animal behavior

Animal Welfare: Welfare Assessments

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One of the goals of the Center for Zoo and Aquarium Animal Welfare and Ethics is to conduct and facilitate animal welfare assessments. In some cases, this entails conducting scientific research aimed at answering questions such as how animals respond to changes in their habitats or modifications to the ways in which we care for them.  For example, and as you may have read about in previous blog entries, we assessed the impact of new or expanded habitats on the welfare of Madagascar giant hog-nosed snakes, penguins and grizzly bears at the Detroit Zoo, just to name a few. We also pose questions related to providing animals with stimulating experiences that allow them to engage in species-appropriate behaviors, such as increasing exploration in aardvarks and enhancing natural feeding opportunities for species like seals and gorillas. The more we can learn about how our animal care and management practices influence the welfare of animals, the more we can do to ensure they are thriving.

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Although multi-faceted studies like the ones mentioned above are an important part of this endeavor, developing means to more rapidly evaluate the welfare status of individual animals is also a critical goal. Welfare assessments therefore also take the form of proactive and ongoing monitoring that provides an overview of the current welfare state of individual animals. To that end, the Detroit Zoological Society developed a welfare assessment tool in 2014 which was made freely available in a peer-reviewed publication in the Journal of Applied Animal Welfare Sciencein 2015. If you would like to read the full article, please visit our resource center on the CZAAWE website at czaw.org/resources and click on the link for A Universal Animal Welfare Framework for Zoos.

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Since that time, we have continued to refine the animal welfare assessment tool to evaluate how the animals living at the Detroit Zoo and Belle Isle Nature Center are faring, as well as train other accredited organizations in the use of the tool. In its present form, the assessment tool includes measures of inputs, which focus on what is provided to animals, such as amount and complexity of their space, the social opportunities they have and their dietary considerations. The tool also incorporates measures of outputs, which are how the animals respond to what is provided to them. We try to make sure that we have output measures that match up with the questions about the inputs. For example, the outputs we would use to correspond to the inputs I listed as examples would include questions about how the animals use their habitat, if they interact with other animals that share their space in the manner we would expect and if they are in good body condition. The questions in the animal welfare assessment tool line up with the Five Domains model of welfare, which delineates how nutrition, physical health, behavior and the environment (both physical and social) feed into an animal’s emotional state.

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Organizations accredited by the Association of Zoos and Aquariums (AZA), which we have been a member of since 1985, continue to place increasing importance on ensuring animals in their care are experiencing positive welfare, and this responsibility is reflected in the very standards by which member organizations must abide to be accredited. One of the newer standards requires AZA members to have a welfare assessment process like the one the Detroit Zoological Society has in place. It is great to see that our professional community is committed to not only provide good care for animals, but to provide them with great welfare.

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– 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: Grizzly Bears Really Dig Their Expanded Habitat

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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.

 

Experience our Digital Animal Observation Trek

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The Detroit Zoo is widely known for its expansive and naturalistic habitats. From the 4-acre Great Apes of Harambee to the 4-acre Arctic Ring of Life, these spaces provide the animals with plenty of room to roam and to demonstrate natural behaviors that enhance their well-being.

It is because of this that the viewing experience for guests is similar to what it’s like when observing animals in the wild. It requires patience and an understanding of our animal welfare philosophy to ensure the individuals in our care have choice and control over how and where they spend time in their habitat. A variety of viewing areas are incorporated into the habitats’ design for guests to have the chance to walk around and observe the animals’ behaviors throughout the entirety of the space.

We also give guests curated suggestions of how to explore the Zoo in different ways through our interactive mobile map system called Detroit Zoo Treks. Guests can choose among several timed treks, a Fitness Trek, one that focuses on our wildlife conservation and animal rescue work, one that highlights our award-winning sustainability initiatives, and the new Animal Observation Trek. This latest trek provides visitors an opportunity to share their observations of animals with Detroit Zoological Society staff through simple surveys that can be completed on a mobile device. The digital trek currently features six animals: otters, lions, giraffes, kangaroos, wolves and eagles. As guests visit each of their habitats, they can access the survey and indicate if the animal is currently in view.

If the animal is visible, guests are asked to share what behaviors they observe the animal engaged in. After submitting their observations, information on how to distinguish between individual animals is shared through the system. If an animal is not viewable, guests are then prompted to look for signs of where the animal may have been previously spending time in the space. When the survey is submitted, a tip on where the animals prefer to spend their time in the habitat is shared to help guests observe them on their next visit. All of the survey results are recorded and shared with DZS staff, which is added to their own research and observations about where and how the animals are choosing to spend their time.

The Detroit Zoo Treks are based on a map of the Zoo and include important locations such as rides and attractions, concessions, restrooms and other guest amenities. To participate in the Animal Observation Trek on your next trip to the Zoo, visit www.dzoo.org/trek and select your digital adventure.

Fundraising Gala Highlights New Habitats that Promote Great Animal Welfare

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Whenever we design and construct a new animal habitat, our focus is on ensuring it is expansive, naturalistic and meets the animals’ specific needs. These spaces should provide the animals with opportunities to do the things that are important to them – be it climbing trees, swimming, wallowing in the mud, and interacting with social partners (or avoiding social partners if that’s what they want at any given time).

Attendees of the Detroit Zoological Society’s (DZS’s) annual fundraising gala, Sunset at the Zoo, on Friday, June 7, will have the opportunity to observe two newly renovated and expanded spaces in the Detroit Zoo’s Asian Forest that succeed in doing just that.

A few months ago, red pandas Ash, Ravi and Ta-shi moved into the Holtzman Wildlife Foundation Red Panda Forest. DZS staff immediately began making observations to determine the effect of the new space on the well-being of the animals. We call this a “post-occupancy evaluation” – in this case, it consisted of behavioral observations on each individual as they explored their home. We spent eight weeks monitoring where they chose to spend their time and how their behavior varied based on a number of different factors, including noise levels and if guests were present in a new way the habitat provides. A 70-foot long canopy walkway extends through the trees of the space, allowing visitors to have a red panda’s-eye view.

 

Through these observations, we learned exactly what we hoped for – the red pandas demonstrated diverse “activity budgets”, which means they engaged in different behaviors throughout the day. We were really pleased to see that Ash and Ravi explored and scent-marked their space, both signs that it is stimulating for them. Ta-shi spent a bit more time inactive than the others, which is not surprising given that she is older.

The red pandas made use of most of their space, but did have some preferences, including spending time high up in the trees. This is a natural tendency for the species, and we were glad to see them use the elevated features. Having visitors present on the bridge did not seem to change their preferred resting locations, although Ash occasionally stayed inside the holding building when the habitat first opened. In order to allow the red pandas to acclimate to their new surroundings, we provided them with the choice to go inside their respective buildings. Enabling animals to choose where to spend their time is an important factor in ensuring positive welfare. This ability to retreat was also helpful when noise levels rose, primarily due to the construction happening at the Devereaux Tiger Forest close by. We were thrilled to see that Ash, Ravi and Ta-shi found their home to be a great place to live, letting us know that all of the planning that went into this habitat expansion was successful.

 

Our next post-occupancy evaluation will focus on the Devereaux Tiger Forest. The tiger forest will significantly increase the amount of space for tigers. Naturalistic features, including caves, trees, elevated areas, a waterfall and pool, have been incorporated in order to promote species-appropriate behaviors. We look forward to assessing how the new habitat impacts the well-being of the tigers when the habitat opens this summer.

This year’s Sunset at the Zoo celebrates the Asian Forest, which includes both the tigers’ and red pandas’ new digs. On the evening of Friday, June 7, guests will have the opportunity to explore the Holtzman Wildlife Foundation Red Panda Forest and take a sneak peek at the new Devereaux Tiger Forest. Just as the red panda habitat includes an exciting new experience for guests with the canopy walkway, the tiger habitat has a thrilling element of its own. In addition to expansive acrylic viewing windows, an SUV will be positioned half in the habitat and half out, allowing visitors to sit in the driver’s seat – and a tiger might just lounge on the hood.

Proceeds for Sunset at the Zoo benefit the Detroit Zoological Society’s mission of Celebrating and Saving Wildlife.

– 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: How do You Know if They’re ‘Happy’?

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Think about the term, “animal welfare”, and what it means to you. When you encounter an animal – in any setting, be it a zoo, a friend’s house or even your own living room – are there certain cues that help you decide if you feel the animal is having a good or a bad time – or experiencing positive or negative welfare? It may be the animal’s appearance, behaviors, what the space looks like where they live, or perhaps it’s based on your knowledge about that species.

In some cases, it’s relatively easy to determine that an animal is in a poor welfare state. If they’re living in dirty and cramped conditions, don’t have access to social partners – or perhaps too many – or if they have obvious signs of injuries or illness without any indication they’re under veterinary care, it’s likely the animal is not experiencing good welfare. But when you look at other, less obvious factors, such as if the animal is quietly resting in a spacious habitat, or if the animal is moving back and forth in one area of their space, the answers are less clear.

The concept of animal welfare refers to an animal’s physical, mental and emotional states over a period of time. It is based on the individual’s experience, which can be different from one species to another, and from one animal to another. It is not about what is provided to an animal, such as food and water – this doesn’t automatically ensure good welfare. Although having access to these resources is critical to creating conditions that may lead to good welfare, it is actually how the animal perceives those conditions that determines their welfare. We can’t simply measure welfare in terms of square footage, gallons of water or the nutritional content of food items. We must use indicators from the animals themselves, such as behavior, physical condition and even emotional responses.

These indicators represent the three different concepts of welfare. The first has to do with an animal’s ability to engage in natural behaviors, or live in a way it has evolved to. The second involves biological functioning and prioritizes an animal’s physical health. The last focuses on the animal’s feelings and emotional states, with an emphasis on minimizing negative emotions and promoting positive ones. Should we favor one concept over another, it is possible we would miss something important to an individual animal.

If two people were to assess an animal using two different concepts, they could come to conflicting conclusions about that animal’s welfare state. This is why we incorporate aspects of all three of these concepts when evaluating animal welfare. This allows us to gain a much more holistic picture of the animal’s experience and to consider all of the factors that impact their 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.

Detroit Zoological Society’s Online Resource Center Expands Knowledge of Animal Welfare and Ethics

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When the Detroit Zoological Society (DZS) created the Center for Zoo and Aquarium Animal Welfare and Ethics (CZAAWE), one of the main goals was to increase the knowledge about the welfare of animals living in the care of humans. We developed an online resource center, which is regularly updated, to ensure as much information about animal welfare and ethics can be easily found. Dr. Matt Heintz, an animal welfare research associate for the DZS, stays up to date on newly published articles and is responsible for growing this incredible resource.

The database now contains more than 7,000 references, with some dating back as far as 1932. It represents a broad range of topics as the expansive field of animal welfare continues to grow. Users can search for specific topics, species and authors. Each entry includes a summary of the publication and a link to where the full article can be found. Some are made freely available to anyone by the journal publishers, while others may require a fee or access through subscriptions. The CZAAWE online resource center and the searches that can be performed are entirely free, as access to knowledge is important in our collective efforts to better understand animal welfare and ethics. This database has proven to be a valuable resource and in just the last four years, it has been accessed more than ten thousand times by people in 102 countries.

Dr. Heintz analyzed the database to look for trends in the literature and to help identify gaps in the knowledge currently available. Although a wide breadth of welfare topics are represented, much of the published literature is focused on mammalian species. This tells us that more research needs to center on amphibians, birds, fish, invertebrates and reptiles. He also found a fun way to visually represent the trends using a word cloud image. The terms that are more commonly found in the references are shown in a larger font.

The goal of increasing knowledge about animal welfare and ethics is an important one and we will continue to dedicate ourselves to increasing the usefulness and accessibility of this resource. If you want to learn more about animal welfare and ethics, we encourage you to check out the online resource center, which can be found at www.czaw.org/resources. The more we know, the more we can contribute to promoting great animal welfare.

– 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: A Red Panda’s-Eye View

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There are many questions I’d like to ask animals. In the case of the red pandas who live at the Detroit Zoo, one question would have to do with their newly expanded and renovated digs. Ash, Ravi and Ta-shi have moved into the Holtzman Wildlife Foundation Red Panda Forest, where so much work has been done to ensure they will enjoy this wonderful habitat.

It would be nice if we could channel our internal Dr. Doolittle and simply ask them what they think, but what would be the fun in that? Since we don’t share a common language with red pandas, our challenge is to figure out what they are telling us using means other than traditional human communication. To determine the impact of the Red Panda Forest on the well-being of the three red pandas, Detroit Zoological Society staff are conducting behavioral observations on each one of them as they explore their home.

Red pandas are endangered and native to Asia’s high-altitude temperate forests. With 50 percent of their natural range in the eastern Himalayas, they are well-suited to the cold temperatures and snow we experience in Michigan. Red pandas use their long, bushy tails for both balance (as they traverse tree canopies) and protection from the elements. Although they are a carnivore species, they are actually leaf-eaters, with bamboo comprising the primary component of their diet in the wild. They are also crepuscular, meaning they are most active early in the morning and later in the day, with their natural breeding season during the late winter months.

Detroit Zoological Society staff have been caring for red pandas for several decades. This experience proved invaluable when designing the new features in their habitat. The Red Panda Forest incorporates tall, natural trees to create a complex arboreal pathway, as well as a flowing stream and misting areas. One of the really cool aspects of the habitat is the suspension bridge that brings us eye-level with the pandas when they are in the tree canopy. Not only does this offer us a great view of the pandas, but it will also allow us to gain a better understanding of what they are experiencing. What does the world look and sound like from that height? Part of promoting good welfare for an animal is to be sensitive to their perception of the word around them.

We look forward to uncovering how the three red pandas use their new habitat, including how each one differs in their behavior and preferences. Knowing this enables us to create opportunities for each of them to thrive. We hope you check out the Holtzman Wildlife Foundation Red Panda Forest during your next visit to the Detroit Zoo and see this incredible new space for yourself.

– 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: In the Dark – Aardvark Well-Being

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If you share your home with an animal companion, have you ever wondered what he or she does when you are not home? Some people install cameras that allow them to use their phones to take a peek at what their dog is up to, or where the cat is spending her time. We also wonder about what animals do at the Detroit Zoo when we are not here, and this is especially true for nocturnal animals who are most active when we are sleeping. Aardvarks are one of those species, and the Detroit Zoological Society has been using cameras to study their behavior.

Aardvarks are native to sub-Saharan Africa, and not only are they primarily nocturnal, but they are also fossorial, meaning they dig and burrow underground. This makes them even more challenging to observe, as you can imagine! The four aardvarks who live at the Detroit Zoo are cared for by the night keeper unit, whose hours allow for expanded opportunities for animals, including those who are active later into the night. The staff come up with creative ideas to engage the aardvarks and stimulate natural behaviors.

We installed a number of infrared cameras in the habitat, allowing us to record what the aardvarks do and where they choose to spend their time. Initial research revealed that they had specific preferences, such as sleeping in culverts, which are reminiscent of underground burrows, and that their activity levels varied by individual. Roxaanne, one of the females, preferred to stay up much later than the others, for example. Additionally, we found that when the aardvarks engaged in more investigative behaviors, they had lower fecal glucocorticoid metabolite (FGM) concentrations. Decreased levels of FGMs have been correlated with lower stress levels and overall positive welfare. By taking behavior and hormones into account, we get a more comprehensive picture of the well-being of the aardvarks under different conditions.

Jennifer Hamilton, DZS animal welfare programs coordinator, worked with the animal care staff to develop a new project aimed to increase behavioral opportunities for the aardvarks, by specifically targeting more foraging and investigative behaviors. Jennifer and a small team of dedicated volunteers watched more than 220 hours of “aardvark television”. Talk about binge-watching reality TV! In addition to the behavioral data, the care staff once again collected daily fecal samples on each aardvark so that we could analyze them for FGMs.

Higher levels of investigative behaviors were again linked to lower levels of FGMs. This suggests that these types of behaviors are important for aardvarks and need to be encouraged. The behavior data also showed that foraging opportunities were used for longer periods of time when initially presented, but that investigative opportunities were used more as the night went on. As part of the project, the aardvarks were presented with seven opportunities once a week for eight weeks. We were able to confirm that the aardvarks did not lose interest over time, meaning that repeated interactions don’t bore them! Finally, the aardvarks’ use of the opportunities differed based on their location. The aardvarks have access to different spaces, which vary in their substrates and features. One of the spaces has a very large and deep dirt area, and the aardvarks spent less time engaged in the extra opportunities provided when in that habitat. This may be indicative of a flexible value system, with less value placed on additional opportunities when overall conditions may already be more stimulating. This is an important concept as we explore what type of choices are meaningful to animals and how to create environments that enable them to thrive.

– 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: The Sensory World of Wildlife

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What sounds do you hear when you wake up? I sometimes hear my dog gently urging me to get out of bed. Sometimes I hear a car alarm, which is less pleasant. What do feel when you wake up? For me, it’s my toasty warm sheets and if I’m lucky, I can reach my hand out and pet my dog on the head. What do you smell? What do you see? What about during the day, or at the end of the day? We experience sensations all the time, even when we aren’t awake to realize it. What do those sensations mean to you and how do they affect how you behave?

Animals experience all of the things we do, but not necessarily in the same way. For example, depending on how their sensory systems function, they may smell things much more strongly than we do. A dog’s sense of smell is approximately 40 times stronger than ours. This means what odors we notice may be negligible compared to what they do. While humans typically rely on their eyesight as their primary sense, many animals see differently than we do. Birds and reptiles can see in the ultraviolet range. Raptors can see much further than we can, and some animals see more of what’s around them due to the placement of their eyes. Some animals, such as pit vipers, sense things using infrared sensors, which allows them to find their prey using heat signals. All of this means that animals experience the world very differently than we do, and this can impact their welfare. The senses of animals are essential for every aspect of their daily lives, from finding food and shelter to recognizing others as friend or foe.

If we are concerned about the well-being of animals, we must be aware of how they experience the world around them. We must also be considerate of how our actions can affect their perception. Animals living in their natural habitat are becoming more vulnerable to our actions, from birds colliding with buildings that are lit up at night, to frogs who have to compete with man-made noises to hear one another.

When it comes to animals living in the care of humans, this can also prove to be a challenge. We don’t know enough about how other species perceive their world, but we use the knowledge we do have to make the best possible decisions. For animals living in zoos and aquariums, we have a lot to consider. Ultimately, we are the architects of the homes for other species. Imagine if a zebra was in charge of designing your home. What if a snake built your office? The field of sensory ecology, which is the study of how organisms acquire, process, and respond to information from their environment, continues to grow. We use that information to help create habitats at the Detroit Zoo and Belle Isle Nature Center that provide animals with positive experiences. Additionally, we take the sensory perception of animals into consideration when we plan special events and construction projects, as sounds, sights and smells may impact individual animals. We also think about what animals live near each other. Can an animal feel threatened or positively stimulated by the sight, sound or smell of another species?

In our own lives, we are aware of which sensations make our experiences positive and which don’t. We are often in control of those experiences, or we know they are temporary. Animals may not have those opportunities, and it is our responsibility to ensure we are creating positive experiences and minimizing our own contributions to impacts on welfare resulting from sensory inputs. Take a moment to think about the experiences of the animals who share your home with you. Is there room for improvement? If so, come up with ways to mitigate any negative sensory impacts. Also, take time to think about how the animals as the Zoo feel if people yell at them or create conditions that alters their ability to use their senses.

Those of us who care for animals for a living have to be extremely sensitive to the ways animals perceive their environment. This important concept is part of what the Detroit Zoological Society’s Center for Zoo and Aquarium Animal Welfare and Ethics teaches each year during our workshops. We immerse the participants in animal habitats in various ways in order to change our own human perspective. The understanding each person gains from these experiences is an invaluable part of their toolkit to further the welfare of every animal with whom they work and live.

– 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: Seal of Approval

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The Detroit Zoological Society (DZS) is investigating the effect of foraging opportunities on the welfare of the seals who live at the Detroit Zoo. Foraging is a very important behavior category for animals, as it typically involves mentally and physically stimulating behaviors. Wild gray seals may spend up to two-thirds of their time searching for food. Although they do have well-developed hearing and sight, seals often rely on their extremely sensitive whiskers to locate the fish they eat. This is necessary as visual conditions underwater can be poor and swimming fish may not generate much noise as they move. Instead, the fish – and other prey items – create vibration trails in the water and these are the stimuli the seals’ whiskers detect. Research has shown that harbor seals can use their whiskers to distinguish between objects of different sizes and shapes – a skill they can use to select better prey items when hunting.

Seals living in zoos and aquariums don’t need to forage in quite the same way as they would in the wild, and thus may not engage in as many complex feeding behaviors. As part of her residency with the Center for Zoo and Aquarium Animal Welfare and Ethics, Sara Zalewski worked with DZS staff to design a project examining the impact of three different ways to increase foraging behavior in the gray and harbor seals living at the Detroit Zoo. The seals were presented with fish frozen in ice, fish placed on top of a floating disk and sunken tubes the seals needed to manipulate to allow fish to fall out of holes in the tube. All three items were used to increase the amount of the work the seals would have to do to get to the food. As part of this research, Sara found that the seals differed by both species and individual in how they used the items.

The gray seals interacted with the items most when they were first presented with them, and the harbor seals’ level of interaction increased as time went on. The likely explanation for this is that the gray seals were younger and more dominant, and thus were able to use the items more easily. Once they had their fill of the food, they would lose interest and the harbor seals could begin to investigate the items. Dealing with dominance hierarchies can create challenges when providing animals with resources, and is therefore something we have to keep in mind when thinking about the welfare of all of the individuals.

Another challenge was getting the seals to use the items for longer periods of time. It makes sense that less interaction occurs without the motivation of obtaining food, so there is a need for more challenging devices that require the seals to use more of their foraging abilities. One unexpected outcome was that Georgie, one of the female gray seals, would sometimes use a floating disk as a resting place later in the day. However, it could not support her body weight, so she would lay on it on top of something else, such as a ledge in the pool. Other studies have shown that gray seals’ preferred prey, haul out sites, and feeding locations and techniques differ greatly between individuals. Finding ways that items can serve more than one purpose and allow each seal to make use of them as they choose are also goals.

Harbor seals are an especially playful species, including as adults. However, as animals age, play and exploratory behavior tend to decrease, regardless of the species. Additionally, decreases in their sensory abilities may occur. This means that for Sydney, the older male harbor seal, opportunities may be more challenging or potentially less engaging for him.

In order to create more engaging ways for all the seals to forage, Sara worked with DZS staff to refine the items and will observe Georgie and Jersey, the two gray seals, and Sydney, the harbor seal, to see how the modifications affect their behavior. DZS staff members are creating floating devices that the seals can use to rest – as well as interact with for access to fish – and are changing the design of the tubes so that they rest standing up, rather than lying flat on the bottom of the pool. This should make it a bit harder for the fish to fall out, and will be more stimulating for the seals as a result. Finally, Sydney will have some alone time with the items, to ensure the younger and more agile females don’t deplete the food before he has a chance to interact with the foraging devices. During your next visit, you may see these items in the seal pool at Arctic Ring of Life. Although we are only observing the seals at specific times, incorporating these types of behavioral opportunities is part of our daily comprehensive program of ensuring the environments for all the animals at the Detroit Zoo are ever changing and appropriately complex.

– 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.