Wildlife Conservation: Breeding Eastern Tiger Salamanders

Amphibian breeding season is here! That means it’s time to start helping amphibians get in the mood for love and romance.

The Institution of Museum and Library Sciences (IMLS) recently awarded a $500,000 National Leadership Grant for the purpose of improving reproduction within captive assurance colonies of imperiled salamanders. The Detroit Zoological Society is one of the primary partners on this grant. My doctoral research focused on salamanders, their reproductive physiology and techniques to help them breed, and that very research was the basis for the recent IMLS grant proposal.

Other partners on the grant include Mississippi State University and Omaha’s Henry Doorly Zoo and Aquarium. Now that the grant was awarded, techniques must be taught to the other partners so we can all work together in salamander conservation efforts. I recently visited Mississippi State University in order to train the other principal investigators and the graduate students involved on this salamander grant in principles of natural salamander reproduction and performing assisted reproduction techniques with salamanders.

The training session involved eastern tiger salamanders (Ambystoma tigrinum), which are regionally threatened and endangered in various areas of North America. Like many species of salamanders, the tiger salamander is very difficult to breed in human care. Similar to other species in the “mole salamander” family, tiger salamanders respond to changes in air pressure and temperature when seasonal rain storms occur. These storms are what cue breeding behavior and are very difficult to replicate in human care. Without the ability to provide the appropriate “mood”, tiger salamanders in human care will not often feel romantically inclined. Natural breeding is always the first goal when breeding animals for conservation, but sometimes this is extremely challenging. In these cases, we use alternative techniques while we perfect replicating the natural breeding environment.

In vitro fertilization is a technique used to assist salamanders and other amphibians in breeding. Most salamander species undergo internal fertilization, in which the female picks up a capsule of male sperm, called a spermatophore, which the male has deposited into the environment. The female holds the sperm in an internal pouch that she later empties over her eggs as the eggs are laid. In in vitro fertilization of salamanders, sperm is collected from males by giving them a massage. Eggs are then collected from the female into a small dish where sperm is placed on top of the eggs. Just add water, and presto, you have salamander babies. Of course, it is never just that easy, but the concept is straightforward.

I trained the other primary investigators and students in other techniques as well, including cryopreservation – or freezing and long-term storage – of salamander sperm and sperm quality assessment. The training was very successful, with nearly 100 tiger salamander babies produced. Now the trainees can go on to teach more amphibian conservationists, and we can save more species by assisting with breeding!

– Dr. Ruth Marcec is the director of the National Amphibian Conservation Center at the Detroit Zoo.

Animal Welfare: A Compassionate Approach to Toad Conservation

Staff members from the Detroit Zoological Society’s (DZS) National Amphibian Conservation Center and Center for Zoo and Aquarium Animal Welfare and Ethics are collaborating to find out what toads like. By doing so, we can ensure we are providing for their welfare while they’re in our care and also contributing to the conservation of this species in the wild.

Wyoming toads (Anaxyrus baxteri), also known as Baxter’s toads, are considered extinct in the wild, and their numbers must be bolstered each year by reintroductions of individuals born and reared in the care of humans. They can be found in two locations within the Laramie Basin in Wyoming, thanks to efforts by the U.S. Fish and Wildlife Service and other dedicated organizations including the Detroit Zoological Society.

Wyoming toads were abundant until the 1970s when their numbers began to plummet due to the spraying of aerial pesticides, habitat alteration and the fungal infection caused by chytridiomycosis, which is decimating amphibian populations worldwide. By 1984, the species was listed as endangered and in 1993, that listing changed to extinct in the wild. That year, what were believed to be the last 10 remaining Wyoming toads were brought into a facility to safeguard them and begin a breeding program in the hopes of one day reestablishing the species in the wild.

The Association of Zoos & Aquariums started an official Species Survival Plan for the Wyoming toad in 1996, a program in which the DZS has been very active, including releasing thousands of toads hatched at the Detroit Zoo since 2001. Through the efforts of this collaborative breeding program, more than 1,500 Wyoming toads are currently believed to live in the wild.

Because breeding success continues to be a great concern for this species, the Wyoming Toad Species Survival Plan established strict guidelines for habitat setup at the participating institutions. The habitats are rather sterile to reduce the potential development of any disease processes and consist of a dry area typically made of PVC, a water feature, a basking lamp and a shelter. This type of setup was necessary to properly monitor conditions to promote higher survival rate and breeding success. Due to the success of the reintroduction program, new habitat parameters can be explored, providing the toads with a more stimulating environment.

It is important that we assess how this affects the toads and what preferences they might have. To that end, habitats are being created that provide the toads with a choice between the standard habitat and one that has more naturalistic elements, such as soft substrates, multiple shelters and water features of varying shapes and sizes. With the assistance of our current resident, Emilie Gupta, we will be studying the toads to determine if this choice is important to them. Providing animals with choices and agency – or control – over certain aspects of their lives has been proven to positively affect welfare in some animals. This research will augment what we know about amphibian well-being and will add a compassionate dimension to this conservation success story, in which ensuring the welfare of individuals is a critical part of protecting the species.

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.

Education: Community and Conservation

Four teenaged girls recently assisted the Detroit Zoological Society (DZS) with our amphibian conservation efforts by pairing up with staff members to build mudpuppy shelters at the Detroit Zoo’s Ford Education Center. These young ladies were from Oakland County’s Children’s Village, a residential treatment and detention center for youth. The DZS began a partnership with Children’s Village in 2009 to instill respect and reverence for wildlife and wild places within the hearts of these teenagers. The program expanded in 2016 to offer off-site community service opportunities for the residents.

Mudpuppy shelters are an important piece of our ongoing conservation work as we monitor the population of these aquatic amphibians on the shorelines of the Detroit River and the inland lakes of Belle Isle. Mudpuppies are indicators of water quality; they cannot survive in polluted or contaminated water, so their presence is a sign of a healthy aquatic ecosystem.

DZS amphibian staff provided the specifications for the height, width and depth of these cement structures, as well as the materials to make them. The young ladies worked in pairs with DZS staff members, donning thick gloves and using wire cutters to trim heavy-duty wire mesh, before folding and binding it to form the bottom of the shelter. They then layered the cement over the wire mesh and built it into a solid, smooth floor and walls. Separate pieces of wire mesh were then cut to size and layered with the cement mixture to create roofs for the shelter.

Once the weather warms up, the shelters will be placed in the water around Belle Isle in hopes that mudpuppies will find them a desirable place to lay their eggs. They tend to lay their eggs under rocks in their natural habitat, which makes it difficult for researchers to locate the eggs without potentially disturbing them by having to move rocks. With the easy-to-remove roof on these homemade shelters, mudpuppies could lay their eggs inside and DZS staff would be able to lift the top and easily check on the eggs without disturbing them.

The young ladies who helped build the shelters will join us down on Belle Isle in the coming weeks to place them in the water. They will have the opportunity to work alongside DZS amphibian and education staff to record weather, water quality and shelter placement as well as check on previously placed shelters.

These teens are facing many challenges in their lives and working alongside scientists in the field offers them the chance to explore careers they may not have otherwise known about or considered. It is an opportunity for them to try a new experience, build skills and understanding, and give back to the community through conservation.

Claire Lannoye-Hall is a curator of education for the Detroit Zoological Society.

Habitat Expansions Benefit Animal Welfare

You may have noticed some changes at the Detroit Zoo recently, with construction occurring at many animal habitats. We recently unveiled the expansion of the Edward Mardigian Sr. River Otter Habitat, which tripled the outdoor space available to the North American river otters, complete with a flowing stream and a sandy beach. We’ve also been working on improving the giraffe habitat by adding much needed additional outdoor space and doubling the size of the indoor area. This past spring, Homer the Hoffman’s two-toed sloth moved to newly remodeled digs near the rhinos, and we’re currently renovating his former home in the National Amphibian Conservation Center to provide a more spacious habitat for the Japanese giant salamanders.

Sometimes, as was the case with the Polk Penguin Conservation Center and the Cotton Family Wolf Wilderness, we have the ability to design and build new habitats from the ground up. In other instances, we are able to take habitats that already contain many features that benefit the animals and expand upon them to provide even more space and complexity. In both situations, we begin with the knowledge we have about individual animals and how they interact with their environments.

For example, we know that otters are semi-aquatic. Staff at the Center for Zoo Animal Welfare have observed the animals engaged in a variety of water-related behaviors. When it came time to design the expansion of their habitat, it was very important that we incorporate features that would enable them to enjoy the water even more. It’s easy to see how much time they spend in the new stream, now making the most of both deep and shallow areas of water. And the island portion of the habitat enhances their opportunities to interact with various substrates and amplifies the overall complexity of their space.

As we move forward, we will continue to improve the habitats we provide for the animals that call the Detroit Zoo home, ensuring that they are stimulating and naturalistic. We are always a work in progress, keeping the welfare of the animals as our top priority. Up next are the tigers and several species of reptiles in the Holden Reptile Conservation Center. As we continue to learn about and understand the needs of the animals in our care – both the individuals and the species – we can make better choices that result in great spaces for them to live in.

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

Animal Welfare – Understanding the Needs of Amphibians

The penguins living at the Polk Penguin Conservation Center are not the only water-dependent species being studied by the Detroit Zoological Society’s Center for Zoo Animal Welfare (CZAW). We are conducting research to uncover indicators of welfare in frogs, toads and salamanders living at the Detroit Zoo’s National Amphibian Conservation Center.

Welfare indicators in amphibian species have largely consisted of body condition scoring and measures of reproductive success, neither of which provide comprehensive understanding of how individual animals are faring. Identifying additional indicators can help us to better understand the needs of amphibians living in zoos.

Due to the catastrophic declines in amphibian populations around the world in recent years, amphibian conservation has become a priority for zoos and other conservation organizations. While many institutions prioritize the management of captive populations of amphibians as one strategy in the preservation of these species, virtually no literature exists today regarding how the captive representatives of rapidly vanishing amphibians are faring. The Detroit Zoological Society created the National Amphibian Conservation Center nearly two decades ago, and it is still the largest facility dedicated to amphibian conservation and care in the world. CZAW is now conducting studies to help understand the individual preferences and behavioral and physiological responses of these animals to captive environments and husbandry practices, as well as individual capacities for coping with stressors of captive environments.

Housing animals in multi-species habitats is a common practice in zoos and aquariums. Some amphibians however, such as poison dart frog species, may be housed together due to their shared environmental requirements and their conspicuous aesthetics. Little research has been conducted on the impact that mixed-species living has on the welfare of the individuals. At CZAW, we have examined how different species partition their habitat and how their behavior may be impacted by one another. This helps us ensure that the needs of each animal are being met.

While much emphasis has been placed on the impacts of captivity on the welfare of large mammals, little attention has been granted to large amphibians living in the care of humans. Japanese giant salamanders are currently listed as Near Threatened by the International Union of Conservation of Nature and their wild numbers are decreasing due to habitat loss and hunting.

These salamanders present a unique challenge when it comes to habitat design, given their potential to grow up to 1.5 meters in length and their nocturnal activity patterns. Traditional ways of housing amphibians may not be as successful for giant salamanders and in turn may impact their welfare. The Immersion Gallery at the amphibian center is being renovated as a new habitat for the Japanese giant salamanders, with the goal of giving the animals increased physical and social choices. We are also developing a project to assess the ways in which this increase in choice can improve the welfare of the individual salamanders.

As we continue to study how amphibians can thrive in zoos, we not only help the individuals, but we can also contribute to the efforts being made to conserve them. Greater understanding of how individual captive amphibians are faring is critical to ensuring their well-being and to meeting ethical obligations of keeping animals in captivity.

Stephanie Allard, Ph.D., is the director of animal welfare for the Detroit Zoological Society and oversees the Center for Zoo Animal Welfare.

Take Part in the Detroit Zoo’s FrogWatch USA Conservation Program

By late winter and early spring, many people are looking forward to warmer weather, longer days and the fun the coming months will bring. I also look forward to this time of year, not only because of the warmer temperatures, but also the rains of spring and the wonderful creatures that will wake from their long, winter hibernation.

I am, of course, referring to frogs and toads! Here in southeast Michigan, most amphibians depend on rain to help them get “in the mood” for the breeding season. Soon after moving from deep winter to early spring, frogs and toads will make their presence known in full chorus, emitting sounds that also help to protect them from predators.

In 2011, the Detroit Zoological Society began hosting a local FrogWatch USA chapter to collect data on the frogs and toads living in the tri-county area. FrogWatch USA is an amphibian conservation and citizen science program managed by the Association of Zoos & Aquariums (AZA). Citizen science programs teach volunteers to collect data using the same protocol and methods, so all data can be can be counted as part of a scientific research project. One scientist working alone could never collect the amount of information a group of citizen scientists can.

There are currently 144 chapters of FrogWatch USA held throughout the U.S. and data has been collected since 1998. Training classes are primarily taught at AZA institutions, but may also be offered at nature centers, museums or colleges. The project focuses on frogs and toads – both amphibians and some of the most sensitive creatures on the planet. They are also indicators of a wetland’s health – if something toxic or lethal invades the wetlands where they live, they will be the first species to become sick, die or disappear.

All monitoring is done outdoors, so it gives volunteers the opportunity to spend time outside in the wetlands and natural areas of their community. Monitoring helps provide important information from each site, such as the diversity, population size and health of the particular frog or toad species that is present; whether or not there are rare or invasive species in the area, and what the overall health of the wetland is. Knowing what species are present at a sight can even help improve the management and protection of a wetland and all species living there.

Four-hour volunteer training sessions are offered at the Detroit Zoo just prior to the frog and toad breeding season, which is just about to begin. Each session includes:

  • An overview of what amphibians are and why they are valuable to the environment
  • Descriptions and key characteristics of the types of wetlands found in Michigan where frogs and toads may be found
  • Information about the locations of monitoring sites and the ability for participants to register
  • An explanation of the monitoring protocols that volunteers will use in the field
  • Information about how to identify the 14 native Michigan frog and toad species by their breeding calls (Identifying a species by its breeding call is by far the best part of the process. Even though it may be a bit challenging at first, surveying by ear is easy on both the surveyor and the frogs and toads, and it can be a lot of fun.)

Once training is complete, a volunteer’s first priority is to find and register for a site to monitor.  While most volunteers come in already knowing where they want to survey, some do not and we help them find locations in the area. Some sites are in backyards where frogs have been heard for years and others are in wetlands seen from afar and believed to be full of amphibians. Once the nighttime temperature is above 35 degrees Fahrenheit, volunteers can monitor at their sites throughout the FrogWatch season, typically February to August, at most twice a week.

Monitoring must take place at least 30 minutes after sunset. Darkness not only brings more amphibians to life but it also puts the noisy daytime animals, such as birds, to sleep. Whether volunteers have hiked into a wetland via a trail full of crunching leaves or are sitting on their back porch as quiet as can be, everyone must allow at least two minutes for the creatures around them to acclimate to their presence. Immediately after two minutes have passed, volunteers will listen for exactly three minutes to identify each species they hear. At the end of three minutes, the monitoring session is complete.

Monitoring the same site year after year is a great way to keep track of the health of frogs, toads and wetlands. If we lose amphibians, we lose a very precious resource and some really amazing creatures.

I hope you can attend one of the FrogWatch USA training sessions coming up at the end of this month, in February and in March. It is a fun and easy amphibian conservation program that anyone can take part in! Click here for more information: https://detroitzoo.org/press-release/leap-conservation-joining-frogwatch/

– Rebecca Johnson is the associate curator of amphibians for the Detroit Zoological Society and works in the National Amphibian Conservation Center.

Amphibian Conservation: Wyoming Toads Prepare for Breeding

A pair of small gold eyes peers out from under a mass of sphagnum moss. In a day or two, this warty creature will complete its climb out from the depths of the sandy soil where he has spent the last 30 days sleeping and “chilling” at a cool 38 degrees. Along with seven other individuals of this species, he will awaken due to an increase in temperature and light. By the time the temperature reaches 74 degrees, he will have completely removed himself from the soil and be sitting atop it, hopefully alongside his companion, a slightly larger female. In the week that follows, events these two small cold-blooded creatures will go through could lead to producing thousands of their species in a matter of hours due to their “explosive” nature.

The Wyoming toad (Anaxyrus baxteri) is one of North America’s most endangered species and one of the amphibians we work with as part of a Species Survival Plan (SSP) at the Detroit Zoo’s National Amphibian Conservation Center.  This toad’s wild populations began declining in the 1970s, and by the 1980s was listed as an Endangered Species by the International Union for the Conservation of Nature (IUCN). Possible causes for the population decline are use of aerial pesticides to eliminate mosquitoes, habitat manipulation, and disease in the form of the amphibian chytrid fungus. Realizing a decline was occurring, the last remaining toads were collected and by 1994, all remaining wild-born Wyoming toads were believed to be entirely in captivity. The IUCN now describes the Wyoming toad as extinct in the wild, meaning any toad currently found in the wild has come from captive breeding, in which the Detroit Zoological Society (DZS) has been actively involved.

The Wyoming toad SSP is managed by the Association of Zoos and Aquariums (AZA). The DZS has been a member of this conservation program since 1995 and since 2001 has sent a total of 6,505 tadpoles and toadlets to the wild. All Wyoming toads are the responsibility of the U.S. Fish and Wildlife Service (USFWS), so members of the AZA work closely with them to follow all USFWS permit guidelines for keeping them in captivity. The goal of any captive breeding program is to produce healthy offspring for release into the wild with the goal of rebuilding them into a self-sustaining population. Each toad in captivity is identified and tracked, which helps to pair toads that will produce the most genetically diverse and healthy offspring. Breeding pairs of toads are chosen almost a year in advance so toads have plenty of time to move from one zoo to another to create the breeding pairs.

Although not as well known as Jabari and Kivuli, the giraffe couple at the Detroit Zoo, Wyoming toads Butler and Beverly are a very important couple of toads. They are part of a “bio-secure” population and will never be seen by the public, which ensures they will not accidentally release diseases, known or unknown, into the wild via their offspring. They are held with four other pairs of Wyoming toads in a special room away from all other amphibians, so they will remain free of diseases that could otherwise be found in species not native to the western region of North America.

At the AZA’s recommendation, Butler arrived at the Detroit Zoo last October to be paired with Beverly, who arrived in 2012. Both are now 3 years old, which is about middle aged for a Wyoming toad. In early April, they were placed together into a thermostat-controlled “hibernaculum”, which is used to cool the toads, simulating the hibernation period a wild Wyoming toad would go through during the winter. The toads are kept cooled for about a month to help prepare them for breeding; eggs or sperms may develop and mature as a result of this cooling. The toads are given plenty of sandy soil to bury down into and sleep in just as they would have in the wild, and the Zoo’s animal care staff checks in on them weekly to make sure they are doing well.

At the end of May, the temperature in the hibernaculum will be increased to 70 degrees Fahrenheit and the toads will begin to awaken. Once they have climbed out from the soil, we will place them back into regular husbandry for a few days where they will continue to warm up and eat. Recordings of male toads calling are played during this time to condition toads further for breeding. Within a few days of emerging from hibernation, Butler and Beverly will be placed into a breeding chamber with 2-3 inches of water. The pair will hopefully go into “amplexus” within a few hours, which happens when the male positions himself on top of the female using his front legs and squeezes her, encouraging her to lay eggs. He fertilizes the eggs as she lays them, usually in the dark, overnight. Butler and Beverly should lay thousands of eggs, which is typical of toad species. Described as “explosive breeders”, the more eggs they can lay the better the chance offspring have of surviving the elements, diseases and predators. Since this is a captive breeding, we can help the thousands of eggs that Butler and Beverly produce survive into strong, healthy tadpoles.

Approximately two to three weeks after eggs have hatched into thousands of hungry tadpoles, arrangements are made with the USFWS to ship the tadpoles to Wyoming, where they will be released into protected wetlands. These tadpoles will add to those previously produced in captivity sent yearly by the zoos that participate in this program and the USFWS.

The wetlands are monitored during the spring and summer as part of yearly field surveys done to track the health and population of the toads. This year we hope that Butler, Beverly and the three other pairs of Wyoming toads at the Detroit Zoo are able to contribute thousands of healthy tadpoles to the wild population.

– Rebecca Johnson is the associate curator of amphibians for the Detroit Zoological Society.