Was it the oil?
That's the question of the day as the number of stillborn or dead young dolphin calves washing up on Gulf of Mexico shores continues to rise.
The research team called in to investigate the incident has a disconcerting answer: We might never know.
On Friday, five more dead baby bottlenose dolphins were found in Mississippi and Alabama, pushing to 67 the number of dolphin carcasses tallied since Jan. 1 on beaches from Louisiana to the Florida Panhandle. Of those, 35 are so young that they might be spontaneously aborted fetuses, making this "unusual mortality event" even more unusual, though not unprecedented.
But determining the cause of this, or any other, wave of dolphin deaths is a huge challenge.
There are no witnesses to interview.
The whereabouts of the dolphins before they died is unknown.
Any unusual behavior preceding death went unobserved.
And, worst of all for the federally coordinated team investigating the incident, all the carcasses are badly decomposed.
"A lot of the organs are mush, basically," said Blair Muse, who collects reports of beached dolphins in the southeastern United States for the National Marine Fisheries Service. "They are coming ashore decomposed. It may prohibit us from determining the cause unless we get some fresh bodies."
That's bad news for the teams scouring beaches to collect whatever blood and tissue samples they can, the laboratories rushing to analyze those samples and the scientist who will eventually try to piece together the spotty evidence.
Those limitations also explain why the record of determining the cause of mass marine mammal deaths has not been good.
Dolphin cold case: Investigators say cause of calve die-off may never be known
on 6:00:00 AM