Thermoregulation in the Mouths of Feeding Gray Whales
John E. Heyning,
James G. Mead
Vascular structures for heat conservation in the tongue of the gray
whale (Eschrichtius robustus) are reported here. Numerous individual countercurrent heat exchangers are found throughout the
massive tongue. These converge at the base of the tongue to form a
bilateral pair of retia. Temperature measurements from the oral cavity
of a live gray whale indicate that more heat may be lost through the
blubber layer over the body than through the tongue, despite the fact
that the tongue is far more vascularized and has much less insulation.
These heat exchangers substantially reduce heat loss when these whales
feed in cold waters.
J. E. Heyning, Section of Vertebrates, Natural History
Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA
90007, USA. E-mail: heyning{at}bcf.usc.edu
J. G. Mead, Division of Mammals, National Museum of Natural
History, Washington, DC 20560, USA. E-mail: mead.james{at}nmnh.si.edu
