Affordable Access

Lizards in 'nuclear families': a novel reptilian social system in Egernia saxatilis (Scincidae).

Authors
  • O'Connor, D
  • Shine, R
Type
Published Article
Journal
Molecular ecology
Publication Date
Mar 01, 2003
Volume
12
Issue
3
Pages
743–752
Identifiers
PMID: 12675829
Source
Medline
License
Unknown

Abstract

Recent research has revealed unsuspected complexity in social organization among squamate reptiles. In particular, large Australian scincid lizards of the genus Egernia have been reported to occur in large aggregations of closely related individuals. However, the 'nuclear family' structure found in many other 'social' organisms (especially birds) has not been reported from reptiles. Our field studies on black rock skinks (Egernia saxatilis) in southeastern Australia document exactly this pattern. We quantified group composition using behavioural observations at regular intervals over three field seasons, and took tissue samples for parentage analysis. On the focal rock outcrop 72% of lizards were typically found as part of a stable social grouping, with individuals physically associated with other group members in a third of observations. Eighty-five per cent of juveniles lived in social groups, 65% in family groups with at least one of their parents (including 39% with both parents as revealed by parentage analysis of five microsatellite loci). Broader sampling in surrounding areas revealed similar patterns of group size, composition and relatedness. Overall, of the groups that contained more than one adult, 83% contained a single adult pair. Long-term monogamy and group stability were evident from our genetic data, with up to three annual cohorts of full-sib offspring living with their biological parents. Our data expand the range of social systems known for reptiles, and reveal strong convergence towards 'nuclear family' systems in distantly related vertebrates.

Report this publication

Statistics

Seen <100 times