Necropsies performed on 11 dead short-finned pilot whales found in the Florida Keys on Sunday revealed the mammals suffered from malnutrition.
Officials believe the 11 were part of the whale pod that stranded itself in Florida's Everglades National Park last week.
According to the National Oceanic and Atmospheric Administration, the whales' stomachs were found empty, which was caused by either disease or because the pod had swum away from its natural habitat in deeper waters.
NOAA fisheries official Blair Mase announced the findings on Monday.
These 11 whales were spotted floating next to one another by a fisherman around 1 p.m. Sunday at Snipe Point, just north of Sugarloaf Key.
Last week, another fisherman discovered 51 short-finned pilot whales swimming in the shallow waters near Highland Beach, which is about three-quarters of a mile off the shoreline in Monroe County.
Two days later, marine officials were able to push back six of the ten whales that had beached themselves, but four of the whales soon died.
Another six whales were found dead Wednesday, while four more had to be euthanized.
On Friday, the Coast Guard reported that around 20 of the whales had vanished, indicating that they may have swum into deeper waters.
A Coast Guard cutter spotted nine whales swimming in deeper waters -- while two remained in the shallows. But the other whales were nowhere to be found, meaning they could have found their way back into deeper waters.
Short-finned pilot whales are common in the Gulf of Mexico and are often found living in very deep waters. Experts say that it's common for them to strand themselves in large numbers, though experts are divided on why that is.
Officials are still trying to figure out what caused the whales to beach themselves in the shallow waters of Highland Beach.
The whales that were found in the Keys could mean that there are more out and about, although the hope remains that they did indeed swim back into deeper waters.
NOAA is asking fishermen and boaters who spot whales, alive or dead, to report it to 1-877-WHALE-HELP.