Hyperthermia in Captured Impala (Aepyceros Melampus): A Fright Not Flight Response

Abstract

To investigate the patterns and mechanisms of capture-induced hyperthermia, we surgically implanted 26 impala (Aepyceros melampus) with miniature thermometric data loggers, which measured body temperatures continuously throughout capture procedures. Four groups of impala, which were habituated to varying levels of handling and boma-housing, were captured by net restraint or by chemical immobilization. The study took place between July 1999 and December 2005. Irrespective of whether impala were chemically captured, net-captured, or disturbed by exposure to a stressor, they developed a precipitous increase in body temperature. This increase in body temperature was not related to activity levels; animals that had low activity levels before immobilization had larger increases in body temperature compared to those that had high activity levels but were not immobilized (t = 3.6, P = 0.001, n = 5). Similarly this increase in body temperature was not related to environmental heat load at the time of darting and immobilization (r = -0.05, P = 0.85). Body temperature increase also did not depend on whether the animals were captured using drugs or not. However, we found that those animals that were habituated more to handling and boma-housing had smaller increases in body temperatures (F = 37, P<0.001) and smaller stress responses, indicated by lower plasma cortisol concentrations (F = 5.5, P<0.05), and less fractious behavior, compared to those animals that were habituated less or not at all. Therefore we believe that capture-induced hyperthermia in impala is caused predominantly by stress, which induces a rapid rise in body temperature.

Microchip transponder thermometry for monitoring core body temperature of antelope during capture

“…1), followed by a slow resolution of the hyperthermia to normothermy, a pattern similar to that seen when springbok were captured from the wild (Fuller et al, 2005). The precipitous rise in abdominal temperature of our springbok also was similar to that observed during capture and immobilization of other medium-sized African antelope such as impala (Aepyceros melampus; Meyer et al, 2008) and blesbok (Damaliscus dorcas; Sawicka et al, 2015). Water dousing rapidly and effectively decreased abdominal temperature ( Fig.…”

“…Capture of wildlife for translocation, veterinary procedures, or research, which is crucial for wildlife conservation and management, induces severe hyperthermia in animals (Kock et al, 2006;Meyer et al, 2008). Capture-induced hyperthermia, which results primarily from stress or fear, and can be exacerbated by physical exertion (Meyer et al, 2010), is believed to be the predominant cause of morbidity and mortality when wildlife is captured (Williams & Thorne 1996, Kock et al, 2006.…”

Minimum daily core body temperature in western grey kangaroos decreases as summer advances: a seasonal pattern, or a direct response to water, heat or energy supply?

“…These increases may have been due to exercise activity, although they all occurred during the normal rest phase. It is possible that the episodes were stress hyperthermia, in the absence of intense exercise, as has been reported for impala (Meyer et al, 2008). The episodes occurred twice on days when members of the research team observed the kangaroos, but there were many more days on which the kangaroos were observed when such episodes did not occur.…”

Short-term effects of tagging on activity and movement patterns of Eurasian beavers (Castor fiber)

“…blood parameters and/or faeces; Bosson et al 2012;Harcourt et al 2010;Rehnus et al 2009;Sheriff et al 2011). Indeed, capture effects might only be physiological (Kock et al 1987;Meyer et al 2008) and do not necessarily imply visible behavioural changes. Likely, these effects do not lead to a bias of results in behavioural studies, but do still have implications regarding animal welfare.…”