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The influence of body
temperature on sprint speed and anti-predatory defensive
responses of the North African monitor lizard, Varanus
griseus
A. I. Okafor
Department
of Zoology, Abia State University, Uturu - Nigeria.
E-mail:
tconnection68@yahoo.com.
Accepted 7
October, 2009 |
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The running speed of the North African monitor lizard,
Varanus griseus is directly proportional to its body
temperature of between 21 and 37°C. Above 37°C, sprint speed
does not increase. However, below 21°C, the lizards are
extremely sluggish. If pursued at this lowered body
temperature the animal finds it difficult to escape and so
stays behind and tries to fight the predator. The degree of
aggressiveness increases as body temperature is further
reduced. This monitor lives in the savanna regions of
northern Nigeria where the vegetation is low and hiding
places are rare. The lizard might have evolved this
anti-predatory mechanism at low body temperatures as its
last resort to survive since there is no place to take
refuge in a bare area when the predator emerges.
Key
words:
Body temperature, sprint speed, anti-predatory mechanisms. |
