What started out as a normal day for a group of fishermen turned into one they’ll never forget.

Their heroic journey began when they discovered a huge sperm whale that was stuck 740 meters from the coastline of the beach. They quickly phoned their local fishery agency for aid as they understood they had to take action to help rescue the 65-foot-long whale. The Chinese state of Zhejiang hosted the rescue, which started at 8 a.m. and took 20 hours to finish.

The whale’s ultimate fate, however, will probably never be known. Strandings are difficult on sperm whales (Physeter macrocephalus), and animals don’t always survive even if they are rescued, said Bruce Mate, professor emeritus in fisheries, wildlife and conservation and the past director of the Marine Mammal Institute at Oregon State University’s Hatfield Marine Science Center.

Even when a healthy animal gets stranded, the stranding itself may damage the organs beyond repair. According to Mate, the sperm whale’s vascular system isn’t meant to function on land. The longer an animal is stranded out of the water, the more harm it may endure to its tissues as they begin to deteriorate.

“Good on them for making a noble effort in trying to get this animal back to sea, but the odds are quite difficult,” Mate told Live Science.