Thermoregulatory behaviour assessment and thermal imaging of large felids

Date

2016-05-13

Authors

Stryker, Judith A.

Journal Title

Journal ISSN

Volume Title

Publisher

University of Guelph

Abstract

Various species of large felid are kept in zoos in climates that differ from those of their wild range. Until very recently thermal comfort and microclimatic zoo exhibit design has not been at the forefront of zoo habitat designs, as it has in livestock production. Few behavioural studies have been reported for captive exotics in the zoo setting. Thermoregulatory behavioural needs and comfort have been investigated in an observational study of several large felid species housed at Toronto Zoo (Toronto, Ontario, Canada), and Busch Gardens in Tampa, Florida. This study included continuous behaviour observations, in association with meteorological measurements (ambient temperature (°C), relative humidity (%), wind speed (m/s), solar radiation (W/m2), and the presence or absence of precipitation and shadows. Infrared thermal imaging of individual animals, were recorded every 15 minutes. In addition, a pilot study including infrared thermal imaging in conjunction with traditional rectal and axillary thermometer readings was carried out with domestic house cats (Felis catus) as a model to investigate the use of thermography for core body temperature measurement. Eight tigers (Panthera tigris) (n = 5 female, n=3 male), observed during summer, were housed at Busch Gardens, Tampa, Florida. To investigate felid species differences, several species were compared (lions (P. leo) (n=3 male and n=2 female), jaguars (P. onca) (n=1 female and n=1 male), tigers (P. tigris altaica) (n=1 male), cougars (Puma concolor) (n=1 female and n=1 male) and snow leopards (P. uncia) (n=1 male and n=1 female)) at the Toronto Zoo in Ontario, Canada during summer and winter. Descriptive statistics were used to analyze the data. The tigers in Florida spent most of their time inactive lying (>45%) in the shade (>20%) with water as an important cooling zoo habitat resource for some individuals. Through species comparisons in behaviour and enclosure feature use, it was found that large felids could be grouped into two subgroups based on habitat of origin (i.e. hot climate cats and cold climate cats), and that zoo habitats could be designed for thermal comfort of these groups. Amur tigers and snow leopards are examples of cold climate cats, where lions and jaguars are examples of hot climate cats. All these felid species spent most of their time lying (40 - 84%) and relatively little time on active behaviours (5 - 10%). Shade was important for all species in summer (23 – 50% average daily time). Finally, eye surface temperature was closest to rectal and axillary temperatures, indicating that this may be the most appropriate thermography target for core body temperature assessment. The combined results the three studies described above, provide evidence that habitat of origin may play a role in the differences in thermal comfort and neutral zones of various felid species studied, and that zoo exhibit microclimatic landscape design can be informed by thermoregulatory behaviour studies to promote thermal comfort and efficiency in captive felid species.

Description

Keywords

Thermoregulation, Thermoregulatory behaviour, Large felids, Panthera, Thermography, Micrcolimatic landscape design, Natural sciences

Citation