Not all mice are equal: welfare implications of behavioural habituation profiles in four 129 mouse substrains

PLoS One. 2012;7(8):e42544. doi: 10.1371/journal.pone.0042544. Epub 2012 Aug 3.


Safeguarding the welfare of animals is an important aim when defining housing and management standards in animal based, experimental research. While such standards are usually defined per animal species, it is known that considerable differences between laboratory mouse strains exist, for example with regard to their emotional traits. Following earlier experiments, in which we found that 129P3 mice show a lack of habituation of anxiety related behaviour after repeated exposure to an initially novel environment (non-adaptive profile), we here investigated four other 129 inbred mouse substrains (129S2/SvPas, 129S2/SvHsd (exp 1); 129P2 and 129X1 (exp 2)) on habituation of anxiety related behaviour. Male mice of each strain were repeatedly placed in the modified hole board test, measuring anxiety-related behaviour, exploratory and locomotor behaviour. The results reveal that all four substrains show a lack of habituation behaviour throughout the period of testing. Although not in all of the substrains a possible confounding effect of general activity can be excluded, our findings suggest that the genetic background of the 129 substrains may increase their vulnerability to cope with environmental challenges, such as exposure to novelty. This vulnerability might negatively affect the welfare of these mice under standard laboratory conditions when compared with other strains. Based on our findings we suggest to consider (sub)strain-specific guidelines and protocols, taking the (subs)train-specific adaptive capabilities into account.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animal Welfare*
  • Animals
  • Arousal / physiology
  • Avoidance Learning / physiology
  • Behavior, Animal / physiology*
  • Corticosterone / blood
  • Crosses, Genetic
  • Exploratory Behavior / physiology
  • Feeding Behavior / physiology
  • Female
  • Habituation, Psychophysiologic*
  • Latency Period, Psychological
  • Locomotion / physiology
  • Male
  • Mice
  • Mice, 129 Strain
  • Risk Assessment


  • Corticosterone

Grant support

The work was financially supported by the Faculty of Veterinary Medicine, Utrecht University. The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.