Browsing by Subject "thermoregulation"
Now showing 1 - 3 of 3
- Results Per Page
- Sort Options
Item Open Access Body temperature and thermal environment in a generalized arboreal anthropoid, wild mantled howling monkeys (Alouatta palliata).(Am J Phys Anthropol, 2014-05) Thompson, Cynthia L; Williams, Susan H; Glander, Kenneth E; Teaford, Mark F; Vinyard, Christopher JFree-ranging primates are confronted with the challenge of maintaining an optimal range of body temperatures within a thermally dynamic environment that changes daily, seasonally, and annually. While many laboratory studies have been conducted on primate thermoregulation, we know comparatively little about the thermal pressures primates face in their natural, evolutionarily relevant environment. Such knowledge is critical to understanding the evolution of thermal adaptations in primates and for comparative evaluation of humans' unique thermal adaptations. We examined temperature and thermal environment in free-ranging, mantled howling monkeys (Alouatta palliata) in a tropical dry forest in Guanacaste, Costa Rica. We recorded subcutaneous (Tsc ) and near-animal ambient temperatures (Ta ) from 11 animals over 1586.5 sample hours during wet and dry seasons. Howlers displayed considerable variation in Tsc , which was largely attributable to circadian effects. Despite significant seasonal changes in the ambient thermal environment, howlers showed relatively little evidence for seasonal changes in Tsc . Howlers experienced warm thermal conditions which led to body cooling relative to the environment, and plateaus in Tsc at increasingly warm Ta . They also frequently faced cool thermal conditions (Ta < Tsc ) in which Tsc was markedly elevated compared with Ta . These data add to a growing body of evidence that non-human primates have more labile body temperatures than humans. Our data additionally support a hypothesis that, despite inhabiting a dry tropical environment, howling monkeys experience both warm and cool thermal pressures. This suggests that thermal challenges may be more prevalent for primates than previously thought, even for species living in nonextreme thermal environments.Item Open Access Evaluation of Thermal Characteristics of Secondary Warm-Water Sites for the Florida Manatee(2010-04-30T19:05:50Z) Loomis, Caroline PittWhile the threat of collisions with recreational watercraft continues to be a serious concern for the Florida manatee population, a growing threat in the future is likely to be the loss of available winter habitat. Manatees are at risk of illness or death in water temperatures less than 20°C. To meet their thermoregulatory needs, manatees rely on sources of warm-water habitat. Currently the majority of the population is utilizing thermal discharges at coastal power plants to stay warm during winter cold periods; however, most of these power plants are expected to close down in the next t20 to 50 years. Since 1998 the Florida Fish and Wildlife Conservation Commission (FWC) has collected time-series temperature data at various sites used by manatees in winter. The goal of my project was to evaluate the thermal characteristics of 10 suspected warm-water sites in southern Florida to assess their potential suitability as winter habitat for manatees. Sites were assessed based on how frequently they were at temperatures considered threatening to manatee health and mortality, and on how many consecutive days they remained below these threshold temperatures. Delta-T and regression analysis were also used to compare the temperature of potential warm-water sites to that of nearby ambient sites. The results of this analysis will be used to make recommendations to the FWC about which sites might provide suitable warm-water habitat and should be further investigated with more detailed monitoring efforts in the future. This information could be used to meet the agency’s long-term goal of creating a protected network of warm-water habitat throughout the state.Item Open Access Thyroid hormone fluctuations indicate a thermoregulatory function in both a tropical (Alouatta palliata) and seasonally cold-habitat (Macaca fuscata) primate.(Am J Primatol, 2017-11) Thompson, Cynthia L; Powell, Brianna L; Williams, Susan H; Hanya, Goro; Glander, Kenneth E; Vinyard, Christopher JThyroid hormones boost animals' basal metabolic rate and represent an important thermoregulatory pathway for mammals that face cold temperatures. Whereas the cold thermal pressures experienced by primates in seasonal habitats at high latitudes and elevations are often apparent, tropical habitats also display distinct wet and dry seasons with modest changes in thermal environment. We assessed seasonal and temperature-related changes in thyroid hormone levels for two primate species in disparate thermal environments, tropical mantled howlers (Alouatta palliata), and seasonally cold-habitat Japanese macaques (Macaca fuscata). We collected urine and feces from animals and used ELISA to quantify levels of the thyroid hormone triiodothyronine (fT3). For both species, fT3levels were significantly higher during the cooler season (wet/winter), consistent with a thermoregulatory role. Likewise, both species displayed greater temperature deficits (i.e., the degree to which animals warm their body temperature relative to ambient) during the cooler season, indicating greater thermoregulatory pressures during this time. Independently of season, Japanese macaques displayed increasing fT3levels with decreasing recently experienced maximum temperatures, but no relationship between fT3and recently experienced minimum temperatures. Howlers increased fT3levels as recently experienced minimum temperatures decreased, although demonstrated the opposite relationship with maximum temperatures. This may reflect natural thermal variation in howlers' habitat: wet seasons had cooler minimum and mean temperatures than the dry season, but similar maximum temperatures. Overall, our findings support the hypothesis that both tropical howlers and seasonally cold-habitat Japanese macaques utilize thyroid hormones as a mechanism to boost metabolism in response to thermoregulatory pressures. This implies that cool thermal pressures faced by tropical primates are sufficient to invoke an energetically costly and relatively longer-term thermoregulatory pathway. The well-established relationship between thyroid hormones and energetics suggests that the seasonal hormonal changes we observed could influence many commonly studied behaviors including food choice, range use, and activity patterns.