Veterinarians working for the zoo claim the animals are susceptible to the coronavirus, which is why they need the experimental and dangerous vaccines.

"Animal health and human health are closely connected," claimed Dr. Gary West, a veterinarian and Phoenix Zoo's vice president for animal health and living collections. "We started seeing increasingly concerning reports from other zoos where the large cats, tigers, lions, snow leopards were acquiring the infections from their human caretakers."

Because of this, Phoenix Zoo authorities decided to choose 75 animals who will get the vaccine. These included Sumatran tigers, bobcats, jaguars, African lions, orangutans, emperor tamarins, Egyptian fruit bats, three-banded armadillos and Linne's two-toed sloths. (Related: MIND-BLOWING: Oakland and Denver zoos giving COVID-19 spike protein vaccines to animals – including bears, gorillas, tigers and mountain lions.)

The tigers, bobcats, jaguars and lions were vaccinated from a distance using darts that contained the shots. They are expected to receive a second dose – which will serve as booster doses – soon. "They take it way better than people do," said West. "They don't like it, but they bounce right back and go back to their lives."

"So far, we really haven't seen anything significant. Maybe some mild lethargy in a couple of our primates but really, nothing major," he added, talking about the vaccine's immediate side effects on the animals. "In addition to guest-facing measures deployed, we have been taking precautions during the pandemic behind-the-scenes to keep our animals safe."

Some of these precautionary measures include zoo staffers keeping their distance from the animals and wearing protective equipment. West said zookeepers have to wear masks and gloves whenever they come close to animals. Places in the zoo that allow visitors to get a little closer to the animals are currently still closed.