A
dolphin, being a mammal, is warm-blooded. It requires a constant body temperature of 96.8 - 98.6 degrees F, almost
the same as ours. Because the dolphin's metabolism is higher than that of land mammals of similar size, it generates a great
deal of heat. In addition, dolphins breathe less frequently than most land mammals so less heat is lost by exhaling into
the environment.
This heat production
must be regulated to keep the animal from over-heating. It can “thermo-regulate”, or control its body temperature
in the following ways: (1) blubber insulates the body against temperature changes, (2) the dorsal fin and flukes release excess
heat from the body, (3) during dives, blood circulation is reduced at the outer portions of the body and concentrated into
the animal's core organs and tissues,(4) body heat is conserved by transferring
it from one blood vessel to another during circulation instead of being released to the environment, and (5) it can move to cooler
or warmer areas within its aquatic environment.
As
has been mentioned earlier, calves are not able to fully thermo-regulate until about three years of age. In addition, calves
do not proportionally increase blubber thickness in colder environments as do adult dolphins. This is likely due to the fact
that a disproportionate increase in blubber thickness in calves would make the animal more buoyant than practical and the
calf would be presented with the difficulty of battling the tendency to float. Blubber is highly vascularized (filled with
blood vessels) which provides it with the ability to keep itself warm by circulating vast amounts of warm blood to its body
surface. There appears to be an upper limit to the blubber thickness-to-body-size ratio set by the locomotor costs associated
with a dolphin's need to overcome buoyancy (recent research from the University of California Santa Cruz, 2002). This may
help to explain how female dolphins respond to their calves' thermo-regulation handicap and why lactating
females show a preference for shallow (warmer) ocean waters for nursing their calves.
Site Content
Understanddolphins.com contains information condensed from a number of reputable technical sources,
peer reviewed journal articles, and respected dolphin research facilities, as well as from my personal experiences and
observations as a dolphin VIP Tour Guide and Educator.
I have made every attempt to support the information presented in this site with video and still
photographic images. On a regular basis I plan to produce more of these images and will continue to update the site with these
as well as with any new and scientifically verified information which becomes available.
