The three elephants were tested on their long- term odor memory by using two different odor combinations that they had learned previously. The testing was carried out after a period of recess.

All three animals performed at least as good in the two sessions after the three-week recess compared to the two last sessions with n-amyl acetate vs. anethole before the recess. On the very first 10 decisions after the recess all three elephants scored 10 out of 10 correct decisions. Similarly, all three animals performed at least as good in the two sessions after the 1-year recess compared to the two last sessions with ethyl butyrate vs. 2-phenylethanol before the recess. Here, too, on the very first 10 decisions after the recess all three elephants scored 10 out of 10 correct decisions.

This clearly demonstrates that the animals did not quickly re-learn the reward values of the rewarded and the unrewarded odor, but that they indeed remembered them over these periods of time.

Since elephants are long-lived it is near at hand to assume that they should also have a good long-term memory to be able to survive in nature. They have to travel over long distances and should benefit from remembering details of the environment, e. g. water and food resources (Hart and Hart 2007; Hart et al. 2008) but they should also be able to recognize individuals from the social group.