The cold-blooded cognition group is a brand new enterprise of the Department of Neurobiology and Cognition, University of Vienna. We are interested in all aspects of reptile and amphibian cognition. We work with a variety of species ranging from the tortoise to the salamander. If you are interested in any of this research please contact Anna Wilkinson (firstname.lastname@example.org) for further information.
Why study reptiles?
Reptiles, birds and mammals have all evolved from a common amniotic ancestor, and as such they are likely to share both behavioural and morphological traits. However, this common ancestor lived around 280 million years ago and so it is equally as likely that different traits and abilities may have emerged. Despite their clear importance for the study of cognitive evolution, very little research has investigated the learning abilities of reptiles. The few studies that have been conducted with reptiles found little evidence of impressive cognitive skills. However, many of these studies took place in unsuitable environments for the species tested (e.g. a cold room for a tropical reptile). As reptiles are ectothermic (cold-blooded) it is essential to provide them with an environmental temperature similar to that which they would experience in their natural habitat. Only then can their true cognitive abilities be tested. The cold-blooded cognition group is interested in all aspects of reptile cognition and studies their behaviour in the context of the behavioural ecology of the specific species tested.
Most of our work uses the red-footed tortoise (Geochelone carbonaria) as a model species. This species is native to Central and South America and lives on the fringes of tropical forests. They are naturally solitary and live a nomadic lifestyle, wandering about the forest floor searching for fallen fruit, leaves flowers and carrion. They are considered a medium to large size tortoise and can reach around 45 cm in length. They live for around 35 years. This species are particularly good for cognition work as they are more active than most tortoise species. They actively forage and adapt well to living in groups. At the department we have two groups of red-footed tortoises. One group lives in an enclosure inside a heated and humidified room, and the other group (consisting of the larger tortoises) lives in the same room, but shares their enclosure with marmosets (small South American monkeys). These species would naturally inhabit the same areas in the wild.
Our lizards are jewelled (or eyed) lizards (Lacerta lepida) and are native to South Western Europe. They have been generously leant to us by specialist breeders (http://www.chameleonnursery.gportal.hu/). They are the largest member of the Lacertidae, and can grow to more than 80 cm in length. Males get larger than females and are naturally territorial. Jewelled lizards are protected in Europe but breed well in captivity. They feed on large insects, small rodents and some will eat various kinds of sweet fruit.
We also work with a whole array of other reptiles including chameleons.
We are currently working on a project investigating spatial perception in the red-footed tortoise and other reptiles. We have recently examined the spatial abilities of the red-footed tortoise in a radial arm maze and found a similar level of performance to mammals; however the mechanisms controlling the behaviour appear to be quite different. We are currently working on elucidating exactly how tortoises navigate and under what conditions their behaviour differs from mammals. Further, we are also investigating whether the differences observed between our tortoises and mammals are common to all reptiles, or specific to our study species. As such we are running the tortoises and our jewelled lizards on identical tasks. Similarities and differences in behaviour can inform us about the evolution of the mechanisms underlying spatial navigation in reptiles.
|A radial arm maze task: What happens?|
The tortoise is placed in the middle of the maze. At the end of each of the arms is a hidden piece of food. In each trial the tortoise is allowed to make 8 choices. If he remembers each arm that he has been in he will get eight pieces of food. However, if he can’t remember the location of the arms he has already been in he will revisit arms where he has already eaten the food and his success will decrease. Mammals and birds use the relationship between landmarks around the maze to do this. This is known as a cognitive map. Tortoises appear able to use this mechanism as well, however, when the landmarks are poor they use a simple response based strategy (always go into the arm next to the one just left). This flexibility of behaviour has never been observed in mammals and birds.
The ability to follow the gaze of another organism is highly adaptive as it can alert an animal to the presence of food or of a predator. This ability is thought to have evolved as a result of social living and there is much evidence to support this in primates and a small amount in birds and other mammals. However this has never been tested in reptiles. We presented our red-footed tortoises with a task in which they saw another tortoise look up (at a light spot that could not be seen by the experimental subject). The question was: Would the tortoises look up in response to the other tortoise? They did. As our tortoises are naturally solitary it seems unlikely that selection pressure would have produced this ability. Therefore, the finding suggests that gaze following behaviour may have evolved in a common ancestor to mammals, birds and reptiles and that its presence in our tortoises may simply be a bi-product of their evolutionary history.
Reptiles are not very social animals. The red-footed tortoise is naturally solitary, exhibits no parental care and has little social interactions with conspecifics (other than mating). This makes this species ideal subjects to test hypotheses regarding the evolution of social learning. It has been suggested that social learning is an adaptive specialisation for social living and also that social living causes a general increase in cognition which allows an animal to learn from another’s actions. Both of these hypotheses suggest that a solitary species would be unable to learn from observing another’s actions. However, it is equally likely that an animal’s ability to learn socially is merely a reflection of that animal’s general ability to learn, irrelevant of its social environment. If this is the case then we would expect that the tortoises would be able to learn by observing the actions of a conspecific, and that is exactly what we found. This very exciting finding is the first evidence of social learning in a solitary species and suggests that social learning may merely be a reflection of an animal’s general learning ability.
The task: A detourWe presented tortoises with a detour task. Half of the animals watched a conspecific demonstrator complete the detour and half did not. The observer tortoises all completed the detour and reached the goal, whereas none of the control animals were able to.
Visual Perception and categorisation
Categorisation is probably the most fundamental component of cognition. It allows animals (and humans) to reduce the vast amount of information that is perceived daily, and takes advantage of the fact that objects within the same category share many properties and behaviours, and thus require similar responses (to flee, to hunt etc.). Most experiments investigating categorisation use photographic stimuli (see pigeon section). However, before embarking on these type of experiments with the tortoises, it is essential to question whether they are able to recognise the equivalence between real entities, and pictures of them. As such, the tortoises were trained to choose a piece of food over a non-food object (it did not take much training) and were then tested with photographs of the food vs. photographs of the object to see if they could still make this discrimination. We found that they could, later tests revealed that they did not see an equivalence between the real fruit and the photograph of the fruit, but actually perceived them in the same way.
Why study amphibians
Amphibians are a particularly interesting group to study as they undergo dramatic changes in their life cycle, both physical and in terms of their behavioural ecology. We are interested in the effect these changes have on their memory processes and behaviour.
We have 12 captive bred fire salamanders (Salamandra salamandra). These animals are highly endangered in the wild and are resident to central Europe. They are black with yellow spots, but can also be striped. This species is naturally nocturnal and territorial. They are have a very long lifespan, and can live up to 50 years in captivity. They are sit-and-wait predators and largely forage on insects, spider, worms and slugs.
We have run projects with frogs and plan to work with newts in the future too.
Effects of physical changes on memory processes
Amphibians, more than any other vertebrate go through enormous physical changes during their life cycle. The hormones that control the changes that the animals go through during metamorphosis also change the brain. However, little is known about how this affects their memory. We are working on a series of experiments examining the effects of metamorphosis on memory retention in the frog. In a similar vein we are running a set of experiments examining the effects of hibernation on memory retention in salamanders. The salamanders will be taught two tasks and then we will examine whether they can remember how to solve these tasks post-hibernation.
|The task: A T maze|
The salamanders are trained either to go left or to go right to reach a reward box. This is a damp, dark box in which they love to sit. Before making the decision to turn right or left the salamanders cannot see which is the reward box and which is an identical looking box that cannot be entered. Thus they must remember the spatial location of the reward box to successfully complete the task.
Dr. Anna Wilkinson
Anna is interested in all aspects of reptile and amphibian cognition. She instigated, set up and now heads the cold-blooded cognition group. If you are interested in this research please contact Anna via email: email@example.com
Julia is a PhD student working on the mechanisms underlying spatial navigation in reptiles.
Karin is a Masters student working on social learning in the red-footed tortoise.
Anne is a Masters student examining the effects of hibernation on memory in the fire salamander.
Isabella is an undergraduate research assistant and has been working on a project investigating gaze following in the red-footed tortoise.
Members of the Cold-Blooded Cognition Group
The Cold-Blooded Cognition group is hosted by the Biology of Cognition group at the University of Vienna. Its members have a diverse set of interests. They come from three different subject areas (biology, psychology and computer science) and four different universities.
Dr. Ulli Aust
Joanna Bryson (University of Bath)
Prof. Geoff Hall (University of York)
Prof. Ludwig Huber
Prof. Walter Hödl
Prof. Kim Kirkpatrick (Kansas State University)
Dr. Christian Palmers
Dr. Anna Wilkinson
Wilkinson, A., Chan, H. M., & Hall, G. (2007). A study of spatial learning and memory in the tortoise (Geochelone carbonaria). Journal of Comparative Psychology, 121, 412-418.
Wilkinson, A., Coward, S., & Hall, G. (2009). Visual and response-based navigation in the tortoise (Geochelone carbonaria) Animal Cognition. In Press.
Wilkinson, A., Mandl, I., Bugnyar, T. & Huber, L. (submitted to Biology Letters) Gaze following in the red-footed tortoise (Geochelone carbonaria): a reptile can coorient with a conspecific.
Wilkinson, A., Kuenstner, K., Mueller, J. & Huber, L. (submitted) Social learning in a non-social reptile.
Conference and Invited Presentations
Müller, J., Wilkinson, A., Künstner, K. & Huber L. (2009) What does a reptile see in a picture? Picture-object recognition in the red-footed tortoise (Geochelone carbonaria).
Paper at the ESF Conference on the Evolution of Social Cognition, Budapest, Hungary.
Wilkinson, A., Chan, H.M. & Hall, G. (2007). Spatial learning in the tortoise (Geochelone carbonaria) Paper at the International Conference of Comparative Cognition, Florida, USA.
Wilkinson, A., Chan, H.M., Coward, S. & Hall, G. (2008). More spatial learning in the tortoise (Geochelone carbonaria). Paper at the Annual Symposium for Associative Learning, Wales, UK
Wilkinson, A. (2008). Comparative social cognition: from reptiles to primates. Univeristy of Bonn, Department of Psychology, Bonn, Germany.
Wilkinson, A., Künstner K., Müller, J., & Huber, L. (2009). Social learning in a non-social reptile: Can a tortoise (Geochelone carbonaria) learn from the actions of a conspecific? Paper at the ESF Conference on the Evolution of Social Cognition, Budapest, Hungary.
Wilkinson, A. (2009). Animal social cognition: what does an animal need to know to learn from another? Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, Netherlands.