Too much too soon? Risk factors for fear behaviour in foster kittens prior to adoption

Abstract

Many companion kittens spend their sensitive period for socialization (∼2–9 weeks of age) in foster care, and the quality of these early life experiences can impact behavioural development. This study aimed to improve early kitten care by using an online survey to investigate risk factors for fear behaviour in foster kittens prior to adoption (7–9 weeks of age) based on early management practices, foster parent personality traits, and evaluations of kitten behaviour. The main behavioural outcomes of this study were whether kittens showed caregiver-reported fear behaviour during interactions with unfamiliar people and unfamiliar objects just prior to adoption. Fear behaviour included displays of avoidance, freezing, crouching, ears back, piloerection, and aggression. We analyzed the impacts of kitten (n=235) and foster parent (n=72) characteristics, exposure to social stimuli (i.e., general handling, mimicking handling during a vet visit, exposure to people), and exposure to non-social stimuli (e.g., interactive toys, scratching material, different surfaces, etc.) provided. Using mixed logistic regression models, with foster parent as a random intercept to account for clustering at the foster home level, we found that kittens who were reported fearful at intake into foster care had significantly greater odds of displaying fear behaviours towards unfamiliar people and unfamiliar objects than kittens who were not reported fearful at intake. Additionally, kittens who received exposure to cognitive enrichment-based non-social stimuli had greater odds of displaying fear towards people compared to kittens who did not receive cognitive exposure. Kittens whose foster parent had a high score for emotional stability had greater odds of displaying fear towards people compared to those who had a low score for emotional stability. Further, kittens who received high exposure to social stimuli had reduced odds of displaying fear towards people than kittens who received low social exposure, as predicted. Some of these findings challenge recommendations for high amounts of exposure to social and non-social stimuli during early socialization. High social exposure was ineffective at reducing fear levels towards unfamiliar objects, and high cognitive enrichment-based non-social exposure appears to have exceeded kitten limits for optimal behavioural development. While appropriate socialization is beneficial for development, the current study highlights the need for further research to understand the impact of different socialization practices on kitten behavioural development, and the importance of accurately identifying when kittens are fearful and adapting socialization practices appropriately.