Publishers of the Journal of Heredity
Join the AGA

EECG Embarkation: Pairing Behaviour and Genetics to Uncover the Secret Social Lives of Lizards

**The AGA grants EECG Research Awards each year to graduate and post-doctoral researchers who are at a critical point in their research, where additional funds would allow them to conclude their research project and prepare it for publication. EECG awardees also get the opportunity to hone their science communication and write three posts over their grant tenure for the AGA Blog. In the first in the series, our EECG awardees write about their research and their interests as an ’embarkation’.


About the Author: Dr. Julia Riley is a behavioral and evolutionary ecologist, and is an NSERC Postdoctoral Fellow at Dalhousie University in Nova Scotia, Canada. She studies the animal behavior, ecology, and natural history of a variety of animals, with a focus on amphibians and reptiles. Follow Julia on Twitter @jr4science or check out her website.



I am currently an NSERC Postdoctoral Fellow hosted in Dr. Hal Whitehead’s lab at Dalhousie University, Nova Scotia, Canada. My background is in ecology. I’ve always been captivated with the wonders of the natural world and have been particularly fascinated by amphibians and reptiles. My research on the natural history of herpetofauna has led me more broadly into the fields of animal behavior, evolutionary ecology, and conservation, which I have been lucky to study in Canada, Australia, and South Africa. The current focus of my research is to understand the evolution of sociality through the use of reptilian model systems and I ask questions like: What are the evolutionary origins of family living? How do reptiles benefit from living in groups or with family? What is the nature of reptilian social behavior? Currently, I am based in South Africa studying the diversity of sociality within the African Cordylidae. You can check out more information about the social lives of reptiles and my research on my website or the Whitehead Lab website.

I am very grateful for the support from the American Genetic Association’s EECG Award to complete my project on the sociality of African cordylid lizards. There is great variability in social systems across the animal kingdom, and it is a trait that strongly influences a species’ biology and ecology. One group with only an emerging understanding of their social lives is non-avian reptiles. For most species, the social system is unknown. But over the last decade, in the Egernia-group of Australian skinks, a broad range of social systems have been discovered; with species varying from largely solitary to family-living (While et al. 2015). Advances in genetic techniques are likely one reason for this development, as well as researchers integrating behavioral study and a genomic approach, because describing a social system requires data on how social interactions relate to the genetic structure of a population (Whiting and While 2017). Lizard sociality is best studied in the Egernia-group of skinks, but it is likely that family living has evolved convergently in other lizard clades on other continents.

Figure 2. The four cordylid lizards in my study, which vary in their conspecific grouping behavior. From left to right: the Southern Karusa Lizard, Peers’ Nama Lizards, Large-scaled Girdled Lizards, and a basking group of Armadillo Lizards. Photos credited to Julia Riley.

For the past three years, I have been studying the diversity of sociality within the African Cordylidae. This lizard clade has long intrigued scientists because many species live in aggregations (Mouton 2011). I have been studying four key cordylids to characterize their sociality, with a specific focus on testing for the presence of family living. In the field, through behavioral observation, I have found that my four cordylid study species vary in their conspecific grouping behavior. The Southern Karusa Lizard (Karusasaurus polyzonus) was the least gregarious, and was solitary in most behavioral observations. Peers’ Nama Lizard (Namazonurus peersi) was observed aggregating 51% of the time and was seen in small groups of juveniles and/or adults. Large-scaled Girdled Lizards (Cordylus macropholis) were highly aggregative; they were observed in a group, which varied in size to up to 12 individuals, 84% of the time. Armadillo Lizards (Ouroborus cataphractus) represented the extreme of gregariousness in our study. This species was most often seen in large groups of up to 27 individuals that were multi-generational and consistent over time in structure and membership. At this point in my study, all the field data has been collected and my tissues samples are currently being genotyped. Relating the behavioral and genotypic data for each species will allow me to examine whether these species live in family groups. AGA’s support has allowed me to move forward with the next steps of this research project, and I am very excited to be able to see whether or not kinship plays a role in cordylid social behavior soon!



Mouton PLFN (2011) Aggregation behaviour of lizards in the arid western regions of South Africa. African Journal of Herpetology. 60: 155-170.

While GM, Chapple DG, Gardner MG, Uller T, Whiting MJ (2015) Egernia lizards. Current Biology. 25: R593-R595.

Whiting MJ, While GM (2017) Sociality in Lizards. In: D Rubenstein, P Abbot (eds), Comparative Social Evolution. Cambridge University Press, Cambridge.

Subscribe to Our Blog