This study investigated the nutritional ecology of forest elephants in Kibale National Park, Uganda relative to crop-raiding behaviour, and examined nutritional differences between crops and food consumed by wild elephants. An index of dietary nutrient concentration was determined by quantifying the species and parts of plants consumed along feeding trails, collecting food items, and analysing foods for energy, fibre, protein, minerals and secondary compounds. Frequency of crop raiding was quantified over 13 mo. Energy and protein concentration was within suggested levels, but concentrations of several minerals, particularly sodium, were low relative to requirements based on captive elephants and values reported for other wild populations. The very low sodium concentrations of Kibale elephant diets and low availability of alternative sodium sources, such as soil or water, suggest that sodium drive is very likely in this population. Crops consumed by Kibale elephants had higher Na concentrations and lower concentrations of fibre and secondary compounds than wild diets. The known attraction of elephants to mineral sources throughout their range and the low mineral concentration of leaves, fruits, bark, and stems consumed by forest elephant in this study suggest that mineral nutrition is likely to be an important factor driving elephant behaviour and patterns of habitat use.

The stature of forest elephants Loxodonta africana cyclotis was determined at the Petit Loango Reserve over 14 months from January to December 1998 and May to June 1999 using three measures: shoulder height, hind footprint length and boli diameter. The shoulder height of 53 identified elephants was measured using photogrammetric methods. The minimum estimated shoulder height was 69 cm from a young calf, and the tallest animal was 216 cm. Hind footprint length and boli diameter data were collected from unidentified individuals. The minimum footprint size was 12.5 cm and the largest 35.3 cm. Boli diameter ranged from 4.0 to 16.0 cm. A comparison of the size categories with those of savanna elephants in Amboseli National Park, Kenya, suggested a similar distribution of size, age and population structure, despite a marked difference in overall stature. These are the first data for measures of African forest elephant size compared to African savanna elephant size. Such data may add morphological evidence supporting recent genetic work suggesting that African forest elephants be re-classified as a distinct species from the African savanna elephant.