Physiological thermoregulation of mature alligators

https://doi.org/10.1016/0300-9629(84)90033-1Get rights and content

Abstract

  • 1.

    1. A 67.1 kg alligator (Alligator mississippiensis), tested in air, heated twice as fast as it cooled. The cooling thermal time constant was 425 min while alive. Warming and cooling thermal time constants were 421 min after death. The thermal time constant was not appropriate in describing warming in air of mature alligators.

  • 2.

    2. Surface and subdermal heat flow measurements of the 67.1 kg animal indicate greater blood flow in the skin during warming compared to cooling.

  • 3.

    3. Two mature alligators, 49.9 and 103 kg, were heated and cooled in water. Warming time constants were 67 and 116 min respectively. Cooling time constants were 180 and 246 min.

  • 4.

    4. Data from this study were combined with previously published thermal time constants for alligators providing regression equations for alligators ranging from 37 g to 103 kg. Regression equations for alligators tested in water are : τw= 8.81 M0.50τc=12.6 M0.62. Time constants (τ) are in minutes (w = warming, c = cooling) with all measurements in stirred water ; mass, M, is in kg.

  • 5.

    5. Thermal conductance and metabolism data are combined to provide an estimate of the amount the body temperature of theoretical alligators ranging from 50 g to 1000 kg would be elevated by metabolism. A body temperature of 34.2°C is predicted for a 1000 kg theoretical alligator in 30°C water.

References (25)

  • F.H Pough et al.

    A physical basis for head/body temperature differences in reptiles

    Comp. Biochem. Physiol.

    (1976)
  • S.L Robertson et al.

    Thermal conductance and its relation to thermal time constants

    J. therm. Biol.

    (1981)
  • S.L Robertson et al.

    Thermal indications of cutaneous blood flow in the American alligator

    Comp. Biochem. Physiol.

    (1979)
  • L.A Baker et al.

    Temperature induced peripheral blood flow changes in lizards

    J. comp. Physiol.

    (1972)
  • G.A Bartholomew et al.

    Control of changes in body temperature, metabolism, and circulation by the agamid lizard, Amphibolurus barbatus

    Physiol. Zool.

    (1963)
  • G.A Bartholomew et al.

    Size, body temperature, thermal conductance, oxygen consumption, and heart rate in Australian varanid lizards

    Physiol. Zool.

    (1965)
  • G.A Bartholomew et al.

    Oxygen consumption, thermal conductance, and heart rate in the Australian skink, Tiliqua scincoides

    Copeia

    (1965)
  • G.C Grigg et al.

    The role of the cardiovascular system in thermoregulation of Crocodylus johnstoni

    Physiol. Zool.

    (1976)
  • C.R Johnson et al.

    Thermoregulation in crocodilians—III. Thermal preferenda, voluntary maxima, and heating and cooling rates in the American alligator, Alligator mississippiensis

    Zool. J. Linn. Soc.

    (1978)
  • J.W Lang

    Thermoregulatory behavior in adult American alligators

    Am. Zool.

    (1975)
  • J.W Lang

    Amphibious behavior of Alligator mississippiensis: Roles of circadian rhythm and light

    Science

    (1976)
  • K.R Morgareidge et al.

    Cutaneous vascular changes during heating and cooling in the Galapagos marine iguana.

    Nature, Lond.

    (1969)
  • Cited by (14)

    • On the transient temperatures of ectotherms

      1987, Journal of Thermal Biology
    View all citing articles on Scopus
    View full text