Research

Understanding how behaviours evolve is a long-standing goal in evolutionary biology. Due to the fundamental nature of this topic, behavioural evolution is a naturally recurring theme in all my research projects.

Animal domestication provides an extraordinary framework to address question on behavioural evolution, as selection upon behaviour likely initialized domestication. I have therefore been using domestication as a model to study behavioural evolution for over a decade now (see Domestication research section for more information).  In this line of work I am particularly focused on using the dog (Canis lupus familiaris) as a model species for studying behvavioural evolution. The dog was domesticated from now extinct wolf (Canis lupus) lineages 40,000-15,000 years ago. The rich insights we have about the dog's evolutionary history, the advanced genetic tools specifically developed using this species, and the fact that the majority of present-day dogs are living as highly adaptable free-ranging individuals in various ecological niches, makes the dog an intriguing model for behavioural ecology and evolution studies.

I have a great interest in how complex behaviours evolve. One such example is behavioural syndromes, where two or more behavioural traits are correlated and change together. Currently I am working on a project together with my collaborator, Arild Husby from Uppsala University, on the heritability of behavioural syndromes in dogs. The behavioural syndrome embedded in the domestication syndrome is another example of work I have done on complex behavioural evolution, which is described in more detail in the Domestication research section below.

Lastly, for my postdoc working with Charlie Cornwallis at Lund University, I addressed question on social evolution and how cooperation has evolved among non-kin birds using comparative analyses and rigorous sampling on various behavioural traits and ecological parameters.

A central topic in Tinbergen's research was that of behavioural development. Does behaviour in the individual change over time and how do various environmental factors affect the individual during different life stages? I share the interest in questions on behavioural ontogeny and address this research topic from different angles.

Quantifying the same behaviours at different time points in an animal's life can tell us something about the repeatability and consistency of behavioural expression. Detailed insights on behavioural ontogeny can provide knowledge on which phenotypes might be adaptive and thus be important from an evolutionary perspective. For instance, subjecting wolves and dogs hand-raised under identical conditions to temporal novel object tests, we have shown that dogs, but not wolves, lose their fear of novelty with age. This indicates that neophobia continues to have an adaptive value in wolves, whereas dogs now live in an environment where this behavioural trait is less important.

Currently, I am working with several aspects of behavioural ontogeny, including the ontogeny of behavioural syndromes using large-scale standardized data, how complex social behaviours (e.g. play, dominance, social networks) develop and relate to each other. For my FORMAS Early Career Grant I will be develop a large-scale project investigating the importance of social environment during early life stages for behvaioural expression later in life.

Domestication of the dog (Canis lupus familiaris) from now extinct wolf (Canis lupus) lineages likely occurred 40,000-15,000 years ago, making the dog the first domesticated species. Present-day dogs live vastly different lives than wolves, with their social environment, reproductive opportunities and food resources being significantly altered and heavily influenced by humans. It therefore seems likely that behaviour has changed quite dramatically during the course of dog domestication and the current topic of much domestication research is therefore to compare the behaviour of wolves and dogs. 

However,  it remains important to also disentangle which traits we selected for at the very beginning of dog domestication. Which behavioural traits are similar between wolves and dogs and thereby show signatures of selection on standing variation in ancestral wolf populations? These traits are likely rare in occurrence among present-day wolves, but nevertheless crucial for us to identify in order to adequately understand the dynamics of the early domestication process and the behaviour of our dogs. Would you for instance expect that fetching, the game we most often engage in with our dogs, to be a behavioural trait that evolved during domestication or an original wolf trait?

Lastly, my work on domestication also includes empirical testing of the Domestication Syndrome Hypothesis, which predicts that a range of morphological, physiological and behavioural traits change together during domestication as correlated traits. However, the foundation of this hypothesis, and widely applied paradigm, was mainly based on observations, has rarely been tested, and is currently the subject of great debate. In 2019, colleagues and I did some pioneering work using a large data set on 76,000 dog breeds to test the behavioural part of the domestication syndrome hypothesis. We found that breeds with a recent origin (< 200 years ago, i.e. “modern” breeds) lack the expected behavioural correlations, while breeds with an earlier origin (~500 years ago, "ancient" breeds) express the correlations of the domestication syndrome. In a follow-up study we found that classic morphological domestication syndrome  traits (i.e. floppy ears, curly tails, white pigmentation) neither covary with, nor predict the strength of, expected behavioural correlations in any dog breed. These findings fundamentally challenge the rigidity of the domestication syndrome hypothesis for dogs, and other animals, as we can no longer assume that the domestication syndrome is present in all present-day domesticated lineages. Currently, I am in the process of developing new projects to further my work to gain novel insights on the domestication syndrome.

Of the world's estimated one billion dogs, 80% are not pets, but dogs living in widespread free-ranging, free-breeding groups in Eurasia, Oceania, Africa and the Americas. While studies on these dogs still remain sparse, it is clear that that free-ranging dog populations express substantial variation in their behavioural ecology across their global range. This makes free-ranging dogs an excellent, yet underutilized, model species for the study of how climate and anthropogenic change affects behavioural ecology and evolution. Furthermore, detailed studies of free-ranging dog behaviour are needed  to establish what entails natural dog behaviour.

I have used different field-based techniques to gain insights on spatial behaviour on several animal species. For instance, I have used radio-telemetry to establish home range sizes, space use and dispersal in a wild population of swift foxes (Vulpes velox) in Colorado. While working in a privately owned nature reserve in South Africa, we used extensive camera trapping to obtain data on African leopard (Panthera pardus pardus) distribution within for accurate population estimates for conservation purposes. Finally, for my postdoc project I combined state-of-the-art bio-logging methods with physiology and behavioral ecology to investigate how stress affects behavioral expression and group dynamics in wild-living vulturine guinea fowl (Acryllium vulturinum).