When is an elephant a picky eater? A study of the African elephant finds that, despite its large size and fast-operating digestive system, this mammal does not eat just anything. This mega-herbivore selectively chooses species and parts of the woody plants that comprise its diet.
An article in the current issue of Journal of Mammalogy explored the dietary habits of the African elephant. Researchers investigated what plants this animal selected, what parts of a plant it consumed, and how its choices varied with seasonal changes.
Previous studies suggested that the larger the animal, the less selective it might be in its diet, due to lower nutrient requirements per unit of body mass. Accordingly, a large animal would be more capable than a smaller one of digesting high-fibre content and potentially toxic chemical contents of some plants. Thus the African elephant, the largest extant herbivore, should be willing and able to consume a broad variety of plant species.
This study looked at the dietary patterns of more than 80,000 elephants in the Chobe National Park of Botswana. While its size and hindgut digestion do enable the African elephant to exploit a large assortment of plants, it seems to occupy a rather distinct niche from other animals in its actual choices.
During the wet season, elephants ate only 30 per cent of the woody species available for consumption. In the hot, dry season, this increased to 50 per cent. While the elephant might eat shoots and leaves during the wet season, it prefers stem, bark, and roots, making up 50 per cent of its diet in the cool, dry season and increasing to 94 per cent of it consumption in the hot, dry season.
It’s not so much the choice of plant species that separates the elephant from other animals, but the selection of plant parts. The African elephant concentrates on the bark, stem, and roots rather than foliage or fruit of plants. These choices reduce the elephant’s overlap of food selection with other animals.
The food choices of the African elephant can leave a large footprint. But rather than eliminating most of the woody plant component, elephant feeding habits may cause a compositional change among the woodland species due to their neglect of certain types of plants and favor of others.
From: Selective feeding by a mega-herbivore, the African elephant, Journal of Mammalogy, Vol. 93, No. 3, June 2012.
