The Minnesota Zoo is known for its innovative exhibits, which include some of the best displays of temperate and subarctic fauna anywhere in the world. Recently, the Zoo has borrowed some husbandry techniques from the livestock industry to help care for moose, a species so hard to manage in captivity that very few zoological institutions have even attempted to care for them.
Unless you have been fortunate enough to travel to northern latitudes of North America and Eurasia, the probability of ever viewing a live moose is quite rare. Although, moose can be frequently encountered in the wild, as they are up here in Alaska, they are not at all common in zoos. In fact, when you consider all of the charismatic megafauna that are commonly displayed in captive wildlife facilities, the one species that is markedly absent is the moose.
Zoophile or not, has it ever occurred to you why the moose, the largest cervid (deer) on Earth is rarely seen in captivity?
Until recently, modern day zoological parks have had great difficulty raising and managing moose in captivity outside of their natural range, where access to natural forage is precluded by the location of the particular zoo. Captive moose reared at the few zoos in the lower 48 that have attempted to house them, often succumbed to enteritis and a chronic wasting condition. Even in the early to late 90’s moose calves would rarely make it to adulthood. While other cervids like white-tailed deer and mule deer typically survive 15-20 years in captivity, moose, which should live just as long without natural predators, tended to die prematurely. The animals simply could not be sustained on a diet of alfalfa hay, grass, and grain like other deer species do in zoological facilities.
Although some animals do succumb to chronic wasting, new commercial diets have made it possible to rear moose outside of their natural range.
Another concern is thermoregulation. Adult moose have low surface-area-to-volume ratio, placing constraints on their heat dissipation capacities. They are remarkably sensitive to ambient temperatures that we as humans and other animals consider quite comfortable. For example, temperatures as low as 57 degrees F can begin to induce heat stress. At 68 degrees moose begin to ventilate by noticeably panting.
To prevent the induction of heat stress, the Minnesota Zoo has installed Dual Chamber Cow (DCC) Waterbeds in two of the Zoo’s five holding stalls for moose to help promote heat loss in these highly heat-sensitive ungulates. The water beds were donated by Advanced Comfort Technology, Inc., a Wisconsin-based company.
Donated as part of a zoo-led research study on heat stress, DCC waterbeds were customized to fit the elongated bodies of the moose. The moose are rotated through the holding area stalls daily as part of their regular routine, but also so researchers can collect thermoregulatory data while the moose are on the waterbed and the conventional rubber mat.
“Moose are traditionally bedded on rubber mats topped with straw in the zoo holding area,” said Dr. Nick McCann, Minnesota Zoo conservation biologist and author of the heat stress study. “The rubber mats may be insulating the moose – they may not allow heat to be conducted away from their bodies to the ground below. One of the questions we will ask in this study is whether the waterbed will be better than the rubber mat at conducting the heat because water is an excellent conductor of heat.”
Just as other animals like apes and bears are brought into holding areas on a daily basis so that keepers can access the exhibits and tend to other duties, exotic hoof stock, much like certain domestic and alternative livestock, are brought into barns at captive wildlife facilities where individuals can be catered to in their own stalls.
“When they are in the holding area, we are trying to make them as comfortable as possible,” said McCann. The four moose are placed in the holding area so that the zookeeping staff can monitor their health and behavior, feed them, and ensure nighttime security. Keeping them cool is key to helping keep them comfortable.
“With more than a decade of superior cow-comfort performance in dairy barns around the world, we are certain that the Minnesota Zoo moose will be comfortable on DCC Waterbeds,” said Dean Throndsen, president and CEO of ACT, Inc. “And for years farmers have told us that DCC Waterbeds stay cool in the summer as they absorb the cool temperatures of the concrete they are anchored to, as well as pull heat off the cows. It is exciting for us to have a researcher, not only studying DCC Waterbeds in this new and interesting setting, but also analyzing their cooling properties in a scientific study.”
The Zoo’s Communication Staff said, “The overall objective of the study is to determine how the ambient air temperature, the bedding surface, humidity, solar radiation, and other factors combined signal to the moose that it is “hot.” Researchers are will compare how hot moose are when bedded on the waterbed surface and the rubber mats. Preliminary results of the study will be ready this winter.”