70 years in the wild. They communicate by touch, sight, smell and sound; elephants use infrasound, and seismic (ground vibrations) communication over long distances.

Elephants are distantly related to a clade (a group that all have a common ancestor) of animals called Afrotheria which include creatures such as tenrecs, aardvarks, hyraxes, and sea cows (dugongs, Manatees).

African Elephant (loxodonta africana). image: wikimedia

Distribution 

Elephants are scattered throughout sub-Saharan Africa, South Asia, and Southeast Asia. Elephantidae is the only surviving family of the order Proboscidea; other, now extinct, members of the order include deinotheres, gomphotheres, mammoths, and mastodons.

Distribution of African Elephants

Distribution of Asian Elephants


Basic description

All elephants have several distinctive features, the most notable of which is a long trunk or proboscis, used for many purposes, particularly breathing, lifting water, and grasping objects. 

Their incisors grow into tusks, which can serve as weapons and as tools for moving objects and digging. Elephants' large ear flaps help to control their body temperature.

 Their pillar-like legs can carry their great weight. African elephants have larger ears and concave backs while Asian elephants have smaller ears and convex or level backs.

Comparative morphology of head and forepart of the body of the Asian elephant (1) and the African elephant (2). image: wikipedia


Ears

Elephant ears have thick bases with thin tips. The ear flaps, or pinnae, contain numerous blood vessels called capillaries. Warm blood flows into the capillaries, helping to release excess body heat into the environment. This occurs when the pinnae are still, and the animal can enhance the effect by flapping them. 

Angry_elephant_ears

African elephant with ears spread in a threat or attentive position; note the visible blood vessels. image: Mister-E/wikipedia 

larger ears help in cooling

Larger ear surfaces contain more capillaries, and more heat can be released. Of all the elephants, African bush elephants live in the hottest climates, and have the largest ear flaps.  Elephants are capable of hearing at low frequencies and are most sensitive at 1 kHz


Trunk

The trunk, or proboscis, is the eventual fusion of the nose and upper lip. The trunk is elongated and specialised to become the elephant's most important and versatile appendage. It contains up to 150,000 separate muscle fascicles (bundles), with no bone and little fat.

Elephant trunks have multiple functions, including breathing, olfaction, touching, grasping, and sound production.

Asian_Elephant,_Royal_Chitwan_National_Park

Asian elephant drinking water with trunk. image: Barbara Piuma/wikipedia


The trunk's ability to make powerful twisting and coiling movements allows it to collect food, wrestle with other elephants,  and lift up to 350 kg .


Behaviours,  habitats and ecology

Elephants are herbivorous and can be found in different habitats including savannahs, forests, deserts, and marshes. They prefer to stay near water. They are considered to be keystone species due to their impact on their environments. 

Other animals tend to keep their distance from elephants while predators, such as lions, tigers, hyenas, and any wild dogs, usually target only young elephants (or "calves"). 

Females ("cows") tend to live in family groups, which can consist of one female with her calves or several related females with offspring. The groups are led by an individual known as the matriarch, often the oldest cow. 

African bush elephants go on seasonal migrations in search of food, water, minerals, and mates. At Chobe National Park, Botswana, herds travel 325 km to visit the river when the local waterholes dry up.

Elephant society

Elephants have a fission–fusion society in which multiple family groups come together to socialise. Males ("bulls") leave their family groups when they reach puberty and may live alone or with other males. Adult bulls mostly interact with family groups when looking for a mate and enter a state of increased testosterone and aggression known as musth, which helps them gain dominance and reproductive success. 

Elephants_at_Amboseli_national_park_against_Mount_Kilimanjaro

A family of African elephants: note the protected position of the calves in the middle of the group. image: Amoghavarsha JS amoghavarsha.com/wikipedia


Baby elephants

Calves are the centre of attention in their family groups and rely on their mothers for as long as three years. Gestation in elephants typically lasts around two years with interbirth intervals usually lasting four to five years. Births tend to take place during the wet season.  Calves are born 85 cm  tall and weigh around 120 kg .

Communication

They communicate by touch, sight, smell, and sound; elephants use infrasound, and seismic communication over long distances. 

Intelligence

Elephant intelligence has been compared with that of primates and cetaceans. They appear to have self-awareness and show empathy for dying or dead individuals of their kind.


Source adapted from: Elephant. (2017, June 15). In Wikipedia, The Free Encyclopedia. Retrieved 05:42, June 16, 2017 , from https://en.wikipedia.org/w/index.php?title=Elephant&oldid=785714549