Odour information enables African elephants to detect differences in food quantity from afar

African elephants (Loxodonta africana) can rely on olfactory cues to guide foraging decisions. While odour can play a key role in indicating food quality, the potential for elephants to use odour to discriminate between food quantities from distance is unknown. Using a giant Y-maze, we examined the extent to which four captive elephants could use odour cues to discriminate between patches containing between 100 and 1000 g of food from 9.5 m away. As food quantities in the two patches became similar (proportional difference declined, ratios increased), the elephants' ability to discriminate between them declined. In line with Weber's Law, the elephants were only able to select the greater food amount when the absolute (>600 g) and proportional (>0.86) differences (i.e. discrepancy) were large, and the ratios were small. Previous research suggests that 600 g corresponds to approximately 6-10 trunk loads of grass or 16-29 trunk loads of woody vegetation leaves. Our findings suggest that African elephants could use olfactory cues to facilitate between-patch foraging decisions based on relatively fine-scale differences in food availability. Understanding this and linking it to patch selection may provide broader insight into elephant impacts on plant communities.