The suckling behaviour of 327 piglets from 39 litters of primiparous domestic sows Sus scrofa f. domestica was analysed regarding the development of territorial suckling consistency during a 5-week suckling period. Additionally, the consistent use of a certain teat pair (1–7) during the whole suckling period was related to weight gain within the suckling period and to social dominance after weaning and mixing of the piglets. The piglets increased their suckling stability consistent with a three-parametric exponential model delivering a time-dependency that is typical for learning curves and which may be a useful methodological approach for studies on behavioural ontogeny. Thus, the development of suckling stability can be regarded as a continuous learning process. After extremely rapid learning within the first 4 days of life a moderate increase of suckling consistency with final stabilization occurred within the second week. After this time, the piglets maintained a high suckling consistency of about 95% up to the end of the observed suckling period. The anterior teats were preferred, whereas piglets suckling at the posterior teats showed a tendency to have lower weight gains and poorer dominance values. However, the lowest suckling stability (consistency) was found with piglets occupying the middle teats. The study shows that individual differences (e.g. weight gain, position in a social hierarchy) have their roots in early ontogenetic characteristics of the neonates (e.g. suckling behaviour, physical strength). The results are discussed with regard to findings and interpretations of behavioural ontogeny in pigs.