Developmental trajectories of cognitive traits in meerkats match socio-ecological demands

Understanding cognitive development is fundamental to contextualize adult cognitive phenotypes, and thus the operational pathways for cognitive evolution. The ontogeny of specific cognitive traits is likely influenced by both population-wide pressures, such as ecological demands, and individual-specific factors, including early life experiences. To properly investigate cognitive variation, we must therefore identify species-level developmental trajectories and individual variation from normative ontogeny in natural populations. Towards this goal, we used a longitudinal approach to study the ontogeny of three distinct cognitive traits (physical problem-solving skills, inhibition control, and spatial cognition) in 28 wild meerkats ( Suricata suricatta ), assessed at five key developmental stages from early life to sub-adulthood. Using mixed-effect models, we found that rates of development (learning curves) differed among traits, reflecting variation in the timing of socio-ecological pressures, like the onset of independent foraging and adult cooperative behaviours. Within individuals learning curves, baseline abilities (without the effect of development) or performance at specific time points among the different traits did not correlate, suggesting independent processes underlying performance in the presented tasks. Inhibitory control did not display substantive individual variability in baseline performance and learning curves, possibly reflecting reduced genetic variation or developmental canalization. In contrast, spatial cognition and physical problem-solving both exhibited substantial individual differences in baseline performance and learning curves, suggesting that these traits may be under distinct selective timescales and pressures. Among the measured traits, only physical problem-solving showed consistency in individual performances over time, a pattern that emerged close to the onset of nutritional independence, reflecting critical early timing of foraging competence in this species. Further research should investigate the factors underlying individual differences and their adaptive value.