Tegu Lizard Temperature
Can tegu lizards maintain an elevated body temperature during their reproductive season?
Experiment:
Dr. Glenn Tattersall and a team of researchers in Rio Claro, Brazil studied changes in the heart rate and body temperature of tegu lizards (Salvator merianae), by implanting lizards bred in captivity with specialized electronic chips. One group of lizard lived in an entirely outdoor environment for one year. Three other groups that were subjected to alternating indoor and outdoor environments over the course of three reproductive seasons. These last three groups were also subject to varying ambient temperature, amounts of light, and amounts time spent in and out of doors.
Result:
For most of the year tegu lizards retained a body temperature
between 1 and 1.5 ̊C above ambient temperature. During the reproductive season (October) tegu lizards maintained a body temperature between 4 and 10 ̊C above ambient temperature.
Conclusion:
Tegu lizards increase their body temperature during the reproductive season via more efficient heat conservation, alternation of blood flow, and increased thermal conductance. This increase in temperature may be due to growth of secondary sex characteristics.
Source:
G. J. Tattersall, et al, Seasonal reproductive endothermy in tegu lizards. Science Advances, 2(1): e1500951. doi: 10.1126/sciadv.1500951. (2016).
What If:
What would be some advantages of having an increased body temperature during the reproductive season?
Justification:
While most ectotherms are incapable of maintaining a body temperature above ambient temperature, tegu lizards are one of the rare exceptions. The way this species has evolved is an interesting example the varied ways in which organisms adapt to their specific environments. Little is known as to why tegu lizards increase their body temperature during their reproductive season, making this case excellent for discussion. Students can use this case to apply what they have learned in lectures about animal behaviour. For instance, pupils can practice coming up with proximate and ultimate causations, as well as weighing the costs and benefits of this behaviour. This experiment is also a practical example of how researchers study the behaviour of living organisms.
Experiment:
Dr. Glenn Tattersall and a team of researchers in Rio Claro, Brazil studied changes in the heart rate and body temperature of tegu lizards (Salvator merianae), by implanting lizards bred in captivity with specialized electronic chips. One group of lizard lived in an entirely outdoor environment for one year. Three other groups that were subjected to alternating indoor and outdoor environments over the course of three reproductive seasons. These last three groups were also subject to varying ambient temperature, amounts of light, and amounts time spent in and out of doors.
Result:
For most of the year tegu lizards retained a body temperature
between 1 and 1.5 ̊C above ambient temperature. During the reproductive season (October) tegu lizards maintained a body temperature between 4 and 10 ̊C above ambient temperature.
Conclusion:
Tegu lizards increase their body temperature during the reproductive season via more efficient heat conservation, alternation of blood flow, and increased thermal conductance. This increase in temperature may be due to growth of secondary sex characteristics.
Source:
G. J. Tattersall, et al, Seasonal reproductive endothermy in tegu lizards. Science Advances, 2(1): e1500951. doi: 10.1126/sciadv.1500951. (2016).
What If:
What would be some advantages of having an increased body temperature during the reproductive season?
Justification:
While most ectotherms are incapable of maintaining a body temperature above ambient temperature, tegu lizards are one of the rare exceptions. The way this species has evolved is an interesting example the varied ways in which organisms adapt to their specific environments. Little is known as to why tegu lizards increase their body temperature during their reproductive season, making this case excellent for discussion. Students can use this case to apply what they have learned in lectures about animal behaviour. For instance, pupils can practice coming up with proximate and ultimate causations, as well as weighing the costs and benefits of this behaviour. This experiment is also a practical example of how researchers study the behaviour of living organisms.