Do African elephants use visual cues of food quantity when making foraging decisions?

African elephants ( Loxodonta africana ) are ecosystem engineers that can have dramatic impacts on the landscape through their feeding. Therefore, understanding how elephants make foraging decisions provides insight into what drives both spatial and temporal aspects of these impacts. Previous studies have found that African elephants may use olfactory cues and leaf colour (index of food quality) when making foraging decisions between individual plants and patches. However, little is known about the extent to which they may use visual cues of food quantity such as canopy size and leaf density of trees while foraging. To address this knowledge gap, we conducted a series of visual-based choice experiments with four semi-tame adult African elephants to test both small- and large-scale foraging decisions. These experiments were conducted using (1) solid black circles printed on canvases (i.e., 1 m, 0.7 m diameter), and (2) black and white circles printed on canvases that differed in density (i.e., 25%, 50% and 100% shaded). Prior to the experiments, we trained the elephants to select the larger circle and the greater densities in paired choices. We found that the elephants were able to discriminate differences in size and density up to a distance of 5 m, but not beyond (i.e., 10, 20, 40, 80 m). These findings suggest that foraging decisions made by African elephants over small spatial scales (i.e., within patches) could be influenced by both visual and olfactory cues. However, beyond 5 m (i.e., between patches), elephants likely rely primarily on olfactory cues.