Experts believe a sick whale spotted off Kauai this week may be suffering from scoliosis, or curvature of the spine.
It's a rare disorder but scientists say they have seen it in other marine mammals like dolphins.
The National Oceanic and Atmospheric Administration's marine mammal response coordinator, David Schofield, says officials are confident the whale was either born with the condition or acquired it over the course of its life.
The Honolulu Star-Advertiser newspaper reported Friday that Schofield ruled out a boat collision, saying it's not plausible an animal hit by a boat would have retained the shape of such an injury.
A flight instructor on Kauai spotted the white, emaciated whale with a severely deformed spine on Monday. He said the 50 foot whale "appeared to be bent in half."