How can we assess anxiety and welfare in reptiles?

Moszuti, S. A., Wilkinson, A., & Burman, O. H. (2017). Response to novelty as an indicator of reptile welfare. Applied Animal Behaviour Science.

This study investigated whether response to novelty can be used as a welfare indicator in reptiles.  It also aimed to identify other behaviours in reptiles that may indicate levels of anxiety.

This study observed the behaviour of eight captive red-footed tortoises and seventeen bearded dragons in familiar and unfamiliar environments.  Response to novelty is often used as an indicator of anxiety and hence welfare in other animals, but this approach has not yet been used for reptiles.  The animals behavior was observed in familiar and unfamiliar enclosures for 10 minute periods.

Red-footed tortoises move less in novel environments

Results found that the tortoises began moving much sooner in the familiar environment than the unfamiliar one. The tortoises also stretched their necks further in the familiar environment. The bearded dragons performed more tongue touching (tongue flicking on a surface) in the novel environment compared to when they were in the familiar environment.

This reluctance to move in an unfamiliar environment has been observed in mammals and birds and can be used as an indicator of anxiety and reduced welfare.  It is shown here that this behaviour may also be used as an indicator of anxiety in red footed tortoises.  Since they also stretch their necks further in the familiar environment, this may also indicate reduced anxiety and may be used to assess their welfare.  They also stretched their necks further with time in both environments, again suggesting that neck stretching may be an indicator of a more relaxed state.  Differences in the rate of tongue touching in bearded dragons suggests that they can distinguish between the two environments, but this does not necessarily correlate with anxiety as they did not show the same reluctance to move in the novel enclosure.

The number of reptiles in captivity in the UK is rising, with many being kept as pets.  Husbandry and housing are often inappropriate, and this is reflected by high numbers of mortalities. Many studies show that mammals and birds alter their behaviour when placed in a stressful environment such as a new enclosure.  For example, reluctance to enter the environment is interpreted to indicate anxiety and reduced welfare, with increasing familiarity resulting in less anxiety.  This study shows that this method of assessing welfare is at least partially transferable to reptiles. The red-footed tortoise behaves similarly in its reluctance to move when faced with novelty although the bearded dragon doesn't. The findings suggest that this can be used to indicate anxiety in the tortoises but perhaps not in the bearded dragon. The research identifies some specific behaviours that can perhaps be used to assess anxiety levels and welfare in the future (neck extension in tortoises and tongue touching in bearded dragons). There are some similarities in how we can assess welfare in different reptiles but there are also likely to be differences.

World Animal Protection’s view

Difficulties in assessing reptile welfare has had implications for captive reptiles, resulting in their needs often not being met.  This study has introduced some potential methods to measure anxiety and compromised welfare, but more work is needed.