The olfactory and auditory capabilities of dogs (Canis lupus familiaris) for locating different quantities of food

Although some animals, such as elephants, can use olfaction to discriminate quantities of food, previous research suggested dogs cannot smell the difference between quantities of hot dog slices. In the experiments reported here, dogs were allowed to smell two opaque containers under which were placed different numbers of hot dog slices, and then were allowed to make a choice between containers. In Experiment 1, dogs chose between one and five hot dog slices and chose the larger quantity at an above chance level. In Experiment 2 and Experiment 3, I tested whether dogs conformed to the distance effect and/or the ratio effect when smelling quantities and found no evidence of either effect. In a fourth experiment, I tested whether the type of food used influenced the performance of dogs and found that the performance of dogs was higher when hot dog slices were used as reinforcement rather than kibble pieces. In the fifth experiment, I tested whether dogs could hear the difference between quantities of hot dog slices and found no evidence of quantity discrimination in this modality. These results suggest that dogs are capable of using olfaction to discriminate quantities of food based on amount, but not number, of hot dog slices