How much stress do researchers inflict on their study animals? A case study using a scincid lizard, Eulamprus heatwolei

Abstract

SUMMARY Research on live vertebrates is regulated by ethics committees, who prohibit `excessively stressful' procedures. That judgment is based on intuition – a notoriously unreliable criterion when dealing with animals phylogenetically distant from humans. To objectively evaluate the stress imposed by research practices, we measured plasma corticosterone levels in lizards (Eulamprus heatwolei Wells & Wellington, Scincidae). Some procedures (handling and measuring, toe-clipping for identification, exposure to predator scent) did not induce significant increases in corticosterone levels, suggesting that these stimuli generated relatively little stress. However, other stimuli (testing locomotor speed, microchip implantation, blood sampling, an unfamiliar enclosure, tail autotomy, exposure to a heterospecific lizard) were more stressful, with corticosterone levels increasing only transiently in some treatments (<2 h for tail autotomy), but persisting much longer in others (14 days for microchip implantation). Overall, our data suggest that the levels of stress induced by routine laboratory procedures are no greater than those often experienced by lizards in nature; but that intuition provides a poor basis for evaluating the levels of stress induced by research. For example, toe-clipping is often criticized and sometimes banned;but our data suggest that this method is actually less stressful than the technique frequently recommended to replace it on ethical grounds (microchip implantation). Toe-clipping also was less stressful than superficially trivial manipulations such as housing the animal in an unfamiliar enclosure. More generally, we urge researchers to seek objective information on the effects of their activities on research subjects, rather than relying upon subjectivity and anthropomorphism in making these evaluations.

Prevalence of Salmonella in Australian Reptiles

“…Langkilde and Shine (2006) determined that corticosterone levels in southern water skinks that were transferred into novel environments were higher than animals that had been handled and measured, had toes clipped, or had been exposed to predator scent. Some of the reptiles in the Healesville Sanctuary reptile house were rotated through different enclosures, and there was constant rearrangement of cage furnishings.…”

Acute stress hyporesponsive period in nestling Thin-billed prions Pachyptila belcheri

“…Recent studies show that often, our evaluations of stressful methods, based on intuition, can be notoriously unreliable (e.g. Langkilde and Shine 2006), and suggest using the increase in GCs as a more objective marker of physiological stress in vertebrates (e.g. Romero 2004).…”

“…Romero 2004). Using this method, Langkilde and Shine (2006) compared diVerent research procedures used commonly in lizards, and found that some superWcially trivial manipulations such as housing the animal in an unfamiliar enclosure was very stressful for the animal, while a often criticized method (toeclipping) was less stressful than the technique frequently recommended to replace it on ethical grounds (microchip implantation).…”

Photographic identification of individuals of a free‐ranging, small terrestrial vertebrate

“…Capture and handling, often required to apply marking, may also affect normal behavior of an individual, at least in the short‐term (Rodda et al. 1988; Langkilde and Shine 2006). Such impacts are undesirable, particularly for threatened or rare species (Bradfield 2004), but also when the goal of research is to observe natural population processes and behavior with minimal interference.…”