Social play fulfills an important function in creating and maintaining relations between siblings. However, its relationship with the intralitter social processes is poorly understood. It was noticed that, in Eur asian lynx (Lynx lynx) litters, sex differences in social play are absent in the first 2-3 months of life. It was found that the most intense periods of play behavior (at an age of 9 and 12 weeks) coincide with periods of aggression. Gradual change in play interactions, which require close physical contact by play elements with increased motor activity, are described. This reflects the changes in the relevance of certain skills of lynx cubs as they grow older.

No abstract

In many mammals, play is one of the most conspicuous behaviors during early development, but with notable inter‐individual variation even within the same litter. We investigated predictors of such variation in the Eurasian lynx (Lynx lynx), with a focus on potential effects of cubs' early body mass on the frequency of initiating play. We studied 45 cubs from 18 litters, kept in enclosures together with their mother. Observations started when cubs began to leave the natal den (around postnatal day 30) and lasted until weaning (around postnatal day 90). Individual differences in play were consistent over time, across all cubs as well as among littermates. The initiation of different play categories – with siblings, with the mother and solitary play – was positively associated and showed a similar developmental pattern. Cubs' body mass was positively associated with the frequency of play events; heavier cubs initiated play more often than lighter ones. This is consistent with the surplus resource theory, that is, that heavier young might have more energy resources available to allocate to play. Alternatively, lighter cubs may have initiated play less often to avoid asymmetrical rough‐and‐tumble interactions with their heavier siblings. Additionally, we found that offspring from middle‐age mothers initiated play more frequently than offspring from younger or older mothers. As cubs from middle‐age mothers had higher growth rates, this finding is again consistent with the surplus resource theory. Important questions for future research are whether such stable individual differences in play during early development correlate with other behavioral traits and translate into individual differences in behavior in later life.

Social play in young mammals reflects behavioral development, play can be affected by differences in development timing and species biology. We compared social play frequency changes in three felids: Eurasian lynx (Lynx lynx), Amur subspecies of leopard cat (Far-Eastern wildcat) (Prionailurus bengalensis euptilurus) and domestic cat (Felis catus). Social play is often expected to increase social tolerance and cohesion in a litter. Socially living domestic cat had contact and non-contact social play rates at the same level as solitary lynx and leopard cat. Whereas lynx differed from the other felids in lower social play rates at the age from one to one and a half month. Two types of social play were changing differently. Non-contact play rates, attributed to predatory skills development, were synchronized among species by age of kittens. Whereas contact play changes, attributed to communication development, were sensitive to the developmental stage. Contact play intensified in lynx much later than in the other felids probably due to a later onset of weaning. The period of extraordinary low contact play rates coincided with the onset of spontaneous sibling aggression, unique for lynx. After a period of spontaneous sibling aggression contact play rates in lynx increased to the level that other felids had. Observed social play changes and differences reflect development timing and species-specific features in felids.

No abstract