In 1910, the park officially opened and throughout the year, the zoo received a few more bears, angora goats, fox squirrels, opossums, peacocks, pheasants, and zebus.

[1] By 1934, the zoo covered more than 40 acres, had a reptile house and a pair of baby elephants, but they were sold after Hershey overheard a guest talk about how they prefer the monkeys.

The zoo acquired a variety of new animals including African sheep, antelope, aoudad, bison, black bear, chipmunk, crow, deer, duck, emu, fox, goat, goose, groundhog, hare, hawk, llama, monkey, opossum, owl, parakeet, partridge, pheasant, rabbit, raccoon, skunk, squirrel, and wolf.

Some of the animals include the cottonmouth, roseate spoonbill, fiddler crab, eastern diamondback rattlesnake, bluespotted sunfish, gopher tortoise, pygmy rattlesnake, corn snake, barred owl, Florida gar, alligator snapping turtle and American alligator.

Some animals on exhibit include the thick-billed parrot, blue spiny lizard, Mexican beaded lizard, chuckwalla, Gila monster, roadrunner, Gambel's quail, burrowing owl, desert tortoise, nine-banded armadillo, Arizona mountain kingsnake, Texas banded gecko, common vampire bat, sidewinder, gopher snake, rosy boa, black-footed ferret, ocelot, ringtail, coati, and desert box turtle.

Some animals, which can be seen include the red-tailed hawk, barn owl, bobcat, river otter, white-tailed deer, wild turkey, and black bear.

Some of the wildlife species include the black-tailed prairie dog, common raven, American elk, mountain lion, long-eared owl, sandhill crane, turkey vulture, and pronghorn.

Some animals on exhibit there are the snowy owl, peregrine falcon, gray wolf, bald eagle, porcupine, American marten and Canada lynx.

The zoo currently houses and is working to breed the thick-billed parrots, Canada lynx, black-footed ferret, and ocelots.

In the past, ZooAmerica played a big role in bringing back the golden eagle and peregrine falcon, which were both facing severe threats in the wild.

[12] Beginning in 2011,[13] ZooAmerica became involved in a cooperative project with Fort Indiantown Gap to raise Regal Fritillary butterflies for release.

In 2014, The National Military Fish & Wildlife Association honored two naturalists at ZooAmerica, Tim Becker and Ann Holzman, for their work in the reintroduction of the regal fritillary butterfly to Pennsylvania.