Â鶹ÒùÔº

New study shows tortoises experience feelings similar to our own

Animal behavior and cognition experts at the University of Lincoln, U.K., have made new discoveries about reptile sentience which could reshape how they are cared for in captivity.

The pioneering study puts forward compelling evidence that red-footed tortoises (Chelonoidis carbonaria) experience long-term mood states, in a similar way to mammals and birds. This discovery marks a significant step forward in understanding the subjective experiences of reptiles as it challenges long-held assumptions, bringing major implications for animal welfare.

The team studied 15 red-footed tortoises using a cognitive bias test—an approach developed in humans which reveals whether individuals respond optimistically or pessimistically in their judgment of ambiguity, depending on their background mood.

This test, commonly used in mammals and birds, evaluates how animals interpret ambiguous situations, acting as a window into how they feel. The researchers found that tortoises housed in enriched environments were more likely to judge ambiguous situations optimistically, suggesting a positive mood.

The group additionally observed the tortoises' behavior in anxiety-related tests involving exposure to novel objects and unfamiliar environments. The tortoises that showed more optimistic decision-making in the cognitive bias test also displayed less anxious behavior in response to novelty, reinforcing the link between mood and behavior. The research is in the journal Animal Cognition.

This research adds to a growing body of evidence suggesting that reptiles have more complex inner worlds than previously thought. While reptiles have long been known for their cognitive abilities, including problem-solving and learning, this study provides the first clear evidence that they also experience long-term mood states, a key component of sentience.

Understanding whether animals can experience moods and emotions is crucial for informing welfare standards. In the U.K., the Animal Welfare (Sentience) Act 2022 recognizes the capacity of animals to feel, which directly influences how they are treated under the law.

Anna Wilkinson, professor of animal cognition at the University of Lincoln, explained, "Animal welfare concerns are reliant upon evidence that a given species has the capacity to experience affective states. With reptiles becoming increasingly common as pets, it is essential for us to study their moods and emotions to try to understand how captivity may impact them."

Oliver Burman, professor of animal behavior and welfare at the University of Lincoln, added, "This is an exciting finding that represents a significant shift in our understanding of what reptiles can experience, with important implications for how we care for these animals in captivity and interact with them in the wild."

The findings also offer new insights into the evolution of affective states, i.e., emotions and moods, across species. If reptiles, a group that diverged from mammals and birds hundreds of millions of years ago, can experience moods, it suggests that affective states may be more widespread in the animal kingdom than previously believed.