Ask a Shark Expert
Read shark researcher Mark Marks' responses on the following shark topics:
Disappearing sharks
Shark evolution
Shark deterrent?
Nonstop swimmers?
Shark posturing
Swimming with the sharks?
Shark diving
Shark education
Shark enemies
Shark reproduction
Great white disposition
Favorite shark
Shark eyes
Shark companions
Bite pressure
Bladderless sharks
Warmblooded killers
Hammerheads
Thresher sharks
Great whites in captivity
Shark protection
Q: On Warmblooded Killers Isn't it true that (I believe mainly due to their size) great whites are warmblooded ? Also, aren't they (great whites) killed by orcas ?
Michael Tennant
A: The white shark is known as "point endothermic." This means that white sharks and their immediate relatives are warmblooded-like, not truly warmblooded in the same way that mammals are, but with a similar result. White sharks possess a counter heat-exchanging system within their circulatory system. These heat exchangers, called the "rete mirabile," are bundles of tiny blood capillaries surrounded by muscles assisting to resist heat loss during circulation and respiration. Warmbloodedness allows these sharks to travel over great distances and not be regulated in their movements by a change in water temperature. In addition, it provides the shark with a metabolic "on demand" afterburner for quick acceleration. Essentially, the muscles are always warmed up when the shark needs to kick in speed. And you are right, other than humans, orcas appear to be the only natural predators of adult white sharks.
