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. 

“When 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 period.

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 and Physiology.