Published: Aug 24, 2011 7:29 PM EDT

KLAMATH, Calif. (AP) - Scientists say they may never know what caused the death of a gray whale that was stranded for weeks in the Klamath River in northern California.
    
Samples taken from the female whale's carcass could take months to process, and even then may not help determine how the marine mammal died.
    
The whale and her calf entered the river June 24. The calf made it back to sea about three weeks later.
    
The mother remained for 54 days, drawing crowds of people to a highway bridge spanning the river to get a glimpse. It finally died after beaching itself on a sandbar in the river.
    
The Yurok Tribe performed a ceremony to send the whale on its journey to the afterlife. Scientists then took samples of the carcass before the tribe buried it.
    
Scientists told the Times-Standard of Eureka they saw no sign of broken bones or bruising, which could occur from a boat strike.
    
Also, research of the whale can give scientists a wealth of new information about ocean conditions.

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