Notes from the Field: Saving Tree Frogs in Honduras – Part II

As part of the Detroit Zoological Society’s (DZS’s) continuing efforts to save amphibians from extinction, we recently introduced readers of the DZS Blog to three species of endangered frogs that live in the Cusuco National Park in Honduras. These species are at high risk of extinction and we aim to help their populations. If you haven’t had a chance to read my previous blog entry, click here.

Amphibians are facing an extinction crisis, and one of the most tangible causes is disease. In my previous entry, I mentioned the chytrid fungus and how it is causing amphibian deaths globally. Many theories exist as to where chytrid originated and how it spread, but regardless of the answer to those questions, the fungus has now been found in almost every environment all over the world. Removing the fungus from the environment does not seem to be a possibility since it has become so widespread, as this could potentially damage the ecosystem and other lifeforms in it. So, the question becomes: How do we save the frogs?

Frogs are most susceptible to chytrid when they are young – tadpoles and juveniles have the highest death tolls as a result of this fungus. The tadpoles of the three target species we are focusing on in Honduras (the exquisite spike thumb frog, the Cusuco spike thumb frog, and the mossy red-eyed tree frog) are especially sensitive to chytrid. The tadpoles have very strong mouths, which they need to be able to use as a “suction” to hold onto rocks in rapid waters of rivers. Doing so is vital to their survival, and as such, chytrid is particularly damaging to these animals. Chytrid is attracted to keratinized skin cells, which are found in the mouths of tadpoles. The resulting infection causes them to lose function of their mouths, which can cause them to have trouble eating and difficulty with “suction” onto rocks. The loss of this suction can cause tadpoles to be swept downstream into unsafe waters.

Photo by Jon Kolby

This is all devastating; however, we came up with an idea for how we might be able to help.

What if we could remove tadpoles from the stresses of the environment during the stage in which they are most sensitive to chytrid? Using our skills and expertise in caring for amphibians, we might be able to nurture them in a pristine environment. The lack of stress would potentially prevent symptoms of the fungus from appearing. Alternatively, if symptoms did arise, caretakers could treat the fungus to assure survival. Then, when the animals have reached adulthood, they could be returned to the wild.

This method of rearing animals through sensitive stages is called “head-starting”, and is a method frequently used with amphibians. It has shown to be beneficial in instances just like this, where adults survive better than offspring. Long term, the hope is that the increased population from the head-started animals would be enough to booster the population into stability.

Photo by Jon Kolby

The Detroit Zoological Society and the Honduras Amphibian Rescue and Conservation Center are ready to start head-starting animals. Facilities have been built in Honduras in order to provide tadpoles a safe place to live and grow until they are ready for release. In an upcoming entry on the DZS Blog, we will go inside the rescue center’s facilities and show you what the tadpole rearing experience will look like!

– Dr. Ruth Marcec is the director of amphibians for the Detroit Zoological Society and oversees the National Amphibian Conservation Center at the Detroit Zoo.

Be Green by Eating Clean

There are many simple ways you can turn your lifestyle into a more environmentally friendly one, right down to the food you eat. But eating clean is about more than just buying and consuming fruits and vegetables. It’s about finding the food that is beneficial to both our bodies and the environment.

Take a look at some clean-eating tips:

  • Eat Local. Be the “locavore” that you know you are, by consuming food grown within a few miles of where you live. Locavores make frequent trips to farmers’ markets and purchase fresh produce within a local range. A great place for locavores in Michigan is Detroit’s Eastern Market, which is just 13 miles away from the Detroit Zoo. Other farmers markets are popping up all over the metro Detroit area including in Royal Oak, Birmingham, Clawson, Farmington, Grosse Pointe Park, Northville and Plymouth. Check your local websites for farmers’ markets near you. This simple change can not only lighten your carbon footprint because there are fewer miles for the food to travel and less gas being used to get there, creating less pollution on its way to your table. There’s also a reduction in greenhouse gas emissions during the production, packaging and transportation of your food, and it helps local farmers stay in business. There’s also something special about meeting the people who grow the food you put on your table.
    • Tips from a locavore:
      • BYOB (Bring your own bag). When visiting a farmers’ market or grocery store, bring your own reusable bags to cut down on the amount of plastic being used
      • Recycle any packaging that was on the foods you bought
      • Save gas by taking public transportation, a bike or carpool with family or friends
      • Make a genuine connection with the farmers whose produce you purchase
      • The produce at farmers’ markets are what is in season
      • If you’re buying non-organic, make sure to thoroughly wash your produce

  • Eat less meat: Try choosing veggies over meat; it’s healthier and you can help the planet. Perhaps try eating meat twice a week instead of four times, or even just once a week. Varying studies indicate the animal agriculture industry causes anywhere between nine and 51 percent of all greenhouse gas emissions. This means that by eating less meat, you can lower the amount of greenhouse gas emissions – and you can save water! Did you know that by skipping one burger, you can save enough water to shower with for three weeks? There are also health benefits to eating less meat, such as a lower risk of heart disease, stroke and diabetes, among others.

The Detroit Zoological Society is a leader in environmentally sustainability, with all operations guided by our award-winning Greenprint initiative. As part of our Green Journey, we are working to create a healthier environment for all animals, visitors and the planet. Offering options for visitors to eat clean at Zoo concessions is just one of the ways we’re working to create a more sustainable future.

The Detroit Zoo’s Pure Greens Café has a 100 percent vegan menu, offering items such as the “impossible burger”, made from simple ingredients in nature such as wheat protein, coconut oil, potato protein and heme. Visitors can also try our Mexican burrito bowl or vegan tofurky sausage. All of the vegetables come from Michigan farms, solidifying Pure Greens’ “locavore” status. Vegetarian and vegan options are also available at the Artic Café and American Coney Island, including a vegan burger basket, soups and salads.

Notes from the Field: Saving Tree Frogs in Honduras – Part I

The Detroit Zoological Society is collaborating with the Honduras Amphibian Rescue and Conservation Center to preserve three species of endangered frogs from the cloud forests of the Cusuco National Park in Honduras. The rescue center is an in-country facility that aims to re-populate these three endangered species through programs such as head starting, captive breeding, habitat protection and community outreach.

Amphibians all over the world are suffering extinctions, and the species in the Cusuco National Park are at a particularly high risk. There is a fungal disease, called chytrid, that is causing drastic population declines amphibians globally. Chytrid fungus has been particularly devastating to amphibians that live at higher elevations in the tropics, because the fungus thrives in lower temperatures and high humidity. This fungus likes to live in keratinized skin cells, and because amphibians rely on their skin to breath and exchange nutrients, it can be very deadly. The Cusuco National Park is a protected area that is home to many rare amphibian species who, unfortunately, are subjected to this fungal disease. The Detroit Zoological Society is working with the rescue center to investigate how to help save these animals from extinction.

While there are many species of amphibians in Honduras that need help, we decided to start our mission with three “target species” of critically endangered tree frogs. Once we find the best way to help these species, we can apply what we learned to others locally. These three target species are the exquisite spike thumbed frog (Plectrohyla exquisita), the Cusuco spike thumbed frog (Plectrohyla dasypus), and the mossy red eyed frog (Duellmanohyla soralia). All three of these frogs have been found to have the highest infection rates with chytrid fungus in the Cusuco National Park and are at high risk of extinction. This spring, we conducted fieldwork in Honduras, visiting the natural habitat of the three target species to help gain a better understanding of their behavior. We were able to observe some never-before-seen behaviors of these interesting animals that will help us increase our chances of protecting them.

Before I get too carried away, let me introduce you to the three species!

Photo by Jon Kolby

Exquisite spike thumb frogs are the largest tree frog in the Cusuco National Park at approximately 4 inches long. These frogs are found exclusively in the small protected area of the park, and are listed as Critically Endangered by IUCN. The frogs get their name from the large boney projection that males have on the sides of their thumbs, called a prepollex. It is theorized this special appendage is used for male combat, but combat has not yet been observed in this species. Additionally, the call of these frogs has never been heard (or at least recognized) by human ears.

Photo by Jon Kolby

Cusuco spike thumb frogs also only live in the small protected region of the Cusuco National Park; they are also listed as Critically Endangered. This species also gets its name from a prepollex in the males. Cusuco spike thumb frogs are medium-sized, growing to about 2 inches. Their call is a “quack” noise, similar to a duck. When threatened, these frogs have been observed jumping into leaf litter and burying themselves, which is unusual behavior for tree frogs.

Photo by Jon Kolby

Mossy red-eyed tree frogs are the smallest of the three target species, at a maximum of about 1.5 inches, and are also listed as Critically Endangered. As tadpoles, they have a striking green sheen to them, and they perform an odd behavior. They will flip over on their backs to swim – bellies up – in the rapids of waterfalls. Mossy red-eyed tree frogs can be heard calling with a series of chirps and clicks.

The Detroit Zoological Society and the Honduras Amphibian Rescue and Conservation Center have a plan to save these amazing animals. I’ll be sharing more details about this plan in upcoming blog entries, so stay tuned!

– Dr. Ruth Marcec is the director of amphibians for the Detroit Zoological Society and oversees the National Amphibian Conservation Center at the Detroit Zoo.

Animal Welfare: More than the “Bear” Necessities

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

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

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

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

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