March of the Penguins: A Tough Egg to Crack

This month, the Detroit Zoological Society is bringing you not one, but three blog posts centered around our favorite flippered friends — the penguins who live at the Polk Penguin Conservation Center. (read the first blog post, here) The facility, which had been closed since 2019 due to waterproofing issues, reopened in February, and we can’t wait to share with you all the stories we have been saving over the past two and a half years. 

Next in our March of the Penguins series, learn how animal care staff saved the life of a hatching macaroni penguin.

We’ve all heard stories from friends and family of difficult birthing events, sometimes resulting from a baby that is positioned incorrectly in the birth canal, often called a breech delivery. You may not realize that something similar can happen during the hatching of a bird. 

Fertilized eggs contain all of the nutrients needed to support a chick during development. As the chick grows, an air pocket forms at one end of the egg. For a chick to survive, it must be positioned so that it can push its beak into this air pocket just before it’s time to begin hatching. Some developing chicks are rotated or positioned incorrectly so that they can’t reach this air pocket – this means that the chick can only survive if given assistance. Over the years, bird and veterinary staffs have worked together to assist the hatching of several developing eggs.

Looking inside of a penguin egg.

The bird staff monitors eggs under development very meticulously. They take daily weights to ensure eggs steadily lose weight, a sign that the air pocket, (otherwise known as an air cell) is growing larger.  The staff also shines a special bright light through the eggs, a procedure called candling. Candling allows you to see an outline of the developing chick and air cell. Once incubation nears the end, radiographs can also be taken to visualize the skeleton of the chick and ensure the embryo is positioned normally.

In 2021, the Detroit Zoo had a single fertile macaroni penguin egg. On day 37 of a 37-day incubation period, radiographs were taken to see if the chick was able to hatch normally. The radiographs showed the chick was malpositioned in a way that can be fatal — the chick was rotated, and the beak would not be able to reach the air cell. We could feel the chick moving, and it seemed strong. After discussing our findings, we decided to begin the process of assisting the chick to hatch. 

Dr. Ann Duncan helping the chick hatch.

The shell was cleaned gently, and a Dremel tool was used to make a small opening. A sterile tool was then used to gradually make the opening larger until the position of the chick’s beak could be confirmed.  We then made a very small hole in the membrane overlying the chick’s beak. This allowed the chick to begin breathing air, so that it can stay strong and continue hatching. Chick embryos develop with the yolk sac outside of their abdomen, and as they near hatching, the yolk sac is gradually enveloped inside of the belly to provide nutrients for the first few days. Through the opening in the shell, we could see that the chick needed more time to absorb the yolk sac. We set the chick up in a warm, humid environment, and checked on it frequently. We also began offering one or two drops of water every few hours. 

She has arrived!

The next morning, we were very happy to see that the yolk sac had been mostly absorbed. We removed more of the shell to expose the belly, cleaned the skin over the belly and placed a suture to hold things in place. We then gently coaxed the chick out of the shell. In all, the hatching process took about 24 hours, which mimics the timeline of normal hatching. The macaroni chick is doing well, and is currently learning to swim in the Polk Penguin Conservation Center. She was named Betty and as you can see is full of character. We are very happy to have been given the opportunity to get her started on a long, healthy life.   

Betty in the Polk Penguin Conservation Center.

– Dr. Ann Duncan is the director of animal health for the Detroit Zoological Society.

March of the Penguins: A King-sized Bundle of Joy

This month, the Detroit Zoological Society is bringing you not one, but three blog posts centered around our favorite flippered friends — the penguins who live at the Polk Penguin Conservation Center. The facility, which had been closed since 2019 due to waterproofing issues, reopened in February, and we can’t wait to share with you all the stories we have been saving over the past two and a half years.

The Detroit Zoo was very eager to welcome a king penguin chick who hatched in 2020. Even though we have raised many penguin chicks throughout the years, we haven’t raised a king penguin chick in 19 years, so this was truly a “king-sized bundle of joy!”

The rearing of this chick is also an interesting story. During courtship, king penguin pairs form a tight bond, which culminates with the laying of a single egg. Unexpectedly, this was not the case for the parents of this chick. Once the egg was laid, the pair was moved into the rookery with the egg. The rookery is an area within the penguin habitat that provides some separation and privacy while the pair incubates their egg and raises their chick. The female was immediately receptive to the male, lifting her brood patch and showing the male their precious egg. The male appeared receptive initially, but rather than soliciting the egg transfer, he quickly became aggressive towards the female.

Normally, the female will transfer the egg to the male shortly after it is laid, usually within 24 hours. Both will share incubation duties, with the male completing the larger share. We decided to give the male a fake egg for a couple of days, while the female incubated the real egg.  After several days, he proved to be a good egg incubator but was still aggressive towards the female. Once the egg was determined to be fertile, we gave it to the male but knew that we had to develop an alternate plan for rearing this chick. 

Fortunately, another pair whose egg was not fertile met the criteria for becoming foster parents. Egg fostering is a technique we have used in the past with other penguin species, either to give another pair the opportunity to rear a chick or when a pair is not able to rear a chick. The foster male (and the biological male) are actually the last of three king chicks to be reared here 19 years ago. Although the foster male had never raised a chick before, the foster female had raised a couple of chicks previously. In fact, she raised the biological “father” 19 years ago, and therefore is the “grandmother” of this chick!  We initially gave the foster pair a fake egg, and about halfway through the incubation period, we transferred the real egg from the biological male to the foster male.

The average incubation period for king penguin eggs is 54 days. On day 54, we noticed an empty eggshell on the ground near the parents – the chick had hatched! Since then, the male chick has fully grown and was given the name Archie. We love seeing this “royal” bird in the habitat and remembering the special foster story that made it possible.

Come visit Archie and watch this fabulous flock waddle, dive, swim and display other natural behaviors in the Polk Penguin Conservation Center.

Bonnie Van Dam is the curator of birds for the Detroit Zoological Society.

Welcoming the Great Ape Heart Project with Open Arms!

This photo of chimpanzees Zuhura and Akira was taken by Roy Lewis.

Earlier this month, we announced that the Great Ape Heart Project has officially moved to the Detroit Zoo!

Since 2010, the GAHP has dedicated time to understanding and treating heart disease in great apes. Much like it is for humans, heart disease is the leading cause of death observed among great apes in zoos.

“The Great Ape Heart Project was created to address a specific need in the zoological community,” said Dr. Hayley W. Murphy, director emeritus of the GAHP and executive director/CEO of the Detroit Zoological Society (DZS). “It’s critical to investigate, diagnose and treat heart disease among great apes. The information that comes from this international, multi-institutional project saves lives around the world.”

This photo of gorillas Kongo and Pende was taken by Roy Lewis.

Originally based at Zoo Atlanta, this collaborative project was founded to create a centralized database that analyzes cardiac data, generates reports and coordinates cardiac-related research.

“For more than a decade, the project has maintained a hub for researchers that includes more than 90% of the individual great apes in institutions that are accredited by the Association of Zoos and Aquariums (AZA). The project allows participants to compare and contrast data from nearly 80 institutions,” said Dr. Marietta Danforth, director of the GAHP. “Prior to this move, Detroit was like a second home for us because we had so many fruitful meetings here at the Zoo. It’s exciting to have it be our home base now.”

The GAHP received the prestigious 2020 Research Award from the AZA. The award recognizes achievements in advancing scientific research among accredited zoos and aquariums throughout the U.S.

In honor of Heart Month, we are selling GAHP shirts here: bonfire.com/GAHP2022. All proceeds will help prevent, diagnose and treat heart disease in great apes. This year’s design features two chimpanzees who live at the Detroit Zoo, Zuhura and Akira

Pip Pip Hooray for a Little Piping Plover

Let’s open this blog post with a little fun. We recently held a gender reveal and Erie, the piping plover under human care at the Detroit Zoo, is a GIRL! Not only is Erie a girl, but she is also the granddaughter of the Illinois pair from Montrose Beach, Monty and Rose.

Erie’s background:

For the first time in 83 years, piping plovers were seen nesting in Ohio. Birds Nellie and Nish quickly became a famous, feathered pair when they decided to make Maumee Bay State Park their temporary home. Of note, Nish (the male) is the offspring of Monty and Rose, the infamous piping plover pair in Chicago (about whom a book was written). On July 1, all four of their eggs hatched. The chicks – Erie, Ottawa, Maumee and Kickapoo – were given some serious security detail. A large part of the beach was cordoned off until early August to protect the young birds.

People with a passion for plovers watched this Great Lakes critically endangered species closely. Black Swamp Bird Observatory volunteers and other bird watchers gathered for weeks with binoculars, cameras and notebooks. Daily updates were posted to Nellie & Nish: The Maumee Bay Piping Plovers Facebook page.

Photo taken by Plover Patrol Volunteer Ron Schramm and posted on the Nellie & Nish Facebook page.

On August 18, hearts were broken when a volunteer found Kickapoo dead. It is believed the bird was killed by another wild animal. The next day, more difficult news was shared when it was noticed in photographs that Erie had suffered an injury to her cloaca. The cloaca is the opening for a bird’s digestive, urinary and reproductive tracts. It’s used to expel feces and lay eggs. An injured cloaca could cause chronic medical problems, as well as make it difficult for Erie to lay eggs when she is nesting.

After much discussion with wildlife agencies and piping plover experts, the decision was made to capture Erie and transport her to the Toledo Zoo for treatment. During this time, siblings Ottawa and Maumee did what piping plovers do and migrated south for the winter. It is believed that had Erie left with the others, she would likely not have survived.

Photo of Erie taken by Vince Capozziello and posted on the Nellie & Nish Facebook page.

After nearly two weeks of treatment, Erie’s injury was healing well and she was returned to the beach. Everyone expected her to head south like Nellie, Nish, Ottawa and Maumee already had – but in mid-October she was still at Maumee Bay State Park.

That’s where the Detroit Zoological Society (DZS) comes in. At the U.S. Fish & Wildlife Service’s (USFWS) request, Erie was captured and transferred to the Detroit Zoo, where we are providing medical care and a private, comfortable home for her over the winter. Our experience caring for piping plover chicks as part of the federal recovery program’s salvage captive rearing program makes the DZS a perfect fit for helping Erie. Every year, piping plover eggs that are abandoned are collected, incubated and hatched on the DZS campus and chicks are later released back to various Michigan shorelines. This program has been very successful; the Great Lakes population of piping plovers has increased from 17 breeding females in 1986 to 74 breeding females in 2021.

In the last two months, we’ve been able to watch Erie’s personality really develop. She is laid back and loves all kinds of bugs! Staff at the DZS will assess Erie’s health over the winter and release her next summer with a group of captive-reared chicks. If it is believed that her injury could present risk to her, such as causing problems when she tries to lay eggs, she may be deemed non-releasable by the USFWS and we will help to find a permanent home for her in a zoo that houses piping plovers.

Bonnie Van Dam is the associate curator of birds for the Detroit Zoological Society.

An Enriching Experience: My Time as an Animal Welfare Intern

By Bailey Brocco

What do gorilla hormones, water monitor tongue flicking, penguin swimming duration and aardvark habitat use all have in common? They are all studied by staff at the Center for Zoo and Aquarium Animal Welfare and Ethics (CZAAWE) as indicators of animal welfare! Animal welfare refers to the mental, physical and emotional state of an animal throughout their lifetime. Animals can’t talk to tell us how they’re feeling, but that doesn’t mean they can’t communicate. Just like humans, animals behave differently under different circumstances. There are many non-verbal indicators that animals may use to communicate their needs and well-being. Their posture, eating habits, social interactions, space use, hormone levels and much more can all serve as clues to tell us how they are doing. CZAAWE staff are dedicated to assessing and improving the welfare of all the animals at the Detroit Zoo and Belle Isle Nature Center. My name is Bailey, and I am a senior at Oakland University majoring in biology. This fall, I was fortunate to join CZAAWE as an intern and dive into what it really means to study animal welfare.

At any given time, CZAAWE is conducting research across a number of species. Each project requires its own special training, as different taxa have their own species-specific behaviors used to evaluate their wellbeing. As an intern for CZAAWE, I contributed to multiple ongoing welfare projects. I worked on projects involving aardvarks, gorillas, polar bears, a water monitor, San Esteban Island chuckwallas, penguins and red kangaroos. Each group of animals had their own ethogram, a reference describing their behaviors, which made each study a unique experience. I might record several different behaviors in the span of a minute when observing the aardvarks, but only one behavior within ten minutes for the chuckwallas. Each project varied not just in terms of the behaviors we monitored, but the questions we asked. For the kangaroos, we focused on their interactions with novel enrichment in different areas of the habitat, while we investigated the degree of visibility in the resident chuckwallas.

Solair a water monitor

Even though a study might include an entire group of animals, animal welfare is measured at the individual level. The Detroit Zoological Society’s campuses are home to thousands of animal residents, which means taking each of their individual needs, personalities and behaviors into account. The aardvarks are a great example. Aardvarks are nocturnal animals, so it is difficult to observe them during the day. Instead, we study their behavior using camera footage collected during the night when they are active. I really enjoyed my time watching them because of how different each one is. Baji, the only male in the group, is very social and inquisitive. Roxaane is the oldest female and more laid back. She enjoys sleeping, but she’s also very food driven. What is usual and expected for one individual might be uncommon for another. While observing animal behavior is very important (and fun), it is only one of many ways to assess animal welfare. 

Another important indicator of welfare is hormones. Hormones offer some insight into the physiological state of an individual. There are many ways to measure hormones, but one of the least invasive ways is through the collection of fecal samples. Part of my time here has been spent crushing gorilla and polar bear fecal samples and learning how to extract hormones from them in CZAAWE’s Endocrinology Lab. This state-of-the-art lab is completely dedicated to gathering and processing data on hormones and other biomarkers that offer insight into animal well-being. Although it may not sound very glamorous, being able to analyze fecal samples in a lab is a privilege that not many other zoos have. Using both behavioral and hormonal indicators allows us to paint a more comprehensive picture of animal welfare.

Intern Bailey Brocco

Zoo staff don’t just collect data, they have to process it too. The raw data that is gathered needs to be cleaned and analyzed so it can be used to inform new and beneficial management strategies. In the beginning, cleaning data and organizing it on the computer seemed very daunting to me. However, with some training and practice, I have come to really appreciate this skill. Collecting data is important, but it’s useless if it can’t be analyzed, interpreted and shared. CZAAWE needs to clearly communicate its findings to the many different departments at the Zoo. The ability to concisely organize the data into summaries is just as essential as the rest of work this department performs. I’m grateful that I’ve been able to practice honing these skills.

With new breakthroughs in technology and research, the field of welfare is always growing and evolving. It’s incredibly important to continue to stay up to date on new findings and add to the body of knowledge when we can. CZAAWE has published many of its own studies and findings to contribute to the current knowledge available. Additionally, CZAAWE keeps an online Resource Center, which you can access on their website, full of the most up-to-date research relating to the wellbeing of animals. I spent quite a bit of time searching for new research to add to that database. It was incredible to see the different research people are conducting all over the world in the attempt to learn more about the wonderful animals in our care. 

Every animal is precious, and it is our job to ensure that each and every one of them is not just surviving, but thriving. There is always a lot of work to be done when it comes to ensuring the wellbeing of animals, but welfare scientists work hard to promote the best lives possible for animals. I’m so grateful for the amazing opportunity I was given in interning here at the Detroit Zoo. It has been really eye-opening to see, and participate in, every step of studying welfare. I have a much better understanding of how the process works from conception, to collection and finally to distribution. I have learned so much in the time I’ve spent already, and I’m excited for all the adventures yet to come!            

An Evening of Learning and Bonding for Families in Need

Throughout the COVID-19 pandemic, we have all struggled to grasp the new normal. It has brought new challenges and complicated old ones, yet we continue to push through. The pandemic is especially challenging for people already facing extremely stressful situations, like homelessness and domestic violence. Research indicates that even short respites of spending time in a safe, enjoyable experience can provide much needed relief and reprieve. 

This year, the Detroit Zoological Society hosted several private programs called Nocturnal Adventures. These evening programs catered to more than 270 individuals who are dealing with significant hardship. This positive experience is provided through our partnerships with HAVEN, Turning Point, First Step, the Coalition on Temporary Shelter and the Macomb County Rotating Emergency Shelter Team. The program includes transportation to and from the Detroit Zoo, dinner, a guided evening tour of the Zoo and an education program that focuses on the stories of rescued animals who have found sanctuary at the Detroit Zoo. 

The evening starts with dinner. The meal is shared between the DZS staff, volunteers and our guests. This community building aspect is an opportunity to get to know each other while sharing a meal. We all have more in common than we may first assume and the conversations that evolve are both heartwarming and enjoyable. 

The tour that follows is led by DZS volunteers and education staff. As they lead guests through the Zoo, they share stories of the animals who have found sanctuary after challenging experiences. Many of the animals have suffered injuries in the wild and can no longer survive on their own without human care. Some have come from private ownership where proper care or habitat space was not available. As a result, the animals required urgent intervention and oftentimes specialized care. They are stories of new beginnings and hope.  

Toward the end of the evening, a craft activity provides all participants the opportunity to choose two plants and to decorate a pot for each. The participants can choose to keep and care for both, or to give one to someone. Caring for another living thing and giving are both learned skills. Regularly being on the receiving end of care and support can be taxing on a person, which makes having the opportunity to give or care for something an important element. Taking care of a plant also reinforces that an individual’s choices and actions matter. If the plant isn’t cared for in a manner that meets its basic needs, the plant won’t survive. However, if thoughtfully tended to, the plant will thrive. 

The evenings conclude with the opportunity for participants, staff and volunteers to make s’mores together over a fire pit. This simple, albeit sticky and sweet, ending is a chance to reflect on the evening, share a few more stories and look forward to new beginnings. 

The programs are made possible by dedicated funding from the Detroit Zoological Society and generous donations from the Kellogg Foundation and the Butzel Long Law Firm, an institution deeply involved in Detroit and southeast Michigan for more than 165 years.   

In addition to their financial support, volunteers from Butzel Long had the opportunity to help at a recent event. “We are very happy to have partnered with the Detroit Zoo on the Nocturnal Adventures program. It is our pleasure and honor to give back to our communities, to partner with great institutions like the Detroit Zoo and to do our small part to help those who need it,” said Paul Mersino, attorney and counselor of Butzel Long Law Firm.To support the Detroit Zoological Society’s commitment to providing educational programs for the community, visit detroitzoo.org/support/give/detroit-zoo-fund/.

– Claire Lannoye-Hall is the director of education and D’Nae Hearn is an education specialist for the Detroit Zoological Society.

Protecting Animals Against Infection at the Detroit Zoo

Zoo veterinarians use a range of vaccines developed for use in domestic animals to protect the species in our care. We use vaccines developed for use in domestic pigs to protect our warthogs, vaccines developed for horses to protect our zebras and vaccines developed for ferrets to protect our red pandas. We use human vaccines to protect our chimpanzees and gorillas against measles and polio virus. 

This photo of Pende was taken by Roy Lewis at the Detroit Zoo.

We are very happy to report that in late July we received shipment of a vaccine specifically made to protect susceptible zoo animals against infection with COVID-19. The vaccine was developed by veterinary pharmaceutical company Zoetis, and is being donated to 70 zoos and a dozen other wildlife organizations in the United States. 

During the course of the pandemic, the human and veterinary medical community has been working diligently to understand how coronavirus affects both human and animal health. At the Zoo, we have taken a number of measures to minimize the potential for infection in animals considered susceptible, and we have been fortunate that no animals in our care have contracted COVID- 19. Gorillas, lions, tigers and otters have become infected at other zoos in the United States. 

All of the animal care staff working with these susceptible species has been vaccinated against COVID-19, and we continue to use masks and gloves to minimize spread of infection. Despite this, we worry that supporting the health of an infected tiger or chimpanzee would be much more challenging than a dog or cat, and are extremely grateful to be able to provide vaccine protection against serious illness. 

This photo of Nikolai was taken by Lee Fisher at the Detroit Zoo.

Over the course of the last few weeks, we have been vaccinating the gorillas, chimpanzees, tigers, lions, North American river otters, sea otters and wolverines in our care with this new vaccine.  Each animal will receive two shots, three weeks apart, the same as is recommended for people. None of the vaccinated animals have shown any signs of feeling under the weather after their first vaccine, and we continue to monitor everyone carefully for adverse effects. 

– Dr. Ann Duncan is the director of animal health for the Detroit Zoological Society.

Learn About the Wolf-Moose Project on Isle Royal

The Detroit Zoological Society’s top-notch education staff are always hard at work creating original lessons and content for students and families in metro Detroit and beyond. DZS educational offerings teach students to have empathy for wildlife while providing science, technology, engineering and math experiences – particularly for students who are underrepresented in or lack equal access to high-quality STEM learning. In one highly-popular six-part DZS offering, students practice science from the perspective of professional conservationists researching moose and wolves on Isle Royale.

Isle Royale is part of an archipelago in Lake Superior, an island ecosystem that supports plant and animal life through harsh winters and mild summers. It is also home to the longest-running research project dedicated to a predator-prey relationship in the world. Called the Wolf-Moose Project, the study has documented and analyzed the moose and wolf populations living on the island since 1958, investigating the complex and dynamic relationships between predators and prey while considering humans’ role in the changing ecosystem. 

The Detroit Zoological Society (DZS) supports the work on Isle Royale financially and by sending staff to participate in this study through an annual Moosewatch expedition.  DZS-led Moosewatch teams spend just over a week hiking throughout the island to look for Moose that have passed away. If they find one, they will collect specific bones for the study. Analyzing the bones can provide insight into how the moose died – whether from old age, disease, lack of food or predation from wolves. This information is critical to understanding the health of the ecosystem. 

To bring this powerful story to life for school-age youth, DZS educators created a six-module course for middle and high school students. The on-demand, online learning experience addresses science, literacy and math standards through an interrupted case-study model. In this framework, course participants take on the role of a wildlife biologist who has been tasked with examining data, historical information and other evidence to make an assessment of the health of the island ecosystem. 

Photo taken by Jennifer Harte of Renner at the Detroit Zoo.

Drawing on this information, participants make a recommendation to either continue relocating wolves from the mainland to the islands, in an attempt to slow the rapidly growing moose population, or to let the current populations remain as they are, allowing nature to take its course. The experience is designed to help participants consider the perspectives of several key stakeholders, including conservationists, research scientists and the animals themselves. 

After submitting a recommendation for wolf population management, participants can schedule a time to meet with a Detroit Zoological Society staff member, who can answer questions, provide information about the wolves who live at the Detroit Zoo, and share stories about our conservation work. Several staff have participated in the annual Moosewatch program on Isle Royale and can provide first-hand accounts of the island. There is a charge for this virtual meeting with DZS staff, but the rest of the course is free. 

Gray wolves and humans have a long and complicated relationship. Wolves have been portrayed as villains, both in the media and literature, for generations. The reality is that all animals have an important role in their respective ecosystems, and it is our responsibility to find ways to coexist peacefully. The study on Isle Royale has provided a tremendous amount of information that has challenged our knowledge of predator and prey relationships, and how dynamic they are. This course provides an opportunity for students to learn about these relationships on Isle Royale by making use of real data and experiences – and while building critical skills they will need as our future leaders and decision makers.

Launch the course.

– Claire Lannoye-Hall is the director of education for the Detroit Zoological Society.


Amphibian Breeding Season

Spring is the time of year when most amphibians in the wild are emerging from hibernation, breeding, and eventually laying eggs. This pattern also holds true for the animals at the Detroit Zoo’s National Amphibian Conservation Center (NACC). Every year in the early months of spring, the top-notch staff at the NACC facilitate hibernation, breeding and rearing for endangered amphibians from all over the world with the intention of releasing them into their respective habitats in the wild. A few of these species include Wyoming toads (Bufo baxteri), striped newts (Notophalmus perstriatus) and Puerto Rican crested toads (Peltophryne lemur). Amphibians are highly sensitive creatures who rely on the environmental conditions of their native habitats to cue their natural cycles of breeding and to maintain their overall health.  The NACC staff are experts at recreating these environmental cues.

Facilitating breeding in Wyoming toads, for example, is a complex process involving temperature changes and natural material for burrowing. The amphibian staff use a refrigerator to replicate the natural winter cool down experienced by these critically endangered creatures, and to ease them into a state of lowered activity and metabolism. The amphibians are also provided with a special mix of substrate to burrow into during this period – very similar to how Wyoming toads in the wild burrow below the frost line during the cold months.  When they warm up after this simulated winter, the toads at the NACC are ready to breed and are paired up with mates according to the recommendations of the Association of Zoos & Aquariums’ (AZA) Species Survival Plan (SSP) for Wyoming toads. An SSP is a cooperative breeding program that is overseen by AZA-accredited institutions that breed and house animal species who are endangered or threatened.

Another example of the specialized care required to breed the unique animals at the NACC is found in the reproduction patterns of striped newts. Endemic to the long leaf pine forests of Georgia and Florida, these amphibians are known to congregate and breed in temporary pools during specific times of the year when the water levels are highest.  In order to mimic these events for the striped newts at the NACC, their habitats’ water levels are lowered for a period of time – before being raised dramatically. The natural breeding cues of the striped newts are also replicated in other ways, such as changing their “photo period,” or daylight/nighttime hours, in order to simulate different seasons.  Inside the animals’ habitats, the zookeepers also place specific aquatic vegetation that the newts have been known to prefer as sites for laying eggs.

            Puerto Rican crested toads are among the many amphibians who are known to begin breeding activities during periods of heavy and sustained rainfall. Existing only in several small isolated populations within Puerto Rico, these toads emerge from hiding during seasonal rains to find a mate and reproduce.  Making use of this knowledge, the intuitive keepers at the NACC have produced a “love song mixtape” which includes the calls of male crested toads as well as the sound of heavy rainfall. While this track may not win any Grammy Awards, it serves to stimulate the crested toads into amplexus, which is an embrace used by male toads to hold onto the female and fertilize her eggs.

After countless hours of logging temperatures, researching literature and testing water quality, the real reward comes for the staff at the NACC when these fragile and endangered animals are released into the wild having received a head start towards a brighter future. This year, in the month of June, the amphibian department at the Detroit Zoo released 3,393 Puerto Rican Crested Toads, 634 Wyoming Toads and 41 Striped Newts into native habitats ranging from the dry forests of the Caribbean Islands to the plains of Wyoming. The amphibian staff take great pride in having contributed to the conservation of some of the most important animals on the planet as well as in furthering the mission of Detroit Zoological Society.

– Mark Vassallo is an amphibian department supervisor for the Detroit Zoological Society

What a Lizard Wants

When you walk into the Holden Reptile Conservation Center, directly on your left is a lush habitat full of vibrant plants and the sound of a trickling waterfall. As you walk to the other side of the habitat, you may see a roughly six-foot-long lizard floating in the pool, or he may be stretched out, soaking up the rays from a heat lamp. This is Solair.

Solair is an 11.5-year-old water monitor (Varanus salvator). He arrived at the Detroit Zoo in early 2015 after his previous facility could no longer care for him. Although Solair may be considered a senior for his species, you would never know it! He is a charismatic individual who enjoys interacting with his care staff and exploring his habitat to find the tasty fish they leave for him.

Figure 1: Solair, an 11.5-year-old water monitor, resting in the pool of his new habitat, completed in April 2021.

Solair’s current habitat was completed in April 2021 with the generous support of individual donors and a grant by the Michigan Council for Arts and Cultural Affairs. The habitat is more than 900 square feet, which is almost five times its original size! A major feature is the 7,000-gallon pool with a waterfall. His basking lamp shines in a cave with a heated floor, and two other heated rocks can be adjusted to keep him comfortable throughout the year. Natural light shines through the front windows and skylights, allowing live plants to thrive and creating a tranquil atmosphere. The only piece of the habitat that remains the same from before the renovation is Solair’s favorite log that he likes to climb and where he occasionally sleeps.

Figure 2: Solair is looking out from one of the logs surrounded by plants and natural sunlight.

Major habitat modifications like this come with many considerations. How do we know that Solair likes the changes we made? How do these changes affect his welfare? The Association of Zoos and Aquariums defines animal welfare as an animal’s collective physical, mental and emotional states over a period of time, and it is measured on a continuum from good to poor. To monitor how habitat modifications affect an individuals’ welfare, we perform a post-occupancy evaluation. This evaluation looks at how an animal used their previous space compared to their new habitat.

For a post-occupancy evaluation, we may look at a variety of animal welfare indicators, such as investigation and species-appropriate behaviors. When animals spend time investigating their habitats above the amount required to find food and shelter, it is interpreted as enjoyable and self-rewarding. Due to the energy needed and risks that could arise from investigating in the wild, this behavior can also signify that an animal feels comfortable in their habitat. From his first introduction to his new habitat, Solair appeared very comfortable. He almost doubled his time investigating compared to his previous habitat as he checked out every nook and cranny of his new home. As a water monitor, this included particular attention to exploring every inch of his spacious pool.

Species-appropriate behaviors, like water-based behaviors for water monitors, are considered during all habitat modifications. We want to provide spaces that allow animals to behave as similarly to their wild counterparts as possible. Water monitors have a fascinating repertoire of behaviors seen in the wild. They are usually found by the water and can swim long distances if needed. Water monitors create burrows in the banks of rivers, carving out a chamber with shallow water where they sleep. They have powerful legs that help them chase down prey across land or in the water. Solair’s new habitat has given him the space to spend more time digging, swimming and floating. Solair also has spent more time on land moving between different habitat features, which helps him build muscle and maintain a healthy weight.

Changes in specific behaviors provide hints about overall welfare, but we also try to look at more comprehensive welfare indicators, including behavioral diversity and the spread of participation index (SPI). Behavioral diversity measures the number and frequency of behaviors displayed by an animal. In general, higher behavioral diversity is considered a positive welfare indicator, suggesting an animal has the resources and comfort to perform a variety of behaviors. When Solair was introduced to his new habitat, his behavioral diversity increased partly due to the new behaviors the habitat allowed him to perform.

The SPI has been gaining interest as a welfare indicator, and it assesses how evenly an individual uses the space provided, providing information on how different areas of the habitat meet individual needs. Typical SPI values vary from species to species. For example, grizzly bears generally move more than most snakes. However, suppose an individual never moves from one spot. In that case, the habitat may not provide the resources that the individual needs or the comfort to use the resources provided. Solair uses his current habitat more evenly than his previous one. However, he still has favorite locations, as seen in the heat map of his location use. The pool and his heated cave are two of the places where he spends the most time.

Figure 3: A heat map of Solair’s space use. This map shows the Holden Reptile Conservation center entrance on the right side and the exit on the left side. Areas in blue and green are less used, whereas areas in yellow and red are highly favored.

Solair’s new habitat has many positive features for him and Zoo guests, including ample options for people watching. Frequent visitors know that Solair occasionally will engage with small children and will often watch guests throughout the day. There were also many neutral and mildly positive relationships between the amount of time a crowd was in front of Solair’s habitat and his use of space and behavioral diversity. However, we have noticed one drawback: with the increased glass in the new habitat, guests are tapping on the glass more frequently. Unfortunately, there were decreases in Solair’s welfare indicators on days when guests engaged in more glass tapping. Part of the scientific process is to notice trends in the data and begin asking new questions, revealing new study ideas. The Detroit Zoological Society will continue to do this with the aim of providing the animals we care for with the best lives possible. However, we also ask our guests and wildlife lovers everywhere to remember that you play a part in the welfare of animals at the Zoo, other organizations and in the wild.

Overall, Solair has adjusted well to his new habitat and seems to enjoy all of the new features provided. We hope next time you visit the Zoo, you will make sure to stop by and say hi to Solair in his new habitat. Just remember he prefers a friendly wave over a tap on the glass.

Jennifer Hamilton is animal welfare programs coordinator for the Detroit Zoological Society