Differences between wild and captive wolves raise questions
about “normal” health
By Jim Barlow
Gray wolves roaming wild along Alaska’s Yukon River have bigger hearts
than their zoo-bound cousins in Minnesota, and some of the wild wolves
carry an enzyme previously found only in dogs—which raises questions about
their overall health, researchers say.
These factors could be important components of a long-sought biological
equation that defines normal health parameters of animal populations, says
Dr. Peter Constable, associate professor and chief of the food animal medicine
and surgery section in veterinary clinical medicine.
comparing animals in zoos and wild populations to diagnose disease or prove
their health, a biologist has to do certain things, such as physical exams
and blood tests,” says Dr. Constable. “Then you have to compare their findings
to a normal population. The real dilemma is, what is normal? Is it the
zoo population or a wild population? Which values are accurate?”
The studies compared wolves that have lived sedentary lifestyles in
captivity for two or more years in Minnesota and 11 free-ranging wolves
in east central Alaska. The Alaskan wolves traveled an average of some
40 miles daily, including one overnight roam of 80 miles, during the observation-and-capture
Electrocardiograph exams on the populations revealed that the wild wolves
had hearts up to 2!s times the size of those in Minnesota’s zoo wolves.
Such differences are much larger than those reported between Alaskan sled
dogs and inactive dogs.
Three of the 11 wild wolves, but none of the captive wolves, carried
a slow-developing liver enzyme called corticosteroid-induced alkaline phosphatase,
which reflects long-term stress and indicates the presence of hepatic disease.
Dr. Walter E. Hoffmann, professor of clinical pathology, had previously
discovered the enzyme in dogs, and it was believed to be unique to them.
Dr. Charles E. Wiedmeyer, doctoral student in veterinary pathobiology,
is studying the molecular qualities and mechanisms of the enzyme.
Dr. Ken Hinchcliff of Ohio State University also worked on the study,
which was funded by an Ohio State zoo-research program. Findings have been
published in the Journal of Zoo and Wildlife Medicine and Comparative Biochemistry