Animal Welfare: Grizzly Bears Really Dig Their Expanded Habitat

As part of the Detroit Zoological Society’s (DZS) commitment to ensuring individual animals experience great welfare, a significant expansion of the grizzly bears’ habitat was undertaken in 2018. The male grizzly bears living at the Detroit Zoo, Mike, Thor and Boo, are brothers who were rescued in Alaska after their mother was killed and the cubs began foraging too close to humans. At approximately one year of age, they were too young to properly care for themselves and the DZS provided them with a safe place to grow up. The bears are now eight years old and weigh approximately 900 pounds.

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The expansion doubled the amount of space for the bears and also increased the number of environmental features in the habitat, including caves and substrates such as grass and mulch. When we make changes that affect the lives of animals, it is important that we understand how those changes impact them. To that end, we collected data the fall prior to construction to obtain a baseline of the bears’ behavior and hormone levels. Observations continued during construction and ended two months after the bears moved back into their renovated home. Zookeepers also filled out surveys and collected fecal samples each day.

We were happy to see that, in general, the construction itself had little impact on the bears. We had the zookeepers keep track of things like appetite and interest in participating in positive reinforcement training, and the bears did not show any changes to these behavioral indicators of welfare. Additionally, their glucocorticoid concentrations did not change during construction, suggesting that the bears did not perceive this to be a stressful time period. We did see some fluctuation in how much time each bear was visible outside, depending on how loud the construction activities were. Only one of the bears, Mike, spent more time inside (and out of sight) when the construction noise reached higher levels. Individual animals, just like people, perceive experiences differently, and therefore may react differently.

When we compared how and where the bears spent their time before and after the expansion, we had some interesting results. The bears made use of all of the substrates and features in the expanded habitat. They were very excited to gain access to a mulberry tree that had previously been part of one of the side bear habitats. Mulberry is enjoyed by many species at the Detroit Zoo and the grizzly bears are no exception. Mike very industriously spent time trying to uproot the tree to make it easier to eat all the delicious berries! All three bears also enjoyed digging up, excavating if you will, various sections of the habitat. One thing that did not change was Thor’s affinity for his rock “pillow”. There is a large boulder-sized rock formation high up in the original habitat space on which you can sometimes find him resting his head. Thor still very much enjoys giving the rock a bear hug as he catches up on some sleep!

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Not only did the expansion mean the bears had more environmental choices, but the additional features had an impact on their social dynamics as well. With more space and more options within that space, the bears could spread out and all spend time in areas that met their needs, rather than sharing, or having to wait to use the features. This also translated into even more positive relationships between the brothers. We did see Boo practice his best “little brother” moves in the expanded habitat. He will come as close to Mike as possible until Mike finally swats or chases him away. I definitely experienced that with both of my little brothers growing up! It is possible that with more space, Boo enjoys getting a reaction from Mike and having plenty of room for the game of “catch me if you can” that may follow.

The expanded space has given the grizzly bears more behavioral opportunities and the ability to make more choices about how and where to spend their time, as well as how much of that time they want to spend near one another. The DZS is always striving to create habitats that promote great welfare and increased choice is an important part of that.

– Dr. Stephanie Allard is the director of animal welfare for the Detroit Zoological Society and oversees the Center for Zoo and Aquarium Animal Welfare and Ethics.

 

Animal Welfare: More than the “Bear” Necessities

The Detroit Zoological Society (DZS) recently renovated the grizzly bear habitat at the Detroit Zoo, doubling the amount of outdoor and indoor space available to the three rescued brothers. Staff with the Center for Zoo and Aquarium Animal Welfare and Ethics are measuring changes in the bears’ activity budgets, behavioral diversity and fecal glucocorticoid concentrations to assess the impact of the expanded habitat. We will also be testing the efficacy of a biomarker of oxidative stress as a novel indicator of animal welfare.

The grizzly bears living at the Detroit Zoo, Mike, Thor and Boo, are brothers who were rescued in Alaska after their mother was killed by a poacher and the cubs began foraging too close to humans. At just a year old, they were too young to care for themselves and the DZS has been able to provide them with a safe place to grow up. The bears are now 7 years old and weigh approximately 900 pounds. With their inquisitive nature and significant strength, they frequently “redecorate” their habitat by moving logs around and digging in various locations. It became clear that they were outgrowing the habitat they called home since 2012.

As part of the DZS’s commitment to ensuring individual animals experience great welfare, a significant expansion of the grizzly bears’ habitat is underway. Not only will this augment the amount of land space available to the bears, it will also provide them with new behavioral choices. They will have access to more features such as caves to provide cool, shaded areas. The larger habitat will also increase natural foraging opportunities for the bears.

When we make changes that affect the lives of animals, it is important that we understand how those changes impact them. To that end, we began collecting data last fall, prior to construction, to obtain a baseline of the bears’ behavior and hormone levels. Observations continued during construction and will end two months after the bears move back into their renovated home. Zookeepers have also been filling out daily surveys to add to the information we are gathering. Fecal samples are collected daily and these will be analyzed in our lab to measure hormone levels related to how the bears react to these changes. Using these different types of data in concert will increase our understanding of the expansion effect on the bears’ overall well-being.

Dr. Stephanie Allard is the director of animal welfare for the Detroit Zoological Society and oversees the Center for Zoo and Aquarium Animal Welfare and Ethics.

Notes from the Field: Polar Bears in Alaska

Greetings from zip code 99747 in Kaktovik, Alaska!

Kaktovik lies on the far northeast coast of Alaska above the Arctic Circle and in the Arctic National Wildlife Refuge (ANWR). It is a whaling community with a long history of its people living in close proximity to polar bears. I traveled to Kaktovik in 2014 and again in 2015. This time I am fortunate to be joined by one of the Detroit Zoological Society’s (DZS) associate mammal curators, Betsie Meister, who has extensive experience with polar bears and oversees the Arctic Ring of Life, an expansive 4-acre habitat at the Detroit Zoo that is home to polar bears, seals and arctic foxes.

We are here to help colleagues with U.S. Geological Survey, U.S. Fish and Wildlife Service and ANWR to study changes in polar bear numbers, as well as polar bear behavior and use of resources in response to the changing climate. As the climate warms, the arctic summer is getting longer and sea ice is diminishing. Polar bears come off the sea ice usually in late August and spend September and a few weeks of October in the area around Kaktovik waiting for the sea ice to form again. Polar bears use the sea ice as their platform for hunting seals, which is the majority of their wild diet. Without access to the ice, the bears are forced to spend more time on land.

The Inupiat community of Kaktovik hunt bowhead whales every fall to store enough food for the winter. After processing the whales on the beach, the whale remains are taken about a mile and half to the edge of town and placed in the “bone pile”. Polar bears come to feast on the remains, which continue to be a strong attractant for weeks. Kaktovik, which is home to approximately 300 people year round, adds a population of polar bears numbering 15-40 and up to 80 in the late summer and fall. As a result, Kaktovik is becoming more and more popular with tourists from all over the world coming to see the polar bears.

The bears primarily stay on the barrier islands just outside of town, but there is a great potential for human-bear conflict, and the DZS is interested in seeing how Kaktovik handles the conflict. Usually, the bears are kept away with all-terrain vehicles (ATVs) and trucks, but sometimes more force is necessary. Shotguns loaded with “cracker shells” or bean bags are then used to keep the bears away. An important safety measure that has been established is the Polar Bear Patrol. This patrol drives around Kaktovik every night from 8 p.m. to 8 a.m. protecting the community from bears wandering into town. This year, there was more whale meat at the bone pile than last year, so bears seemed to stay near the pile and away from town. Last year, while I was in Kaktovik, an incident occurred when a bear consumed some dog food from underneath the house next to ours and entered another house to feed on seal blubber.

We came to Kaktovik a week earlier than last year hoping to also observe brown bears. Brown bears have also been affected by the warming climate. They are moving farther north and coming into more contact with polar bears, overlapping more in resource use and, in some places, even hybridizing with polar bears. At Kaktovik, both bear species have been observed feeding on the whale remains, and the DZS is interested in better understanding the overlap in resource use between these species. Unfortunately, no brown bears were seen this year during our time in Kaktovik, and locals informed us that only two or three brown bears had been seen this year.

Kaktovik is just one of the communities on Alaska’s North Slope that face unique circumstances with our Earth’s changing climate. The increased interaction with polar bears and brown bears is a fascinating situation and will become increasingly important for the management of both species. With continued monitoring of bears on the North Slope, the safety of both the public and the bears will remain the top priority of the community, and the DZS will assist in this effort.

– Paul Buzzard, Ph.D., is the director of conservation for the Detroit Zoological Society and Betsie Meister is the associate curator of mammals.