A spider falls under the classification of arachnid and are there for cold blooded. The spider uses the thermoregulation system of Poikilothermy, as its body temperature rises and falls with their environment.
The term cold blooded refers to the way in which the bodily temperature changes with the environment. There are three main areas of thermoregulation under the umbrella term cold bloodedness.
- Ectothermy - this refers to creatures that control their temperatures by external means, such as the sun, flowing air or water.
- Poikilothermy - this refers to the creatures who's body temperature rises and falls with the surrounding environment. These creatures would be cold in cold areas and hot in hot ones, changing as they move between them.
- Bradymetabolism - this refers to creatures who have a high active metabolism and a low resting metabolism. These creatures can undergo dramatic changes in their metabolic rate, depending on food availability and temperature. This allows creatures, such as those who live in the desert, able to shut down their body's and approach a near death sate, to survive harsh desert winters, until favourable conditions return.
Only a few creatures fall into all three categories, or use more than one method to control their body temperature. Most creatures rely on one type of thermoregulation to survive, such as snake and lizards lying on rocks, or insect vibrating their muscles in one place to keep warm.
It was originally thought that cold blooded creatures were incapable of controlling their bodily temperatures. It is now known that this is not the case and the term is therefore outdated in scientific content today.