The Asian or Asiatic elephant (Elephas maximus) is the
only living species of the genus elepas and is distributed in South Anastasia from India in the west to Borneo in the
east. Three subspecies are recognized from Sri lanka
from the island of Sumatra. Asian elephants are the largest living land animals
in Asia.Since 1986, E. maxims has been listed as the population has
declined by at least 50% over the last three generations, estimated to be 60–75
years. The species is primarily threatened by habitat loss, degradation and
fragmentation. In 2003, the wild population was estimated at between 41,410 and
52,345 individuals. Female captive elephants have lived beyond 60 years when kept
in semi natural situations, such as forest camps.While subspecies taxonomy of Elephas maximus has varied among authors, the most recent treatment (Shoshani and Eisenberg 1982) recognizes three subspecies: E. m. indicus on the Asian mainland, E. m. maximus on Sri Lanka, and E. m. Sumatrans on the Indonesian island of Sumatra. Borneo's elephants have traditionally been included in E. m. indicus (Shoshani and Eisenberg 1982) or E. m. sumatranus (Medway 1977; but see Fernando et al. 2003 and Cranbrook et al.
2008 for discussion of whether the elephants of Borneo are indigenous
to the island). These subspecies designations were based primarily on
body size and minor differences in coloration, plus the fact that E. m. sumatranus
has relatively larger ears and an extra pair of ribs (Shoshani and
Eisenberg 1982). The Sri Lankan subspecies designation is weakly
supported by analysis of allozyme loci (Nozawa and Shotake 1990), but
not by analysis of mitochondrial DNA (mtDNA) sequences (Hartl et al. 1996, Fernando et al. 2000, Fleischer et al. 2001). However, current patterns of mtDNA variation suggest that the Sumatran subspecies is monophyletic (Fleischer et al.
2001), and consequently this taxon could be defined as an
evolutionarily significant unit (ESU). This suggests that Sumatran
elephants should be managed separately from other Asian elephants in
captivity, and is also an argument for according particularly high
priority to the conservation of Sumatran elephants in the wild. The
status of evolutionarily significant unit has also been suggested for
the Borne an elephants (Fernando et al. 2003). Two other proposed subspecies E. m. assures and E. m. rubrics are extinct. A definitive sub specific classification awaits a detailed range-wide morphometric and genetic study.
