animals. Besides an extensive collection of birds, reptiles, and mammals, it also maintains its grounds as an arboretum, with a rare plant collection. The zoo is also an accredited botanical garden; the botanical collection includes more than 700,000 exotic plants. As part of its gardening effort, some rare animal foods are grown at the zoo. For example, 40 varieties of bamboo were raised for the pandas when they were at the zoo on long-term loan from China. It also maintains 18 varieties of eucalyptus trees to feed its koalas. Keepers and most other employees at the San Diego Zoo are members of Teamsters Union Local 481. Exhibits The zoo is expected to open a new exhibit, the Sanford's Children Zoo, sometime in 2021. Monkey Trail and Forest Tales Monkey Trails showcases primates and other animals native to the tropical and semi-tropical rainforests of Asia and Africa. Opening in 2005, it replaced a decades-old area of exhibits known as Ape and Bird Mesa. These were some of the oldest animal "houses" still in use (at the time) at the San Diego Zoo, being built in the 1930s, with little to no change until demolition for Monkey Trails. In addition to a few small bird aviaries and a troop of siamang apes living on a treehouse in the center of a pond, the site was centered around two square buildings; these plain structures contained many small exhibits lined up, one after another, on all four sides. One of the buildings was focused on monkeys, while the other was mainly songbirds, parrots, and tropical avian species. There had been a few efforts at landscaping these cages; however, the monkeys notably lived in bleak, "prison-cell" like cages. A number of Zoo members and guests left comments over the years regarding the exhibits and their lack of plant life, the (apparent) lack of enrichment for the monkeys and, mostly, the appearance of cement "cell blocks" as exhibits. The construction and debut of Monkey Trails and Forest Tails was undoubtedly a massive improvement, enriching for visitors but especially for the animals. Monkey Trails is home primarily to monkeys such as the Angolan colobus, lion-tailed macaque, tufted capuchin, red-tailed monkey, DeBrazza's monkey, spot-nosed guenon, Douc langur and a group of colorful mandrill. There is also a pair of pygmy hippopotamus named Elgon and Mabel, who share their underwater-viewing pond with a large school of African cichlids and