African forest elephant
The African forest elephant is an elephant species native to humid tropical forests in West Africa and the Congo Basin. It was first described in 1900. With an average shoulder height of, it is the smallest of the three living elephants. Both sexes have straight, down-pointing tusks, which begin to grow at the age of 1–3 years.
The African forest elephant lives in highly sociable family groups of up to 20 individuals comprising adult cows, their daughters and sons. When young bulls reach sexual maturity, they separate from the family group and form loose bachelor groups for a short time, but usually stay alone. Adult bulls associate with family groups only during the mating season.
The African forest elephant forages on leaves, seeds, fruit, and tree bark of at least 96 plant species. Since it disseminates partly digested seeds for at least through its droppings, it contributes significantly to maintaining the diversity and structure of the Guinean Forests of West Africa and the Congolese rainforests.
During the 20th century, overhunting caused a sharp decline of the African forest elephant population, and by 2013 it was estimated that fewer than 30,000 individuals remained. It is threatened by habitat loss, fragmentation, and poaching. The conservation status of populations varies across range countries. Since 2021, it has been listed as Critically Endangered on the IUCN Red List.
Taxonomy
Elephas ''cyclotis'' was the scientific name proposed by Paul Matschie in 1900 who described the skulls of a female and a male specimen collected by the Sanaga River in southern Cameroon.Phylogeny and evolution
The African forest elephant was long considered to be a subspecies of the African elephant, together with the African bush elephant. Morphological and DNA analysis showed that they are two distinct species.The taxonomic status of the African pygmy elephant was uncertain for a long time. Phylogenetic analysis of the mitochondrial genome of nine specimens from museum collections indicates that it is an African forest elephant whose diminutive size or early maturity is due to environmental conditions.
File:Palaeoloxodon phylogeny.svg|left|thumb|Phylogeny showing the relationship between living and extinct elephantids including the hybridization between Palaeoloxodon, represented by the straight-tusked elephant and African forest elephants|250x250px
Phylogenetic analysis of nuclear DNA of African bush and forest elephants, Asian elephants, woolly mammoths and American mastodons revealed that the African forest elephant and African bush elephant are two distinct species that genetically diverged at least 1.9 million years ago. They are therefore considered distinct species. Despite evidence of hybridization between the two species where their ranges overlap, there appears to have been little gene flow between the two species since their initial divergence.
DNA from the extinct European straight-tusked elephant indicates that members of the extinct elephant genus Palaeoloxodon interbred with African forest elephants, with over 1/3 of the nuclear genome as well as the mitochondrial genome of the straight-tusked elephant deriving from that of African forest elephants, with the genomic contribution more closely related to modern West African populations of the forest elephant than to other populations. Palaeoloxodon carried multiple separate mitochondrial lineages derived from forest elephants which were carried among both European straight-tusked elephant and Chinese populations of Palaeoloxodon, indicating this ancestry was widespread in Eurasian Palaeoloxodon populations.
Description
The African forest elephant is considerably smaller than the African bush elephant, though the size of the species has been subject to contradictory estimates. A 2000 study suggested that bulls of the species reach a shoulder height of, and weighed, while cows were about tall at the shoulder and. However, a 2003 study of forest elephants at a reserve in Gabon did not find any elephants taller than. A 2015 study alternately suggested that fully grown African forest elephant males in optimal condition were only on average tall and in weight, with the largest individuals no bigger than tall and in weight.The African forest elephant has grey skin, which looks yellow to reddish after wallowing. It is sparsely covered with black coarse hair, which is long around the tip of the tail. The length of the tail varies between individuals from half the height of the rump to almost touching ground. It has five toenails on the fore foot and four on the hind foot. Its back is nearly straight. Its oval-shaped ears have small elliptical-shaped tips, and the tip of the trunk has two finger-like processes.
The African forest elephant's tusks are straight and point downwards, and are present in both males and females. The African forest elephant has pink tusks, which are thinner and harder than the tusks of the African bush elephant. The length and diameter vary between individuals. Tusks of bulls grow throughout life, tusks of cows cease growing when they are sexually mature. The tusks are used to push through the dense undergrowth of their habitat. The largest tusk recorded for the species is long and in weight. A larger tusk measuring long and weighing has been recorded, but this may belong to a forest-bush elephant hybrid. The average tusk size is uncertain due to measurements historically being lumped in with those of African bush elephants, but based on the sizes of the largest known tusks may be in the region of and.
Distribution and habitat
Populations of the African forest elephant in Central Africa range in large contiguous rainforest tracts from Cameroon to the Democratic Republic of the Congo, with the largest stable population in Gabon, where suitable habitat covers 90% of the country.They are also distributed in the evergreen moist deciduous Upper Guinean forests in Ivory Coast and Ghana, in West Africa.
A group of about 10-25 African forest elephants has been sighted on the escarpment to the east of Luanda in the Kambondo forest in 2015.
Nonetheless, it was estimated that the population of African forest elephants in Central Africa had declined by around 86% due to poaching and loss of habitat. In places such as Cameroon, Democratic Republic of the Congo, Republic of the Congo and the Central African Republic, many areas of appropriate forest habitat have been reduced after years of warfare and human conflict. As of 2021, an estimated 95,000 forest elephants lived in Gabon. Prior to this the population had been estimated at 50,000 to 60,000 individuals.
Behaviour and ecology
The African forest elephant lives in family groups. Groups observed in the rain forest of Gabon's Lopé National Park between 1984 and 1991 comprised between three and eight individuals. Groups of up to 20 individuals were observed in the Dzanga-Sangha Complex of Protected Areas, comprising adult cows, their daughters and subadult sons. Family members look after calves together, called allomothering. Once young bulls reach sexual maturity, they separate from the family group and form loose bachelor groups for a few days, but usually stay alone. Adult bulls associate with family groups only during the mating season. Family groups travel about per day and move in a home range of up to.Their seasonal movement is related to the availability of ripe fruits in Primary Rainforests.
They use a complex network of permanent trails that pass through stands of fruit trees and connect forest clearings with mineral licks. These trails are reused by humans and other animals.
In Odzala-Kokoua National Park, groups were observed to frequently meet at forest clearings indicating a fission–fusion society. They stayed longer when other groups were also present. Smaller groups joined large groups, and bulls joined family units.
Diet
The African forest elephant is an herbivore. Elephants observed in Lopé National Park fed mostly tree bark and leaves, and at least 72 different fruits.To supplement their diet with minerals, they congregate at mineral-rich waterholes and mineral licks.
Elephant dung piles collected in Kahuzi-Biéga National Park contained seeds and fruit remains of Omphalocarpum mortehanii, junglesop, Antrocaryon nannanii, Klainedoxa gabonensis, Treculia africana, Tetrapleura tetraptera, Uapaca guineensis, Autranella congolensis, Gambeya africana and G. lacourtiana, Mammea africana, Cissus dinklagei, and Grewia midlbrandii. Dung piles collected in a lowland rain forest in the northern Republic of Congo contained seeds of at least 96 plant species, with a minimum of 30 intact seeds and up to 1102 large seeds of more than in a single pile. Based on the analysis of 855 dung piles, it has been estimated that African forest elephants disperse a daily mean of 346 large seeds per of at least 73 tree species; they transport about a third of the large seeds for more than.
Seeds passed by elephant gut germinate faster. The African forest elephant is one of the most effective seed disperser in the tropics and has been referred to as the "megagardener of the forest" due to its significant role in maintaining plant diversity. In the Cuvette Centrale, 14 of 18 megafaunal tree species depend on seed dissemination by African forest elephants, including wild mango, Parinari excelsa and Tridesmostemon omphalocarpoides. These 14 species are not able to survive without elephants.
African forest elephants provide ecological services that maintain the composition and structure of Central African forests.
Communication
Vocalization is a trait found among L. cyclotis with studies emphasizing significance in acoustic structure and their social dynamics. Vocalization patterns can be classified into three main types: single rumble, single broadband, and combinatorial. Rumbles are tonal, low-frequency calls, while broadband are calls that lack clear harmonic structures, resembling barks and roars. The utilization of rumbles and broadband calls in combinatorial calls may involve distinct acoustic elements, forming multi-element calls, which combine meaningless elements to generate context-specific meaningful calls. The African forest elephant also exhibits a more balanced distribution of combinatorial call types compared to other elephant species. Despite having a simpler social structure, L. cyclotis can display a comparable repertoire of rumble-roar call combinations than L. africana. Communication patterns vary across age and sex, with adult males typically producing more combinatorial calls than adult females. Additionally, certain events may provoke a behavioral change, as evidenced by lowered levels of vocalizations in response to gunfire sounds related to poaching.For these mammals, hearing and smell are the most important senses they possess because they do not have good eyesight. They can recognize and hear vibrations through the ground and can detect food sources with their sense of smell. Elephants are also an arrhythmic species, meaning they have the ability to see just as well in dim light as they can in the daylight. They are capable of doing so because the retina in their eyes adjusts nearly as quickly as light does.