Social behaviour of endangered European mink (Mustela lutreola) litters in captivity

• A detailed ethogram of social behaviour among the European mink cubs was compiled.
• Social behaviour of the juveniles in captivity was diverse and included all expected elements.
• Inter-cub aggression did not increase with the age of the juveniles.
• There were no litters with outlying behaviour, and the behaviour did not depend on the parameters of the litter.
• No evidence was found to ascribe the abnormal behaviour of the captive-born adults to conditions experienced during the litter period.

In litter-bearing mammals, the environment and social interactions during early life often have a substantial effect on future behaviour of the animal. Most information though derives from lab rodents, pets or farm animals while comparable data are scarce for non-domesticated species, and endangered carnivores in particular. In this study, we focused on social behaviour of juvenile European mink, with the practical aim to provide information for enhancing the ex-situ breeding programme of this critically endangered species. As the first step, we compiled a detailed ethogram of social behaviour observed among the European mink cubs. For the 13 captive born litters available, we then systematically recorded the relative duration of different types of behaviour during a two months period. The behaviour of the captive cubs was found to be diverse, containing all elements characteristic of congeneric mustelids, with no indication of litters deviating from the typical pattern. In all broods, a considerable and approximately equal share of time was allocated to social play, a suggested indicator of positive welfare. Aggressive behaviour of the mother towards her offspring was minimal when the cubs were young and, increased only with the litter dispersal period approaching. Bites between the cubs during play fighting did not increase with the age of the juveniles. We found no evidence that captive environment adversely affects the behaviour of the juveniles during the first months of their life.