Diving Biology of Emperor Penguins

Venous and abdominal temperatures were recorded in free-diving emperor
penguins in order to evaluate the hypothesis that hypothermia extends
the duration of aerobic diving. Although anterior abdominal
temperatures gradually decreased during diving, core temperature
(inferior vena cava temperature) remained stable. No evidence was
found to support the hypothesis of hypothermic extension of aerobic
diving. Rather, findings were consistent with conservation of core
temperature, peripheral vasoconstriction, and cooling of an outer
peripheral body shell.

In addition, diving behavior of emperors was examined with the use of
National Geographic's Crittercam camera, a remote underwater camera
unit attached to the diving bird. This established that the birds
routinely feed on the sub-ice fish, Pagothenia borchgrevinki.