The Denver Zoo started in 1896 with a single bear in City Park and has grown to an eighty-acre campus. There are 350 employees overseeing a total of about 3,700 animals from more than 600 species. The zoo draws more than 2 million visitors per year, making it one of Colorado’s most popular cultural attractions.
During its early decades, the Denver Zoo was run by the Denver Parks Department. Apart from the 1918 development of Bear Mountain, usually regarded as the first naturalistic exhibit in the United States, the zoo had a low budget and emphasized entertainment. That changed after World War II, when the Denver Zoological Foundation took over management and fundraising. The zoo became more professional, with a greater focus on education and conservation, especially under longtime board chair Helen Johnson (1957–78) and director Clayton Freiheit (1970–2007). Today innovative exhibits such as Predator Ridge (2004) and Elephant Passage (2012) have placed it in the forefront of zoo design.
In the late nineteenth century, the large-scale killing of wild animals—particularly large predators such as lions, tigers, and bears—made collections of such animals for conservation and public exhibition seem valuable and interesting. This was especially true in the American West, where large herds of bison and other animals rapidly gave way to railroads and cities. Some of the earliest zoological gardens in Denver were private animal collections, including Mary Elitch’s popular zoo at Elitch Gardens (the first woman-run zoo in the world) and Manhattan Beach’s small collection on the north shore of Sloan’s Lake.
At the same time, cities were starting to develop their own municipal zoos, which were often located in large public parks and linked to nearby botanical gardens and natural history museums. The Denver Zoo emerged as part of this movement, though its origins and early decades were largely unplanned. The zoo’s first animal was Billy Bear, a black bear captured on the Western Slope in 1896 and sent by rail to the general passenger agent of the Colorado Midland Railway, who was a friend of the hunter. The passenger agent did not want a pet bear and promptly gave it to the Denver Board of Park Commissioners, who tied it to a stake in City Park. After some trouble involving the park superintendent’s chicken coop, Billy Bear was relocated to the north side of the park, where he marked the start of the zoo that occupies the same space today.
Initially the zoo was intended as just another attraction within City Park. With no fence or entry fee, visitors could simply stroll or drive past the animals on their way through the park. City landscape architect Reinhard Schuetze laid out a Victorian plan of cages along carriageways, and animal care was added to the duties of existing park staff. Nevertheless, the zoo was different from the park, and already by 1900 the Zoological Department had its own accounts and a couple of dedicated employees. The first animal keeper, Alfred Hill, was charged with the difficult task of keeping the zoo clean and orderly.
At various times park leaders articulated a vision of preserving what early Denver historian Jerome Smiley called “the almost extinct wild animals of Colorado” and followed up with a collection that included an eagle, deer, elk, bison, moose, bighorn sheep, wolves, coyotes, mountain lions, foxes, and prairie dogs. But the zoo also took whatever else it could get, including Great Danes, Cotswold sheep, Angora goats, and a wide variety of exotic pheasants from a breeder in Littleton. The first monkeys arrived in 1908 and soon became a star attraction. After many of them died of tuberculosis in the early 1910s, the park board bought different species that were less susceptible to the disease.
By the 1910s, the zoo had grown to the point where city leaders decided to plan for its future. Multiple new designs were proposed in the first half of the decade, but they were lost in the shuffle of municipal reorganizations during those years. The idea that finally stuck was developed by Schuetze and new animal keeper Victor Borcherdt. Borcherdt had been hired in 1912 after serving as taxidermist and then head of the Colorado Museum of Natural History (now the Denver Museum of Nature & Science), which had become the zoo’s neighbor in 1908. Borcherdt and Schuetze’s plan called for a “Habitat Zoo” modeled on Carl Hagenbeck’s famous zoo in Stellingen, Germany, which had opened the previous decade and marked the first shift away from Victorian cages toward more naturalistic zoo design. “Habitat Zoo” would replicate rocky outcrops using concrete molds, with multiple units for bears and other mountain-dwelling creatures—and no bars obstructing the view.
Funding came from the city in 1916, after Robert Speer began his second stint as mayor, and construction started the following year, with workers taking molds of an outcrop near Morrison. Progress was slow because American entry into World War I caused spikes in the cost of labor and materials, but the bear unit (the only one to be built) was ready by winter 1918. The $50,000 spent on Bear Mountain, as the exhibit was known, dwarfed all previous zoo expenditures, but it made the Denver Zoo the first in the United States to deploy naturalistic design. It quickly became the zoo’s main attraction.
Bear Mountain briefly placed the Denver Zoo among the most advanced American zoos, but it soon lost that status. The zoo was not a priority under Mayor Benjamin Stapleton, who served all but one term between 1923 and 1947. The superintendent in these years, Clyde Hill (Alfred Hill’s son), who served from 1924 to 1959, focused primarily on pleasing the public with entertaining stories about the animals. A lot of people came, but the zoo had a low budget and saw few permanent improvements.
Hill did make some changes. An old building on the north side of Duck Lake became a pavilion for tropical birds, and there were new cages for monkeys, pheasants, and foxes, as well as mounds of rocks and dirt for bighorn sheep. The most significant addition was Monkey Island, built in the 1930s with New Deal funding. In general, though, the zoo received little federal aid during the Great Depression, and budget constraints caused the zoo population to naturally decline as animals died and were not replaced. By the end of World War II, the zoo held half as many animals as in 1929, when Hill had been overseeing a handful of alligators, 140 mammals, and more than 1,600 birds. One key addition during these years was Velox, a polar bear who delighted Denverites for two decades.
After the war, civic leaders started to recognize that the zoo’s steady decline had made it a mild embarrassment. The zoo started to turn around in 1947, when Quigg Newton replaced Stapleton as mayor. As part of a broader transformation of Denver, Newton focused on creating a cultural environment more conducive to private philanthropy. At the zoo, that meant bringing in advisors from the natural history museum, which had its own board of trustees as well as a strong record of private giving. By 1950 the grassroots Denver Zoological Society had formed to support the zoo. Led by Lawrence Cook, the society spearheaded fundraising for the zoo’s first elephant, Cookie, who arrived that July to giant crowds.
In the fall of 1950, the Denver Zoological Society got folded into the city's effort to create the Denver Zoological Foundation. Incorporated on November 1, the foundation consisted of twelve prominent trustees (including Cook, Helen Bonfils, and Charles Boettcher II) and was led by lawyer Frazer Arnold. After years of squabbles about how much power the foundation should possess, it was finally contracted to run the zoo in 1956.
With a governance framework in place, the zoo embarked on a decade of major change under the leadership of Helen Johnson, who became board chair in 1957 and served until 1978. In 1957 a perimeter fence separated the zoo from the rest of City Park, and two years later the zoo became closed to cars. In 1959 the foundation hired zoo design firm McFadzean-Everly to develop a master plan, which guided the zoo’s growth for the next three decades. In the 1960s alone, the zoo built a new Feline House (1964), Giraffe House (1966), and animal hospital (1969), while also increasing the number of species in its collection by 57 percent. A new Primate House and revamped Monkey Island followed in 1970. Johnson and her husband, Arthur, drove the fundraising efforts for these improvements, aided by the start of the zoo’s first admission fee in 1966.
If the 1960s brought new infrastructure, the 1970s saw a shift toward professionalization and education. The zoo’s redevelopment continued under director Clayton Freiheit, a prodigy brought in at age thirty-two; he served from 1970 until his death from lung cancer in 2007. Over the next decade, the zoo hired its first curator, education specialist, and full-time veterinarian; became a fully accredited member of the American Association of Zoological Parks and Aquariums; and got involved in conservation efforts around the globe. In 1975 it opened Bird World, which allowed people to walk through a variety of habitats with no separation between them and the birds, and in 1979 it built new mountain sheep habitats with artificial rock ledges reminiscent of Bear Mountain.
Like Denver’s other major cultural organizations, the zoo took a hit during the 1980s oil bust. The state ended its cultural subsidies in 1982, and the city, itself suffering from the oil bust and the effects of suburbanization, proved unable to make up the difference. With high fixed costs tied to feeding the animals, the zoo had to scramble for funding. It raised admission fees in 1982 and 1985 but did not see funding stabilize until the state legislature created the Scientific and Cultural Facilities District (SCFD) in 1987 and voters approved a new 0.1 percent sales tax a year later. Funding started to flow in 1989 and has been a boon for the zoo, which received more than $1 million in the first year. Today the zoo receives roughly $9 million annually in SCFD funding, more than one-fifth of its budget.
Funding troubles slowed the development of new zoo exhibits. The only major addition of the 1980s was Northern Shores (1987), a thematic grouping that included habitats for polar bears, arctic wolves, seals, and sea lions. The zoo also planned the final piece of its 1959 master plan, an aquarium that eventually became the Tropical Discovery exhibit (1993).
With the old master plan completed, the zoo needed to chart its future. It hired Zooplan Associates to develop a new master plan, which called for more thematic exhibits like Northern Shores. The first project developed under the new master plan was Primate Panorama, an updated exhibit intended to provide visitors with an experience of “landscape immersion.” The $11.5 million exhibit opened in 1996, the zoo’s centennial, with large habitats for orangutans, gorillas, and other primates.
Building off that success, the zoo focused in the early 2000s on continuing to develop thematic habitats that were also at the leading edge of zoo design. The most prominent of these was Predator Ridge, which opened in 2004 near the zoo’s entrance. With multiple zones through which the exhibit’s lions, hyenas, and wild dogs could be moved, it was a pioneering example of a rotational habitat and has proved enduringly popular with visitors. Eight years later, the zoo followed up with Elephant Passage, a series of linked yards covering a total of ten acres. Elephants roam across the bulk of the exhibit, but there are also areas for rhinoceroses and Malayan tapirs. In 2017 the zoo opened a new tiger exhibit, The Edge, which helped push annual visitation to a record 2.2 million.
Today the Denver Zoo faces a variety of challenges, including older exhibits and aging animals as well as a fixed footprint within City Park. CEO Bert Vescolani, who was hired in 2018, has said that the zoo will probably have a smaller, more focused collection of animals in the future. A new master plan designed in 2015 calls for redevelopment around three geographically themed regions—Africa, Asia, and Coastal—as well as a “Denver Zoo Into the Wild” exhibit highlighting the zoo’s conservation work around the world. The plan’s first project, the $20 million Helen and Arthur E. Johnson Animal Hospital, opened in 2020, followed by the neighboring Schlessman Family Foundation Visitor and Education Center in 2021.
In the spring of 2020, the zoo closed its doors for three months at the start of the COVID-19 pandemic. By the summer, it was able to reopen with timed entries, reduced capacity, and a one-way path, but revenues were still far below normal, forcing the zoo to recalibrate some of its plans. The zoo’s SCFD funding remained relatively stable, however, and the organization hopes that its 125th anniversary in 2021 will draw plenty of donations and visitors to make up the difference.