Thresher shark photographed mid-birth

CHESTER, England, Jan. 13 (UPI) -- Researchers at a British university said they captured the first photo of a thresher shark giving live birth while observing sea creatures in the Philippines.

The University of Chester researchers, who published the photo in the journal Coral Reefs, said they noticed an "agitated" female thresher shark at a "cleaning station" where sharks go to cleansed of parasites by fish called cleaner wrasse.

The researchers took the photo of the shark and only later noticed "the head of a pup emerging from the shark's cloaca."

"While interactions among thresher sharks and cleaner fish are well documented at this site this is the first time cleaners have been seen interacting with a marine organism while it gives birth," the researchers wrote.

Dr. Simon Oliver, the lead researcher, told BBC News the photo from 2013 represents the "the first record of any oceanic species giving birth."

"It looks like this area is not just a cleaning station, which is already massively essential, it's also serving as a pupping ground," he said. "We've seen lots of [pregnant] females there, so I don't think this is a one-off."