Development of Social Behaviour in Four Litters of Dogs (Canis familiaris)

Abstract

The development of social behaviour in 4 litters of dogs was observed without interfering with the puppies from birth to 8 weeks of age. Direct and continuous observation was combined with video recording. Three of the litters were observed during one session of 2 h once a week, and the fourth litter during one session of 40 min twice a week. Social interactions were divided into 1) investigation of litter mates (licking, sniffing or investigating orally), 2) social play, 3) and interactions in which agonistic elements (dominance postures, threats, bites or submission) were displayed. The different forms of social interactions appeared for the first time when the puppies were between 14 and 21 days of age. Social investigation appeared first and was followed by play and agonistic interactions. From week 5, differences between the puppies in the tendency to initiate social play and agonistic interactions emerged. Generally, within the litters individual differences were consistent over weeks 6-8 (positive correlations between weeks), whereas the tendency in the puppies during these weeks were negatively correlated with those of week 3 (play) or weeks 3 and 4 (agonistic interactions), indicating a rebound effect for both play and agonistic behaviour. No significant correlations, however, were found for social investigation. More often than expected males played or engaged in agonistic with other males, whereas these behaviours occurred less often than expected between females. Both males and females, however, preferred male partners for agonistic interactions. No sex differences were found in the direction of social investigation. Agonistic behaviour was often responded to by play and play was often responded to by agonistic behaviour, and the results indicated that before 8 weeks of age differences in social behaviour between the puppies were already established.

Sammendrag

For at følge udviklingen af den sociale adfærd blev 4 kuld hundehvalpe observeret uden indgriben i deres hjemmemiljø fra fødslen til 8 ugers alderen. Tre af kuldene blev observeret kontinuerligt i 2 timer en gang hver uge, og det fjerde kuld i 40 min 2 gange om ugen. Samtidigt blev hvalpenes adfærd optaget på video. Den sociale adfærd blev inddelt i 1) undersøgelsesadfærd rettet mod kuldsøskende (slikken, snusen eller oral undersøgelse), 2) social leg samt 3) interaktioner, der indeholdt agonistiske elementer så som dominanspositurer, trusler, bid eller underkastelse. De forskellige typer af social adfærd fremkom, da hvalpene var mellem 14 og 21 dage gamle. Social undersøgelsesadfærd sås først og blev fulgt af leg og agonistisk adfærd. Forskelle mellem hvalpene med hensyn til deres tendens til at indlede leg samt agonistiske interaktioner begyndte at udvikle sig i uge 5. Leg og agonistiske interaktioner mellem hanhvalpe forekom hyppigere end forventet. Derimod forekom disse adfærdsformer mindre hyppigt end forventet mellem hunhvalpe. Hos begge køn sås dog en præference for hanhvalpe som partnere i forbindelse med agonistiske interaktioner. I forbindelse med social undersøgelsesadfærd sås ingen kønsforskelle m.h.t retningen af interaktionerne mellem hvalpene. Generelt var de fundne forskelle mellem hvalpene med hensyn til deres tendens til at indlede leg samt agonistiske interaktioner konsistente (positiv korrelation) gennem uge 6–8. Derimod var frekvenserne gennem disse uger negativt korrelerede med frekvenserne i uge 3 (leg) eller uge 3 og 4 (agonistiske interaktioner), hvilket tyder på en rebound effekt for både leg og agonistisk adfærd. Tilsvarende signifikante korrelationer blev ikke fundet for social undersøgelsesadfærd. Agonistisk adfærd blev ofte besväret med leg og leg blev ofte besväret med agonistisk adfærd, og resultaterne tydede på, at forskelle mellem hvalpene med hensyn til deres sociale adfærd var udviklet før 8 ugers alderen.