Posted on 14 June 2004
Questions answered on the sub-species status of two African Elephant species
WWF QUESTIONS AND ANSWERS:
TWO SPECIES OF AFRICAN ELEPHANT
1. Does recent research resolve once and for all whether there are two separate species of African elephant?
Not necessarily. Recent research work is based on an analysis of the morphological and genetic differences between the two forms of African elephant, previously classified as sub-species (Loxodonta africana africana
and L. africana cyclotis
). The research proposes that these are two species, the Bush (or Savanna) African elephant (Loxodonta africana
) and the Forest African elephant (Loxodonta cyclotis
). By the biological definition of a species, it is unable to inter-breed with other species and produce viable offspring that can go on to reproduce themselves. There is evidence that forest and savanna elephants do hybridise at the forest edge in certain parts of Africa, such as around the Democratic Republic of Congo (DRC)/ Rwanda/Uganda border. If evidence emerges that these animals are reproductively viable hybrids, the "species or sub-species" debate may re-open. However, for the time being, WWF - along with the IUCN/SSC African Elephant Specialist Group - continues to recognise the two forms of African elephant as sub-species.
2. What are the conservation implications if there are two species?
We would have to consider both species in conservation and management decision-making. This would be particularly important for those countries with both forest and savanna elephants (e.g. Côte d’Ivoire, Cameroon, DRC). These range states would need to monitor and protect both species to maintain elephant genetic diversity.
Conservation agencies like WWF are already targeting both sub-species for their conservation work. For example, the long-term goal of WWF’s African Elephant Programme is:
"Forest and savanna elephant populations in Africa conserved."
Therefore, whether the elephants are sub-species or species, WWF's approach will remain the same in order to conserve their genetic diversity
3. What are the morphological differences between the savanna and forest elephants of Africa? And the behavioural differences?
Morphological differences: Forest elephants are smaller (male shoulder height is 2.4-3.0m compared to 3.2-4.0 m in bush elephants; weight is 2,000-4,000 kg cf 4,000-7,000 kg), they have more oval-shaped ears and their tusks are straighter and downward pointing (the tusks of bush elephants curve outwards). There are also differences in the size and shape of the skull and skeleton.
Behavioural differences: habitat use (bush elephants are found in savannas and woodlands; forest elephants are found in dense forest); diet (the forest elephant is much more of a browser and frugivore i.e. it feeds more on leaves and fruit; the savanna elephant often grazes on grass) social organisation (forest elephants live in smaller social groups of 2 to 4 individuals compared with 4-14 in bush elephant herds; bull forest elephants tend to be solitary whereas the savanna bulls associate more with herds.) communication (forest elephants communicate with lower frequency calls – 5 hertz compared to 14-24 hertz in their savanna counterparts).
4. How many forest elephants exist and in what countries? And savanna elephants?
The overall continental elephant population is estimated at 400,000 - 660,000 (IUCN 2003). However, no detailed analysis has yet been done to determine how many are from each species. The main source of information on elephant numbers, the IUCN African Elephant Database, does not differentiate between the two forms. However, it is estimated that probably one quarter to one third of the total African population is made up of forest elephants.
It is difficult to get accurate information on forest elephant numbers - since they live in dense forest you cannot conduct aerial surveys as you can for the bush elephant ion savanna and woodland areas. Therefore, forest elephant numbers are usually estimated through "dung counts" – an analysis on the ground of the density and distribution of the faeces.
Forest elephants are found most commonly in countries with relatively large blocks of dense forest in central Africa (e.g. DRC, Cameroon, Central African Republic) and west Africa (e.g. Côte d’Ivoire, Liberia, Ghana). Bush elephants predominate in eastern and southern Africa, where the highest densities are found in Botswana, Tanzania, Zimbabwe, Kenya, Zambia and South Africa.
5. Why does it matter if they are separate species?
Research – we now need to consider the two forms separately when conducting any type of biological, ecological or behavioural research.
Conservation – whether they are separate sub-species or species, we need to ensure the genetic diversity of elephants is fully maintained and that viable populations of both forms survive. Conservation of both sub-species also has wider implications for the habitats they live in. Forest elephants are essential for the germination of many rain forest trees; the activities of bush elephants contribute to the maintenance of savanna and open woodland by reducing tree densities. Without elephants, therefore, many other plants and animals would not survive in the savanna, woodland and forest habitats of Africa.
23-8-01; revised 14-06-04