Temperature, Water, and Respiratory Regimes of an Amphibious Snail, Pomacea Urceus (Müller), from the Venezuelan Savannah

Document Type


Publication Date


Publication Source

The Biological bulletin


1. It has been demonstrated that adult snails generally regulate their body temperature below 41° C under experimental conditions and that their upper lethal temperature is between 40 and 45° C.

2. Field data indicate that under natural conditions adult body heat is transfered to the ground of the aestivation burrow by conduction and that this heat is at least in part dissipated by evaporative loss of soil moisture.

3. Under experimental conditions snails can survive for an aestivation period of four times the normal length and with a loss of 62% of their tissue weight. This level of experimental water loss would be inadequate as the only agent of temperature regulation under field conditions but could be a supplement to heat transfer to both soil and air as well as evaporative cooling afforded by the ground.

4. Aestivating adults can survive many days of direct exposure to the tropical sun (out of burrow) while juveniles are dead within two hours or less.

5. The metabolism of aestivation is aerobic with oxygen consumption about one fifth that of active snails.

6. Females provide protection from high temperatures and from water loss for eggs and spat during the dry season. The adaptiveness of superficial aestivation burrows is discussed in relation to the needs of aerobic metabolism for adults and developing eggs.


ISSN: 0006-3185; E-ISSN: 1939-8697


University of Chicago Press



Peer Reviewed