Genus-Animalia: Loxodonta

African elephants (Loxodonta) are a genus comprising two living elephant species, the African bush elephant (L. africana) and the smaller African forest elephant (L. cyclotis). Both are social herbivores with grey skin, but differ in the size and color of their tusks and in the shape and size of their ears and skulls.

Both species are considered at heavy risk of extinction on the IUCN Red List; as of 2021, the bush elephant is considered endangered and the forest elephant is considered critically endangered. They are threatened by habitat loss and fragmentation, and poaching for the illegal ivory trade is a threat in several range countries as well.

Loxodonta is one of two extant genera of the family Elephantidae. The name refers to the lozenge-shaped enamel of their molar teeth. Fossil remains of Loxodonta species have been excavated in Africa, dating to the Middle Pliocene.

Taxonomy

The first scientific description of the African elephant was written in 1797 by Johann Friedrich Blumenbach, who proposed the scientific name Elephas africanus. Loxodonte was proposed as a generic name for the African elephant by Frédéric Cuvier in 1825. This name refers to the lozenge-shaped enamel of the molar teeth, which differs significantly from the rounded shape of the Asian elephant's molar enamel. An anonymous author used the Latinized spelling Loxodonta in 1827. Anonymous was recognized as authority by the International Code of Zoological Nomenclature in 1999.

Elephas (Loxodonta) cyclotis was proposed by Paul Matschie in 1900, who described three African elephant zoological specimens from Cameroon whose skulls differed in shape from elephant skulls collected elsewhere in Africa. In 1936, Glover Morrill Allen considered this elephant to be a distinct species and called it 'forest elephant'; later authors considered it to be a subspecies. Morphological and genetic analyses provided evidence for species-level differences between the African bush elephant and the African forest elephant.

In 1907, Richard Lydekker proposed six African elephant subspecies based on the different sizes and shapes of their ears. They are all considered synonymous with the African bush elephant.

A third species, the West African elephant, has also been proposed but it needs confirmation. It is thought that this lineage has been isolated from the others for 2.4 million years.

Description

Skin, ears and trunk
African elephants have grey folded skin up to 30 mm (1.2 in) thick that is covered with sparse, bristled dark-brown to black hair. Short tactile hair grows on the trunk, which has two finger-like processes at the tip, whereas Asian elephants only have one. Their large ears help to reduce body heat; flapping them creates air currents and exposes the ears' inner sides where large blood vessels increase heat loss during hot weather. The trunk is a prehensile elongation of its upper lip and nose. This highly sensitive organ is innervated primarily by the trigeminal nerve, and thought to be manipulated by about 40,000–60,000 muscles. Because of this muscular structure, the trunk is so strong that elephants can use it for lifting about 3% of their own body weight. They use it for smelling, touching, feeding, drinking, dusting, producing sounds, loading, defending and attacking. Elephants sometimes swim underwater and use their trunks as snorkels.

Tusk and molars
Both male and female African elephants have tusks that grow from deciduous teeth called tushes, which are replaced by tusks when calves are about one year old. Tusks are composed of dentin, which forms small diamond-shaped structures in the tusk's center that become larger at its periphery. Tusks are primarily used to dig for roots and strip the bark from trees for food, for fighting each other during mating season, and for defending themselves against predators. The tusks weigh from 23 to 45 kg (51–99 lb) and can be from 1.5 to 2.4 m (5–8 ft) long. They are curved forward and continue to grow throughout the elephant's lifetime.

Elephants have four molars; each weighs about 5 kg (11 lb) and measures about 30 cm (12 in) long. As the front pair wears down and drops out in pieces, the back pair moves forward, and two new molars emerge in the back of the mouth. Elephants replace their teeth four to six times in their lifetimes. At around 40 to 60 years of age, the elephant loses the last of its molars and will likely die of starvation which is a common cause of death. African elephants have 24 teeth in total, six on each quadrant of the jaw. The enamel plates of the molars are fewer in number than in Asian elephants.

Size
The African bush elephant is the largest terrestrial animal. Cows are 2.2–2.6 m (7.2–8.5 ft) tall at the shoulder and weigh 2,160–3,232 kg (4,762–7,125 lb), while bulls are 3.2–4 m (10–13 ft) tall and weigh 4,700–6,048 kg (10,362–13,334 lb). Its back is concave-shaped, while the back of the African forest elephant is nearly straight. The largest recorded individual stood 3.96 meters (13.0 ft) at the shoulder, and is estimated to have weighed 10,400 kg (22,900 lb). The tallest recorded individual stood 4.21 m (13.8 ft) at the shoulder and weighed 8,000 kg (18,000 lb).

The African forest elephant is smaller with a weight of up 4,000 kg (8,800 lb) and a shoulder height of 1.8–2.4 m (5 ft 11 in – 7 ft 10 in) in females and 2.4–3 m (7 ft 10 in – 9 ft 10 in) in males. It is the third largest terrestrial animal.

Distribution and habitat

African elephants are distributed in Sub-Saharan Africa, where they inhabit Sahelian scrubland and arid regions, tropical rainforests, mopane and miombo woodlands. African forest elephant populations occur only in Central Africa.

Reference: Wikipedia