At a Glance
- Scientists at the University of Lincoln provided compelling new evidence that red-footed tortoises are capable of experiencing long-term, “free-floating” mood states, similar to those found in mammals.
- The research team used a cognitive judgment bias task, which revealed that tortoises housed in appropriate conditions displayed an optimistic mood by approaching ambiguous locations more quickly.
- This optimistic judgment was directly linked to behavior in concurrent anxiety tests, where the same individuals showed significantly less anxious responses when introduced to novel objects and environments.
- These findings have significant implications for animal welfare standards, particularly under legislation such as the UK’s Animal Welfare (Sentience) Act 2022, which legally recognizes animal sentience.
- The discovery also advances our understanding of the evolution of emotion, suggesting that affective states are a more ancient and widespread trait across the animal kingdom than believed.
New research into the minds of reptiles published in Animal Cognition suggests they may have richer inner worlds than previously believed, a finding that could reshape their treatment in captivity. In a pioneering study, scientists at the University of Lincoln have found compelling evidence that red-footed tortoises exhibit long-term, or “free-floating,” moods —a capacity once thought to be limited to animals such as mammals and birds. This discovery challenges long-held assumptions about reptile sentience—the ability to experience subjective feelings and emotions—and carries significant implications for animal welfare standards.
To peer into the tortoises’ state of mind, the research team employed a method known as a cognitive judgment bias task. This test is designed to reveal whether an individual is in an optimistic or pessimistic mood by observing how they judge an ambiguous situation. The 15 tortoises in the study were first trained to associate one location with a food reward and a different location with nothing. Researchers then presented them with new, ambiguous locations between the two. The study found that tortoises approached these uncertain spots more quickly when they were closer to the rewarded location, a sign of optimism suggesting they were in a positive underlying mood.
Separate anxiety tests supported the findings from the bias task. Tortoises that behaved more optimistically by approaching ambiguous locations also showed less anxious behavior, such as hiding, when exposed to new objects and unfamiliar environments. This link reinforces the idea that a consistent mood state drove their decisions. “Animal welfare concerns are reliant upon evidence that a given species can experience affective states,” said Anna Wilkinson, a professor of animal cognition at the University of Lincoln, in a university press release. “With reptiles becoming increasingly common as pets, it is essential for us to study their moods and emotions.”
This research not only has immediate implications for the care of reptiles under laws such as the U.K.’s Animal Welfare (Sentience) Act 2022, but also offers a new window into the history of emotion itself. Since reptiles diverged from the evolutionary paths of mammals and birds hundreds of millions of years ago, the presence of moods in tortoises suggests that these affective states are an ancient and widespread trait across the animal kingdom. “This is an exciting finding that represents a significant shift in our understanding of what reptiles can experience,” added Oliver Burman, a professor of animal behavior and welfare at the university.
References
- Hoehfurtner, T., Wilkinson, A., Moszuti, S. A., & Burman, O. H. P. (2025). Evidence of mood states in reptiles. Animal Cognition, 28(1), 52. https://doi.org/10.1007/s10071-025-01973-y
- McGowan, H. & University of Lincoln. (2025, July 8). New study shows tortoises experience feelings similar to our own. Phys.Org; University of Lincoln. https://phys.org/news/2025-07-tortoises-similar.html
