Re: Does sharks have constant temperature?

Most sharks and fish are poikilotherms, meaning that their bodies are kept 
at the same temperature as their environment.  So if they are in colder 
waters, their bodies will be that cold.  If they are in warmer waters, 
their bodies will be that much warmer.  This is because their vascular 
systems are designed so that much of the heat their bodies generate through 
action is lost to their environment.  So in the case of most sharks, the 
answer to your question is no, their temperature is not constant because 
their environmental temperature is always changing.  However, there are 
some sharks, such as the mackeral shark, whose vascular systems are 
designed to keep much of the heat generated by their bodes, so they can get 
quite hot at times.  But even in those extreme cases, their temperatures 
are not constant because their temperature depends on their activity level.  
I hope this helps!