Patterns and predictors of inter-litter differences in rabbit pup locomotor activity, based on an automatized...

Area of Science:

• Animal Behavior
• Developmental Biology
• Mammalian Physiology

Background:

• Sibling interactions in domestic rabbit (Oryctolagus cuniculus) litters are well-studied.
• Limited knowledge exists on inter-litter variations in early postnatal pup activity and their underlying causes.

Purpose of the Study:

• Investigate drivers of inter-litter differences in pup activity patterns.
• Predict lower activity in litters with lower birth body mass and milk intake.
• Explore activity as a coping strategy for energetic constraints.

Main Methods:

• Developed and validated an automated method for assessing pup locomotor activity using video frame dissimilarities.
• Monitored 2-3-day-old rabbit pups' activity within the litter huddle.
• Analyzed activity patterns in relation to starting body mass and daily milk intake.

Main Results:

• Confirmed a U-shaped litter activity pattern, peaking around daily nursing times.
• Inter-litter differences in starting body mass and milk intake interactively affected locomotor activity.
• Heavier pups with higher milk intake showed greater activity, but only during the mid-interval when litter activity was low.

Conclusions:

• Pup body mass and energy intake significantly shape inter-litter activity differences.
• These factors, linked to maternal traits, influence pup behavioral strategies.
• Activity levels are decoupled from body mass and milk intake shortly before and after nursing.