The interest in the welfare of zoo animals, from both the public and the scientific community, has long been biased towards mammals. However, growing evidence of the complex behavioural repertoires of less charismatic animals, such as reptiles, reveals the necessity to better comply with their welfare needs in captivity. Here, we present the effects of an enclosure change towards a more natural habitat in captive Galapagos tortoises (Chelonoidis spp.) held at ZSL London Zoo. Using behavioural observations, we found that the tortoises habituated to their new enclosure in six days. This represents the first quantification of habituation latency to a new enclosure in a reptile model to our knowledge—which is important information to adapt policies governing animal moves. The tortoises expressed time budgets more similar to those of wild individuals after their transition to the new enclosure. Interestingly, the hierarchy between the individuals was inverted and more stable after this change in environment. The tortoises interacted less often, which led to a decrease in the frequency of agonistic encounters. We also found that higher ambient sound volume was associated with increased likelihood of interactions turning into fights. Taken together, our results demonstrate the potential of appropriate enclosure design to improve reptile welfare.

Visitors to zoos can have positive, neutral, or negative relationships with zoo animals. This makes human–animal interactions (HAIs) an essential component of welfare and an important consideration in species selection for zoo exhibits and in enclosure designs. We measured the effect of visitors on reptiles by comparing open and closed periods during the lockdowns in response to the COVID-19 pandemic in the UK in a low-resolution dataset for thirteen species of reptiles and a high-resolution dataset focussing on just one of these. Scan sampling on thirteen reptile species (two chelonians and eleven squamates) showed species-specific differences in response to the presence/absence of visitors, with most taxa being only weakly affected. High-resolution scan sampling via video footage of an off-show and on-show enclosure was carried out for tokay geckos (Gekko gecko) over the open and closed periods. In this part of the study, tokay geckos were significantly more visible during zoo closure than when visitors were present on-exhibit, but there was no change in off-show animals, indicating the effect of visitors as opposed to other factors, such as seasonality, which applied equally to both on- and off-show animals. The high-resolution study showed that a significant effect was present for tokay geckos, even though the low-resolution suggested that they were more weakly affected than other taxa. Our results indicate that, for cryptic species such as this, more intensive sampling may be required to properly understand visitor effects. Our data do not allow the interpretation of effects on welfare but show that such assessments require a species-specific approach.

Calcium metabolism in insectivores may be perturbed by insufficient calcium or vitamin D₃. Insects may be gut loaded to increase calcium content, and recent research shows that exposure to UVB radiation can increase the vitamin D₃ content of some invertebrates. Typical gut loading protocols result in peak calcium content after 24–48 h, while existing evidence with UVB irradiation involves exposure periods of tens of days. We UVB-irradiated fasted black field crickets (Gryllus bimaculatus) while feeding them on high calcium diets for 48 h, then fasted them for a further 24 h, and measured the vitamin D₃, calcium, and phosphorus content compared with non-irradiated controls. UVB irradiation had no effect on vitamin D₃ (crickets had no detectable levels of vitamin D₃ at any point), or on calcium accumulation rates, which approximated existing research. Crickets significantly increased their calcium:phosphorus ratio from 0.17 to approximately 0.4 over 24 h and this did not increase over a further 24 h of feeding. Removal of the food source resulted in loss of all accumulated calcium within 24 h. Our results have implications for managing food sources for captive insectivores and highlight the importance of good feeder preparation and rapid consumption to ensure optimal calcium delivery to predators.