Environmental enrichment (EE) is used to improve the life of captive animals by giving them more opportunities to express species-specific behaviours. Zoo elephants are one of the species that is in great need of EE because their environment is often barren. Before making EEs permanent, however, it is wise to test first if it works as intended, to save time and money.

Maximum price paid is one measure that can be used to assess if an animal has any interest in an EE at all. To be able to say something about the value of an EE to the elephant it has to be compared against something of known value. Food is one the things most often used as a comparator since it is very important to all animals.  

The aim of this study was to investigate if the maximum price paid concept could be used to measure the value of EEs for the two female Asian elephants at Kolmården and to find an operant test suitable for them for the experimental trials. Three series of food trials were done with each elephant, where they had to lift weights by pulling a rope with their mouth to get access to 5kg hay. The elephants paid a maximum price of 372 and 227kg, respectively. Now it has to be tested with other resources as well to be able to say for certain that maximum price paid can be used to find the most suitable EEs for these elephants. The maximum price the elephants paid for access to the hay was not stable across the three series of trials; therefore, it is recommended that the food trials are repeated close in time to the EEs to be tested. The willingness by which these elephants performed the task makes it worthwhile to further pursue this approach as one of the means to improve the well-being of zoo elephants.