Temperature Management

primary source of heat for ectotherms

solar radiation

formula for solar radiation absorbed

Q_abs = S _* E _* a

“S” in Q_abs = S _* E _* a

solar intensity (^watts/_m²)

“E” in Q_abs = S _* E _* a

exposed surface area in m² (A _* vf_s)

a = area of animal

vf_s = view factor, or % of area exposed to solar radiation

“a” in Q_abs = S _* E _* a

absorptivity (%S absorbed per E)

how herps alter S (solar intensity)

timing of daily activity, location in environment

how herps alter E (exposed surface area)

change shape (area), change orientation (proportion exposed)

how herps alter a (absorptivity)

change color (dark absorbs more than light), change skin guanine orientation (Hyperoliid frog, increases reflectivity)

“R” in Energy Gained = Q_abs ± M ± R ± C ± LE ± G

infrared radiative exchange

variables of infrared radiative exchange

difference in object temperatures, area exposed, infrared emissivity, texture

effect of smooth ventral scales

low infrared radiative exchange rate, reflective

effect of matte dorsal scales

high infrared radiative exchange rate

“C” in Energy Gained = Q_abs ± M ± R ± C ± LE ± G

convective exchange

variables that affect convective exchange

difference in object temperatures, area exposed, convective coefficient (wind speed, size of animal parallel to wind)

how herps manage convective exchange

climb into a tree or bush to increase air flow and cool down

“LE” in Energy Gained = Q_abs ± M ± R ± C ± LE ± G

evaporative cooling

method of evaporative cooling for amphibians

through their skin

method of evaporative cooling for reptiles

panting, gaping, cloacal mucosa

“M” in Energy Gained = Q_abs ± M ± R ± C ± LE ± G

metabolic heat production

type of herps who use metabolic heat production

large reptiles

metabolic heat production in leatherback sea turtles

produce heat by muscle movement (swimming), countercurrent heat exchange in limbs, adipose tissue in head and neck

thermogenesis

produce heat by muscle movement (shivering) to keep eggs warm - metabolic heat production

herps who use thermogenesis

Pythonidae

“G” in Energy Gained = Q_abs ± M ± R ± C ± LE ± G

conduction

conduction definition

transfer of heat between item and a solid (contact)

terrestrial conduction behaviors

snakes moving onto warm roads at night, desert lizards switching between feet to avoid getting too hot

aquatic conduction behaviors

migration among thermoclines/microhabitat

types of thermoregulation

heliotherms, thigmotherms, kleptotherms, thermoconformers

heliotherms

primarily rely on the sun for raising temperature

example of a heliotherm

canyon treefrogs stay on boulders too hot for their predators

thigmotherms

gain heat primarily through conductance

kleptotherms

gain heat from others

kleptothermy examples

sea snakes and tuatara burrow with sea birds, male garter snakes mimic females to get warm from other males

thermoconformers

don’t maintain difference from environment