ORLANDO, Fla. -

One of the five pilot whales that were a pod of 22 stranded on a Florida beach has died, and the other four are "touch and go," according to SeaWorld Orlando officials.

Two male and three female juvenile whales were being treated Monday at Florida Atlantic University's Harbor Branch Institute for rehabilitation.

Experts at FAU say the whales were showing signs of stress and infection from the stranding Saturday, but the marine mammals were swimming on their own.

SeaWorld veterinarians told Local 6 they're cautiously optimistic about the four surviving whales.

The rest of their pod died of natural causes or had to be euthanized. It was unclear why the whales stranded at Avalon State Park in St. Lucie County.

The experts hope to eventually continue the whales' rehabilitation at SeaWorld Orlando.