THE ASIAN ELEPHANT (ELEPHAS MAXIMUS)
Asian elephants are distributed discontinuosly across the Asian continent. Nowadays their range comprises India, Nepal, Buthan, Bangladesh, Myanmar, Thailand, China, Laos, Cambodia, Vietnam, Malaysia, Indonesia and Sri Lanka. 60% of the total population inhabits the Indian peninsula. Being primarly forest animals their habitat is mainly represented by dry tropical thorn forests, deciduous forests and tropical rain forests. The dense canopy that characterizes the Asian elephant habitat makes census operations hard to carry out. However, according to recent estimates the current elephant population counts between 34,470 and 52,720 individuals in the wild and an additional 16,000 elephants held in captivity, mainly in the range states.
DISTRIBUTION AND HABITAT
CONSERVATION STATUS AND THREATS
The Asian elephant is listed as Endangered by IUCN (International Iunion for Conservation of Nature) and appears on Appendix I of CITES (Convention on International Trade of Endangered Species of Wild Fauna and Flora) since it became effective in July 1 1975.
Asian elephants have disappeared from ca. 90% of their historical range. Nowadays, isolated populations can be found in 13 range states of South and Southeast Asia with an approximate total range area of 878,639 km² which is about the 10% of the 8,613,003 km² historical range. Habitat loss and other threats have led to the tragic decline of at least 50% of the overall population over the last three generation – 75 years-. The ever growing human population density in Asia, as well as Asian industrial and technological development reduced elephant habitat to isolated patches sorrounded by rubber, tea, crop plantations and human settlements. As a consequence, the past few decades have witnessed a severe exacerbation of the human/elephant conflict. In India ca. 200 people are killed by wild elephants every year and ca. 50 more in Sri Lanka only. This events may end up in the killing of the elephants involved and induce a high level of reluctance, if not open opposition of the local communties towards elephant conservation plans.
Poaching is also a serious threat to Asian elephants. It occurs as a consequence of the human-elephant conflict as well as for ivory trade or live elephant smuggling for touristic purposes. In addition to the direct loss of the elephants poached, selective removal of tuskers has severe implications for elephant populations, such as a female biased sex ratio, a reduction in genetic variation and a decline in fecundity. For instance, while the avarage incidence of tusked males is equal to 60% among Asian elephant populations, poaching for ivory trade in Sri Lanka reduced it to only a 7%.
Asian elephants are classified as Megaherbivores. Males are 250-300 cm in height and weigh between 3500 to 6000 kg. Females reach 200-240 cm in height on average and 2500/ 3000 kg.
Asian elephants are highly intelligent and social animals. Their social structure is multi-tiered. The mother-calf unit represents the basic unit. More basic units assemble a joint-family unit. Two to four family units that associate frequently are called the “kin” or bond group. A number of family units and bond groups that coordinate their movements within the same range area is named “clan”. Bond group size ranges from 5 to 20 individuals, while clans can contain up to 100 elephants. Herds are a matriarchy led by the oldest female and are composed by adult females, newborns, youngsters and sub-adults only. As soon as males reach sexual maturity, around 13-15 years, they leave their natal herd. They may end up wandering alone or in temporary “bull herds” with weak social bonds. On the contrary, females become sexually mature between 10 and 14 years. They cycle every 14-16 weeks and once they conceive they undergo a 20-21 month-long gestation. They give birth to one calf -90 to 100 cm in height and about 100 kg in weight- every 4 to 5 years on average since the lactation period lasts up to 3 years. Twin birth is rare but possible. Bull elephants attain a higher hierarchical status when they come into “musth”, usually once a year during the winter. Throughout the musth period, testosterone level in the blood increases making the bull more aggressive towards other individuals, with higher chances to mate successfully. Musth can be externally detected by the presence of a liquid secretion from the bull's temporal glands.
Elephant's life expectancy is about 60 years in the wild and 80 years in captivity.
DIFFERENCES BETWEEN ASIAN AND AFRICAN ELEPHANTS
Asian and African elephants are both part of the same taxonomical familia but they are so different that they belong to two distinct genus. Asian elephant's latin name is Elephas maximus, while the African elephant's latin name is Loxodonta africana.
One of the most evident differences is the size. Adult African elephants can be up to 4 m high and weigh 4000-7,500 kg, whereas the biggest Asian males reach no more than 3.5 m and 6000 kg in weight.
Also African elephant's ears are bigger than Asian elephant's. This difference is strictly related to the high temperature that characterizes the African elephant habitat. In fact, ears have a major role in thermoregulation since they are full of capillary vessels that improve heat dispersion.
The trunk is also different among the two species. It is a multipurpose organ made of about 150,000 muscles. It can be 2 m long and 140 kg heavy. Other than being an essential part of their fine olfactory system and the breathing organ, it is also used as a prehensile organ to grasp food and take dust bath or as a syphon to suck up water and release it into the mouth.
Lastly, the trunk is very important in social interactions as it is used in tactile communication for showing both aggressive or affectionate behaviour. While African elephants have two fingerlike growths at the end of their proboscides, Asian elephants have only one.
Toenails vary among the two species. Asian elephants have 5 nails on the front feet and 4 (rarely 5) on the hind feet. African elephants have 4 on the front feet and 3 on the hind feet.
The lamella profile along the top of the molar teeth of the two species is different with ridges on the African elephant's teeth being diamond-shaped , while in the Asian elephant they are more tightly compressed.