Care Archives - Denver Zoo

Buy Tickets

September 19, 2023

Denver Zoo Announces AZA Accreditation

We’re thrilled to announce that Denver Zoo has achieved accreditation by the Association of Zoos & Aquariums (AZA). This prestigious accreditation reflects our unwavering commitment to animal care, wildlife conservation, education, science, and recreation. We’ve undergone an extensive and comprehensive evaluation of our operations and programs, resulting in a well-deserved five-year accreditation. This reaffirms our position as one of the top zoos in North America and a leader in animal care and conservation. Denver Zoo has maintained its status as an AZA-accredited facility since it was first accredited in 1976.

“AZA accreditation is the ultimate stamp of approval for our profession, and assures our guests and members that we’re providing the best possible care for our animals and creating a safe, enjoyable experience for our community. We’re beyond proud to be among the very few zoos and aquariums in the world that maintains such a high standard across our programs and operations.”

Bert Vescolani, President & CEO of Denver Zoo.

It’s worth noting that fewer than 10 percent of the 2,800 wildlife exhibitors licensed by the United States Department of Agriculture (USDA) under the Animal Welfare Act meet the comprehensive standards of AZA accreditation. As an accredited organization, we’re subject to evaluation every five years by a team of expert inspectors who assess animal welfare, care, and management, including living environments, social groupings, health, and nutrition. They also evaluate all other aspects of our operations, from our involvement in wildlife conservation and research to our guest services, education programs, and finances.

We believe this accreditation process is of utmost importance. Every year, AZA sends over 200 accreditation inspectors worldwide to review applications, and we have nearly 40 facilities participating in our Pathway Toward Membership program, reflecting the growing significance of independent accreditation. AZA’s standards are continually updated to incorporate cutting-edge zoological practices based on the latest animal well-being science and research, attracting the best-of-the-best zoos and aquariums to be part of our association.

In addition to our AZA accreditation, Denver Zoo earned the American Humane Certified™ seal in 2020 for our exceptional treatment of the animals in our care. This achievement, similar to an AZA inspection, required us to pass rigorous, expert third-party audits. We join a distinguished group of leading zoological institutions that have received the American Humane Certified™ designation.

Buy Tickets

May 11, 2023

Rowdy Research

By Maura Davis, Curator of Large Mammals

“Where are your females?”

“Why don’t you have babies?”

These are among the most common questions we get at Denver Zoo about our Asian elephant herd, and while our answer isn’t always what a guest is looking for (we don’t house females, so no babies here!), the way we take care of elephants in Toyota Elephant Passage is part of a larger goal to better understand male elephant socialization in the wild, and in human care.

Toyota Elephant Passage opened at Denver Zoo in 2012 and was specifically designed to hold bulls. In 2016, we started socializing male Asian elephants and our team of elephant care specialists dedicated their time to learning as much about the integration process and consequences of those interactions as possible. Many zoological institutions that are housing male elephants often experience difficulties in socializing them as they get older due to numerous changes that occur as they mature, the most significant being their annual hormonal cycle called musth.

The social structure of the herd in Denver was specifically designed to have a mature male (Groucho, age 53), who can teach and lead with patience and appropriate dominance, and a range of younger bulls who recently left their family groups to come and learn from Groucho’s teaching. As these younger males mature, they could be recommended to move elsewhere to a breeding institution to continue working with the Association of Zoos and Aquariums’ Species Survival Plans efforts to keep genetic diversity within the AZA’s Asian elephant population. As more male elephants are born, there will be a growing need for other institutions to house multiple male elephants, so learning best management practices and the importance of social hierarchy are important to set those other facilities up for success in the future.

Denver Zoo has been working with researchers over the last several years to study multiple aspects of male management, and recently published a study titled “Age and Social History Impact Social Interaction Between Bull Asian Elephants at Denver Zoo.” In this study, we found that behavior significantly changed when the mature male was present and that including at least one mature male in social groupings may reduce competition between adolescents. This has helped us understand how to best set up introductions of new elephants into our herd by starting with the the most mature male to help guide appropriate interactions when a new bull is establishing himself in the group.

While this research helps us understand our own herd better, it will also be used worldwide to support the care of elephants in their native ranges, and in other accredited institutions. In India, the research is able to help guide governmental policy regarding the removal of adult males from groups of younger males in wild herds. Young males without the guidance of an adult bull show more tendencies to raid crops and cause damage in populated areas.

We were able to see this research in practice with the arrival of our newest juvenile, Duncan. Duncan has only been at Denver Zoo for two weeks, but is already acclimating well with members of our herd, thanks to the work of our elephant care specialists. He spent his first day with Groucho to ensure Duncan had the mature male as support to help guide appropriate introductions to the younger elephants. He has since met 14-year-old Chuck and 13-year-old Jake while under Groucho’s guidance. Our animal care specialists will continue to introduce him to other members of the group as he settles in.

Research is a time-consuming process, but the insights gained, and the ability to share them with other organizations caring for Asian elephants, are invaluable. And thanks to our dedicated team, we now know more about male Asian elephant socialization than we ever have.

Buy Tickets

February 25, 2022

New Flamingo Habitat Coming Soon

Our Chilean and American flamingos are about to get a new home! With topography inspired by the Andean highlands, the new habitat will provide both the flamingos and their fans year-round access to both indoor and outdoor living spaces-including multiple wading pools, nesting islands and multiple vantage points for viewing our most fabulous flock. Construction will begin this winter, with the grand public opening slated for 2023.

Flockstars at Denver Zoo

With rock star names (and personalities to go with them), our flamingos are fan favorites at the Zoo, and the leading ladies and gentlemen of one of our most popular Up-Close Looks. Our Chilean flamingos are much lighter in color, and can be found in the Andean highland regions of Chile, Argentina, Peru and even Brazil. While our American flamingos have bright, pinkish-orange feathers, and are often found in coastal areas of the Caribbean including the Bahamas, Cuba, and the Yucatan Peninsula. In 2018, we welcomed two male Chilean flamingo chicks, Swift and Legend. And in late 2021, we welcomed three more with the addition of Jonas, Denver and Diamond-who all hatched and were hand-raised at our Avian Propagation Center to give these fragile birds the best chance of survival. Two-year-olds Swift and Legend are fully integrated with the flock, while our youngest chicks, Jonas, Denver and Diamond join them for walks when the weather allows.

Flocking to Help

Flamingos aren’t just a species we care for here at the Zoo. We also work to save flamingos abroad, including taking part in an international effort to rescue more than 1,800 abandoned lesser flamingos in South Africa in 2019. Using their skills and background knowledge of working with flamingos, two of our bird keepers and a veterinarian technician were able to rehabilitate and eventually release many of the rescued flamingos back into their native range.

Spreading Our Wings

We’re excited to open a new habitat for our flamingos next Spring. Construction starts this winter, so pardon our dust on your next visit. Follow us on Facebook, Instagram, Twitter and TikTok for more updates about the flock and their new home!

Buy Tickets

October 8, 2021

Good Hope for African Penguins

If you happened to miss the noisy brays of excitement-both ours and the birds’-Denver Zoo’s waddle of 17 African penguins got some deluxe new digs last month. On September 30, after about a month of private penguin acclimation, Pinnacol African Penguin Point opened to great public fanfare.

With a clear 10,000-gallon swimming pool surrounded by heated rockwork and fitted with cozy burrows, Penguin Point was indeed inspired by the distinctive landscapes of the species’ hometown habitat. But there’s more to this tuxedo-clad tale than just topography. Read on to learn more about the unexpected conservation success story of Boulders Beach, how Denver Zoo is involved…and what YOU can do.

The African Penguin: A Species’ Deadly Demise

The African penguin (Spheniscus demersus) lives exclusively in the warm waters of coastal Southern Africa, from Namibia to Port Elizabeth, including many of the surrounding islands. The birds are social breeders, nesting in colonies like the one at Boulders Beach-a quiet coastal community which has unwittingly become one of Cape Town’s most beloved tourist attractions.

But over the past 100 years, wild African penguin populations across the South African coast have declined more than 98%-from more than a million breeding pairs to just about 25,000 pairs. Overfishing, plastic pollution, climate change, habitat encroachment and oil spills are all significant contributing factors. The species was first classified as endangered by the Union for the Conservation of Nature and Natural Resources (IUCN) in 2010. But by 1983, the colony at Boulder’s Beach had already been reduced to just two breeding pairs.

Travis Garrett (Denver Zoo) and Aimee Sugrue (Mystic Aquarium) hand-feed sardines to African penguin chicks

Many of the remaining wild African penguin colonies live within coastal nature preserves or on small, protected islands mostly uninhabited by humans-which removes at least one of the stressors mentioned above. But Boulders Beach is in a bustling suburb of Cape Town, South Africa’s second-largest city. And, since it’s the only place in the world where humans can get close to these charismatic class clowns, Boulder’s Beach experiences a population boost of 60,000 every year, from penguin tourism alone.

Reduced Fishing. When the Boulders Beach colony was established in the early 1980s, the most serious threat to local penguin populations was commercial fishing in False Bay. As the area’s natural supply of anchovy and pilchard dwindled, the penguins had to swim farther and farther to find food. And, since penguin pairs take turns fishing and minding their nests, these extended absences left mates, eggs and offspring dangerously vulnerable to predation, dehydration and starvation. Government-mandated reductions in pelagic trawling helped the food supply-and the penguins-to start bouncing back.

Penguin Rehabilitation. Here at Denver Zoo, penguin conservation gets personal! Every year, we send our resident penguin experts, Travis Garrett and Stephanie Hollister, to Cape Town-where the Southern African Foundation for the Conservation of Coastal Birds (SANCCOB) works tirelessly to rehabilitate and release penguin chicks. Travis and Stephanie volunteered alongside SANCCOB’s full-time staff, fellow AZA program participants and zookeepers from around the world to rescue and rehabilitate chicks that would not otherwise survive, then release them back to the Boulders Beach and Stony Point colonies. To date, SANCCOB partnerships like this one have led to the release of nearly 90,000 penguin chicks.

Stephanie after releasing rehabilitated penguins to the resident African penguin colony at Boulders Beach

Species Survival Plan. Thorough our accreditation by the Association of Zoos and Aquariums (AZA), Denver Zoo participates in the Species Survival Plan (SSP) for many species, including the endangered African penguin. This cooperative program facilitates collaboration among zoos around the world, with the goal of ensuring healthy genetic diversity in zoo animals under human care-as well as the breeding of assurance populations to bolster species for whom wild populations are in decline.

Protected Parkland. In 2004, the coast surrounding Cape Town became Table Mountain National Park Marine Protected Area, dedicated to preserving the two distinct marine bioregions that fall to the east and west of the Cape of Good Hope. In addition to African penguin colonies at Boulders Beach and Stony Point, the area is known for its robust shark and whale populations and is a haven of biodiversity. The goal of the “protected” designation is to set sustainable guardrails for tourism, allowing people to enjoy the area while supporting the healthy growth of vulnerable and endangered marine species.

Responsible Tourism. Tourism, as you might imagine, is a double-edged sword at Boulders Beach; it simultaneously raises public awareness about the challenges African penguins are facing, while potentially contributing to those challenges. But in the decades since the national park designation and IUCN classification, other entities have championed the penguins’ cause in other ways. Strict systems and regulations are in place to protect the colony; an elevated boardwalk also allows visitors to view the colony from a safe distance, while eco-safari tents enable low-impact overnights for penguin superfans.

It Takes a Village to Heal the Planet

As a zoo-based conservation organization, we understand that much of our global impact starts at the local level. That’s why the design of a wildlife experience like Pinnacol African Penguin Point is about so much more than viewing windows or an interactive wavemaker-although those things are pretty cool, too. There’s century-old conservation success story behind Penguin Point. It’s one we hope will inspire our guests to consider the world’s wildlife as they move about their lives. So, what can YOU do?

1. Support Denver Zoo. Every donation, membership and ticket helps us care for our 3,000 animals. Your visit also helps fund critical conservation efforts around the world, including our partnership with SANCCOB-which we’re thrilled to be supporting again this year.

2. Choose Seafood Wisely. Our partner, Monterey Bay Aquarium, makes it easy to choose seafood that is responsibly sourced. Add Seafood Watch® to your home screen today to ensure that your meals don’t contribute to wildlife endangerment.

3. Avoid Single-Use Plastics. With single-use plastics, recycling is no longer enough; it’s a much better choice to avoid them altogether. Coffee cups, drinking straws, yogurt tubs, shampoo bottles-consider everything in your grocery cart and ask yourself if there’s a better option.

4. Adopt a Penguin. If this article hasn’t made you feel like hugging a penguin…are you okay? One surefire way to start feeling FINE is to snuggle up with a formal feathered friend-the plush version, that is! It’s a great way to show your love for penguins and get a special souvenir of your visit.

Buy Tickets

April 24, 2020

One World, One Health

Kerry Owens, Certified Veterinary Technician

A passion for animal health and saving endangered species led me to Denver Zoo more than a decade ago. And I didn’t want to limit my work to just the animals that call Denver Zoo home. But how can one Certified Veterinary Technician (CVT) have an impact on a species that lives on the other side of the world? By approaching animal health with a concept known as One Health-an understanding that the three pillars of animal health, ecosystems, and human health are inseparable. You cannot save endangered species without saving their ecosystems. You cannot save ecosystems without people. You cannot have healthy people without healthy ecosystems. You cannot have the health of one without the other.

Why One Health

The term One Health was coined back in 2004, and is now supported by institutions like the World Health Organization (WHO), the Centers for Disease Control and Prevention (CDC) and the American Veterinary Medical Association. And One Health is used right here at Denver Zoo. When we treat an animal, we’re not just looking at the individual, we’re considering those three factors – animal health, human health and ecosystem health.

Putting it All Together

My day-to-day routine at the zooincludes everything from vaccinating zebras to using medical laser treatments on hyenas, but I’m able to put some of that One Health training to use when I step away from Denver Zoo and in threatened ecosystems. I’ve assisted the Denver Zoo field conservation team by restoring watersheds at the Rio Mora National Wildlife Refuge in New Mexico and supported our work at the Ikh Nart Nature Reserve in Mongolia, where I conduct health assessments on vultures. These raptors are a great example of why One Health matters. Vultures keep ecosystems clean and free of diseases by eating carcasses. Their ultra-acidic stomach acids kill the pathogens found in the carcasses, thus cleaning ecosystems up for animals and humans. Healthy vultures keep all kinds of other creatures from getting sick. But my work in Mongolia and New Mexico has been about more than animal health. One Health means I’m monitoring water tables, working with livestock owners and sheep herders to implement responsible practices and restoring vegetation where needed. All of these things contribute to a healthy ecosystem, one that gives animals and people a home, healthy air, clean water and edible food.

Everyone Has a Role

One Health can seem like an overwhelming idea, but it’s also quite simple-we’re all connected. We use this philosophy at Denver Zoo to help the animals in our care, and to help threatened and endangered species, but you don’t have to be a CVT, zookeeper or conservationist to practice One Health. Take a moment to think of the ways the three pillars of One Health are connected in your life. Do you have plants in your backyard? What species do they support? Do you buy products that are sustainably sourced and helping maintain habitats for animals in the rainforests? The more you think about One Health, the more opportunities you’ll find to practice it in your daily life, and the more you’ll see just how connected we really are.

Buy Tickets

March 31, 2020

Accreditation is Everything

By Brian Aucone, Senior Vice President of Animal Sciences

There are nearly 2,300 “zoos” across the United States, but not all of them are created equal. That reality has once again been brought to the forefront with the recent release of the Netflix docuseries, Tiger King: Murder, Mayhem and Madness, which delves into the underworld of big cat breeding and some of its most infamous characters. The people and places featured in the show are notorious for housing animals in appalling conditions, mismanaging breeding for profit, and perpetuating the black-market wild animal trade and animal cruelty. Only 10 percent of zoos in the U.S.-238 to be exact-are accredited by the Association of Zoos and Aquariums, which holds its member zoos to the highest standards of physical and mental care for wildlife-standards that are unachievable for the vast majority of other zoos. That means when you visit Denver Zoo and our AZA counterparts around the country, you can rest assured that you are supporting an accredited organization that provides excellent care to its animals and helps save wildlife around the globe. Here are a few key differentiators between Denver Zoo and other “zoos,” and why you should support AZA-accredited organizations, now more than ever:

We have an expert animal care staff that includes nutritionists, behaviorists, caretakers, animal welfare specialists, veterinarians and veterinary technicians, who are all focused on providing the absolute best care to every single one of our nearly 3,000 animals. We are among the most qualified wildlife care experts in the world.
We work around the globe to help save wildlife and wild places in countries like Mongolia and Peru, and even here in our own back yard of Colorado. Working with local communities, to understand their needs living alongside wildlife, together we solve complex issues that benefit people and animals. Our expertise and partnerships have created meaningful and lasting conservation impact for thousands of species.
We create meaningful connections to wildlife for the millions of guests who walk through our campus. Many of these individuals would never have the opportunity to see wildlife in person, and seeing animals in-person remains the most impactful way to create empathy. We are the window into the wonders of the wild world.
We participate in national and international breeding programs, called Species Survival Plans, that ensure a future for the magnificent wildlife in our care. Without these breeding programs, species like the black footed ferret, Panamanian golden frog, and California condor would most likely be extinct.
We reach tens of thousands of children around Colorado through our conservation education programs, teaching them the wonders of wildlife and how they can help. On our campus, we reach millions of guests through our comprehensive conservation messaging and educational programming. No one else in Colorado is doing this at our scale.
We were the first zoo to receive the AZA’s Green Award, which recognizes the efforts of zoos and aquariums take to reduce their environmental impact, and we continue to strive to operate in the most environmentally, socially and economically friendly way possible.

When you visit Denver Zoo and other AZA-accredited facilities, you are making a positive impact on the thousands of animals in our care and their wild counterparts around the world. We look forward to welcoming you back to the Zoo in the near future, and greatly appreciate any donations to our Emergency Support Fund that help us offset the cost of caring for animals during our closure due to COVID-19.

Buy Tickets

February 19, 2020

Supporting the Gorilla SSP

Denver Zoo works collaboratively with other organizations accredited by the Association of Zoos and Aquariums to support Species Survival Plans (SSP)-breeding programs that ensure healthy, genetically-diverse populations of nearly 500 mostly threatened and endangered species. This important effort means we often move animals to other zoos to be paired with new mates, or live in a facility that is best suited for their needs and stage in life.

In support of the Gorilla SSP, we will soon welcome a new troop of Western lowland gorillas from another AZA-accredited zoo. These three males, who are too old to stay with their family unit, will form an all-male troop until they can find a family group of their own-just as they would do in the wild. This can be a challenging situation for some zoos, however our Great Apes habitat combined with our staff experience and expertise will allow us to provide exceptional care for the new bachelor group. They are currently scheduled to arrive in early spring.

In the meantime, to accommodate the incoming troop, both of our resident bachelors, Charlie, 23, and Curtis, 24, will move to Kansas City Zoo in March. While we’ll miss Charlie and Curtis, we’re excited for their new adventure, and for our community to make connections with a new bachelor group and learn more about the species and how they can help. Guests are encouraged to visit and wish them farewell before they move to their new home.

Western lowland gorillas are listed as critically endangered by the International Union for the Conservation of Nature. Their primary threats include logging, agriculture and poaching through their native ranges in Nigeria, Cameroon, Central African Republic, Equatorial Guinea, Gabon and Congo. AZA-accredited zoos help the species through the Gorilla SSP, which is an increasingly important insurance policy for the species as wild populations decline in the face of mounting threats, and countless other animals by contributing more than $231 million in support of conservation projects every year.

Be sure to follow us on Facebook, Twitter and Instagram for the most up-to-date information about our incoming group of gorillas and the rest of the 3,000 animals that call Denver Zoo home!

Buy Tickets

August 15, 2019

If You Musth Know

By Maura Davis, Elephant Care Expert

If you come to Toyota Elephant Passage, you might see anywhere from one to five of our Asian male elephants together in a given yard. Jake and Chuck might be sparring in one yard while Billy and Bodhi forage in another. Every day brings a new combination for our boys, which is just as fun for their care team to watch as it is for them to socialize. As amazing as it is to watch these boys interact, socializing Asian bull (male) elephants is relatively new, and we’re learning more and more about the intricate social dynamics of this animal every day.

Three’s Company

In December of 2016, two years before we welcomed Jake and Chuck, the Toyota Elephant Passage care team started the process of developing a bachelor group. We worked with Billy (8 years old at the time) and Bodhi (12 years old at the time) to become the first two introduced to one another. We were pleased to see how their relationship blossomed and decided to add another bull to the mix. Just a few short weeks later Groucho (46 years old at the time) joined the group under the watchful eye of nearly every person on the elephant care team. All the boys got along great, and we officially had North America’s largest bachelor herd of elephants. At his age and size, Groucho was a natural leader and the dominant bull in the herd. Billy and Bodhi never challenged him and always were submissive when he was around. But the elephant team noticed a big change in the spring of 2017. Billy, our youngest bull, was pushing Groucho around in an aggressive way. This was very unusual behavior that we had not seen from Billy before, especially towards Groucho, and the team worked quickly to separate the group and determine what might have caused this dramatic change in behavior. After careful examination of his behavior over the next couple of days, it was determined that Billy was maturing and had come into his first musth.

What’s Musth?

Musth is an annual hormonal cycle that naturally occurs in adult male elephants. Their testosterone increases significantly, it has huge impacts on their behavior and they exhibit some physiological changes including draining from their temporal gland on the side of their face as well as continuous urine dribbling down their back legs. Musth is a large part of a male elephant’s life but a lot is still unknown about this cycle. Male Asian elephants are difficult to study in Asia since there are few of them and when they are in musth, they become more aggressive and incredibly dangerous to be around. But here at Denver Zoo, our bulls still participate in training sessions when they’re in musth – which creates an opportunity to learn more about this complicated hormonal cycle. Denver Zoo is participating in a study with researchers Wendy Kiso and Chase LaDue to study musth. This study not only includes male elephants in zoological settings across the United States but also includes male elephants in Sri Lanka.

Bulls: Bullied or Bullies?

Human elephant conflict is a leading cause of elephant population declines Southeast Asia. As human populations grow and the boundary between wild elephants gets smaller and smaller, it’s important for us to understand how musth plays a role in an elephant’s behavior. Musth males often turn towards nutritionally rich foods which typically result in finding their food in human crops. With elevated testosterone levels, those male elephants can be far more aggressive. In Sri Lanka, 70 humans and 235 elephants are dying annually due to human-elephant conflict. Having a better understanding of how musth impacts male elephants’ behavior can give us more information to help environmental management strategies in Asia.

“Elephants in zoos are valuable sources of information for researchers…we can conduct behavioral observations and collect a variety of biological samples with voluntary participation from the elephants. All of this is virtually impossible to do in the field where logistics prevent researchers from following and or approaching elephants. What we learn from elephants in zoos helps us better understand how to study, manage and conserve elephants in the wild,” says LaDue.

Handling the Herd

In June of 2019, more than two years after his first musth, Billy completed his third annual cycle and we now know what to look for in Billy’s behavior that would indicate to us that this hormonal change is occurring. This allows us to set up our herd’s socialization periods appropriately so none of the males are in a situation where there is risk of musth aggression. We have been able to proactively provide an environment where all the males can safely continue to socialize and interact with one another while also accommodating this unique time in a male elephant’s year.

So, the next time you see our five boys at Toyota Elephant Passage, take a minute to appreciate how their interactions are helping people on the other side of the world co-exist with wild Asian elephants! And make sure you stop by one of our daily elephant demonstrations to learn how you can help this endangered species.

Buy Tickets

June 27, 2019

A Toad-al Success

Amphibians are facing an unprecedented crisis. More than 50 percent of frog, toad, salamander and caecilian species are at risk of extinction within the next 50 to 100 years due to habitat loss, climate change, pollution and disease. Chytrid fungus, in particular, can infect the majority of the world’s more than 7,000 amphibian species, and is linked to overwhelming population declines and extinctions globally.

One of those affected species lives in our own backyard. The boreal toad, which is found in high-altitude habitats between 7,000 and 12,000 feet in the southern Rocky Mountains, is listed an endangered in Colorado and New Mexico, and protected in Wyoming. With its numbers in severe decline over the past two decades, many government agencies and zoos, including Denver Zoo, Utah’s Hogle Zoo, Omaha’s Henry Doorly Zoo and Aquarium and the Living Planet Aquarium, have stepped in to support the species through research and breeding programs aimed at boosting wild populations. Success has been relatively limited…until now.

On June 3, Denver Zoo amphibian experts Tom Weaver and Derek Cossaboon, and staff member Judy Mead, traveled to a remote area of the Paunsaugunt (pronounced “PAWN-suh-gant) Plateau in southwestern Utah to release more than 620 toads, which had been hatched and raised at the Zoo, into their native range. The successful breeding and release of this magnitude is a boon to the population of these high-altitude amphibians and future efforts to save the endangered species from extinction.

“As zoologists, it’s incredibly important that we apply our passion for wildlife to the animals in our care and leverage our expertise to help wild populations,” said Weaver. “This initiative really connects what we do here at the Zoo with our ongoing efforts to save wild animals, and serves as a testament to the collective expertise we share with other zoos and partners. It’s a career high.”

But success did not come quickly or easily. It took years of work, many experts and shifts in our approach. Read on below to learn about our journey to reach this point:

Breeding Barriers

In 2011, the Utah Division of Wildlife Resources sent small groups of boreal toad “assurance populations” to Denver Zoo and other institutions. We cared for the animals for behind the scenes until they were mature enough to start breeding. In 2016, Weaver and Cossaboon attempted to get the toads to breed by simulating hibernation, but neither of the female toads produced eggs. Several other institutions, including Henry Doorly Zoo and Aquarium, Hogle Zoo and Loveland Living Planet Aquarium, experienced similar struggles breeding their assurance populations.

Third Time’s the Charm

In 2019, our on-staff research manager and reproductive specialist, Dr. Anneke Moresco, got involved to develop a new breeding plan after two failed attempts. She implemented a new hormone protocol from Detroit Zoo, and Cossaboon adjusted their hibernation parameters, lowering the temperature down to just above freezing. As a result, soon after they came out of hibernation in early April, the females laid an estimated 1,000 eggs. Over the next eight weeks, more than 600 eggs hatched into tadpoles and started metamorphosizing into young toads. When the toads were mature enough, Dr. Scott Larsen tested the toads for chytrid and visually examined them to make sure they were healthy for travel and release (yes, they got a health certificate). Once ready, Weaver and Cossaboon carefully prepared them for transport for release in Utah.

An Amphibian Adieu

With the help of the U.S. Forest Service, Hogle Zoo and the Utah Division of Wildlife Resources, all the toads were released on June 3. It had been an unusually cold spring, and the night of the release, a deep frost set in over the site. The toads were released that morning, and over the next few days, were observed eating and moving as far as 75 feet away from their release point-quite a distance to travel when you’re only an inch long!

All for One, One for All

News of the release spread quickly throughout the conservation community, and other facilities started reaching out wanting to know how we did it. We meticulously documented every step in the process it took to successfully breed the toads, from the specific hormone protocol, the water temperatures to what we fed the tadpoles, in the hopes that we and other institutions can replicate our success for boreal toads-and other amphibian species-in the future.

Buy Tickets

May 6, 2019

Banking on Success

By Stephanie Hinkle, Certified Veterinary Technician

When Dobby the reticulated giraffe was born in 2017, he faced life-threatening health issues. He wasn’t nursing enough, so he wasn’t getting vital antibodies, which put him at a high risk for infection and possibly death. But a plasma transfusion, with plasma from a Cheyenne Mountain Zoo giraffe, saved Dobby’s life. That same year, another plasma transfusion, with plasma from a Columbus Zoo okapi, saved our baby okapi Forest. Dobby’s and Forest’s stories are just a few of the successes that can be attributed to plasma and blood banking. And in the last few years, our veterinary medicine team has spent more time banking plasma and blood from the animals in our care, so that we can help the animals at our zoo and other institutions around the country.

Why Plasma?

Dobby and Forest benefited from the antibodies found in plasma, but plasma itself has many other uses. Plasma is the liquid portion of blood that carries cells and proteins throughout the body. In our Asian elephants, plasma transfusions can be crucial for treating a deadly virus called elephant endotheliotropic herpesvirus (EEHV), so it’s necessary that we have plasma on-hand to treat our elephants or share with other zoos if needed.

Trial and Error

One of the first animals we tried plasma banking with was Rudy, our 25-year-old black rhino. Rudy has iron storage disease, and one treatment for his condition is to collect nearly three liters of blood over the course of three weeks. In addition to helping lower his iron levels, it also gives us the opportunity to collect plasma during his treatments. Even though Rudy is already trained to participate in his own medical care, the vet tech team and his keepers had to try a few different techniques to collect enough blood in each session.

At first, gravity was not our friend. We collect blood at Rudy’s “wrists,” which are very close to the ground. That meant there was no way to get the bag low enough to collect more than a few milliliters of blood at a time. We switched to a different method, which helped us collect 250-500 mL, but that still required several sessions to get the desired amount of blood. We continued to use the technique for several months until I went to a conference at Columbus Zoo, where I was able to learn from other vet techs who had a technique that allowed them to collect up to a liter of blood in one session. We tried it with Rudy and collected a full liter in his first session!

Like Rudy, Groucho, our 50-year-old male Asian elephant, is also trained to work with keepers and participate in his medical care. Using the same technique we applied to Rudy’s collection, we went from collecting 500 mL of blood per session, to getting a whole liter of blood, which means more plasma to bank for our elephant herd. The vet tech team also works closely with the keepers at Toyota Elephant Passage to monitor for signs of EEHV in all our elephants.

Your Support

With a commitment to being a leader in animal care, Denver Zoo decided it was time to purchase our own plasma transfusion equipment. Not only is on-hand plasma vital to the health and longevity of animals here at Denver Zoo, but it will enable us to provide emergency transfusions to animals around the country.

Collectively, our donors have contributed more than $32,000 to purchase the plasma transfusion equipment. Your generosity will give us the power to perform instantaneous and life-saving transfusions for the animals that call Denver Zoo home.

Thank you for your commitment to Denver Zoo. From Dobby, Forest, Rudy, Groucho and many more, we are grateful for you.

Stories Like This

ANOTHER TOAD-AL SUCCESS

How Denver Zoo Conservation Alliance Helps Keeps our Anim...

A Pink Tie Affair

By Maura Davis, Curator of Large Mammals

Stories Like This

ANOTHER TOAD-AL SUCCESS

How Denver Zoo Conservation Alliance Helps Keeps our Anim...

A Pink Tie Affair

Flockstars at Denver Zoo

Flocking to Help

Spreading Our Wings

Stories Like This

ANOTHER TOAD-AL SUCCESS

How Denver Zoo Conservation Alliance Helps Keeps our Anim...

A Pink Tie Affair

The African Penguin: A Species’ Deadly Demise

It Takes a Village to Heal the Planet

Stories Like This

ANOTHER TOAD-AL SUCCESS

Meet the Flockers

Endangered Frogs Bounce Back

Kerry Owens, Certified Veterinary Technician

Why One Health

Putting it All Together

Everyone Has a Role

Stories Like This

ANOTHER TOAD-AL SUCCESS

African Impact

Meet the Flockers

By Brian Aucone, Senior Vice President of Animal Sciences

Stories Like This

ANOTHER TOAD-AL SUCCESS

African Impact

Meet the Flockers

Stories Like This

ANOTHER TOAD-AL SUCCESS

African Impact

Meet the Flockers

By Maura Davis, Elephant Care Expert

Three’s Company

What’s Musth?

Bulls: Bullied or Bullies?

Handling the Herd

Stories Like This

ANOTHER TOAD-AL SUCCESS

African Impact

Meet the Flockers

Breeding Barriers

Third Time’s the Charm

An Amphibian Adieu

All for One, One for All

Stories Like This

ANOTHER TOAD-AL SUCCESS

African Impact

Meet the Flockers

By Stephanie Hinkle, Certified Veterinary Technician

Why Plasma?

Trial and Error

Your Support

Stories Like This

African Impact

Meet the Flockers

One World, One Health