Stereotypic behavior in mink is an animal welfare problem in the sense that it concerns animal protection groups and the public opinion. Stereotypies probably also signifies a lack of possibilities to express some behavioral wish or need in the animal. However, it is at this point still not determined whether stereotypies, per se, are detrimental to the welfare of the animals performing them. Work done on mink and other animals suggests that high stereotyping animals are physiologically "calm", e.g. low in cortisol, whereas the opposite is the case for low stereotyping animals. This suggests that stereotypies could be an active coping strategy, a way to lower the anxiety or stress perceived in the situation that the animal finds itself in. It should be kept in mind, however, that other factors, such as a relatively higher metabolic rate, could explain the low cortisol levels in very active/stereotyping animals. Although it is possible to breed a low stereotypy line of mink, it seems undesirable to breed a mink which may look calm, but may suffer from high physiological stress levels.

In order to investigate whether the converse relationship between stereotypic activity and physiological state also exists in mink, the following experiment was set up. Six female mink, selected for being high stereotyping (HS) and six selected for low stereotyping levels (LS) were implanted with a radio transmitter, continuously transmitting heart rate and body temperature data, while housed in standard mink cages. Cortisol was measured on 24h urine samples and the mink's behavior was recorded with a time-lapse VCR. The resulting video tapes were analyzed using a custom-made program encoding behavior on a Husky handheld computer for later analysis on a PC.

After an initial period of base line measurements, the mink were confined in standard traps for an hour every day for nine days. During this period the measured physiological variables related to stress declined for both groups, suggesting that habituation had occurred. Furthermore, the HS group was more reactive (measured on cortisol) than the LS group.