The Sunnydale Zoo was the local zoo in Sunnydale.
One of its zoo keepers, Dr. Weirick, was a Primal, a member of an ancient African sect that worshiped deadly animals. He transported a number of demonic hyenas in hopes of drawing their spirits into him. He kept them in an exhibit named the "Hyena House" where he painted on the ritual symbol where the hyenas were kept. He kept it quarantined in order to stop others from intruding and summoning the spirits themselves.
In 1997, the tenth graders of Sunnydale High visited the Zoo on an excursion. During that event, Xander Harris and four other students became possessed by the hyenas after another called Lance was bullied on the seal, triggering the "predatory act". Much to his distress, Weirick teamed up with Rupert Giles and Buffy Summers, who weren't aware of his true intentions and instead wanted to return the spirits back into the hyenas.
Buffy lured the "Pack" back to the exhibit while Weirick knocked Giles out and threatened Willow, drawing the spirits to himself. He then attacked Buffy, but was thrown into the pit with the hyenas and devoured.
In 2000, the hell goddess Glorificus preformed the Sobekian transmogrification spell at the Reptile exhibit. Turning a cobra into a demon, she hoped it would discover the location of the Key. Buffy attempted to stop her but was easily dispatched, although she was able to defeat the demon before it could tell Glory who the key was.
It was presumably destroyed along with the rest of Sunnydale by following the Battle at the Hellmouth.