A team of English researchers uncovered a curious revelation concerning Egypt's store of mummified animals.

According to BBC News, a team of scientists from the Manchester Museum and the University of Manchester scanned more than 800 mummies only to find about a third did not even have their animals inside the cloth.

The BBC plans to run a documentary on the discovery as part of their "Horizons" program. "70 Million Animal Mummies: Egypt's Dark Secret" will air at 9 p.m. in England (4 p.m. ET) on BBC 2.

"We always knew that not all animal mummies contained what we expected them to contain, but we found around a third don't contain any animal material at all - so no skeletal remains," team leader Lidija McKnight, an Egyptologist at the University of Manchester, said in a press release.

The largest scanning undertaking like it, the researchers suggested so many mummies were created empty because of a large demand for religious practices. Unlike human mummification, which was for preservations, animal mummification was often done to create such offerings.

"Initially, when these mummies were first discovered and the archaeologists unwrapped some of them just to see what was in there, they were quite surprised to see that they weren't complete animals," McKnight told the Washington Post. "Some of their reports and their recordings from those times suggest that they thought they were fakes and that perhaps there was some kind of deception going on the part of the embalmers, who were making these mummies from incomplete remains

She told BBC News the false mummies were packed with "organic material such as mud, sticks and reeds."

The team also found out about another third of the mummies they scanned were only partial skeletons.

"We think there is probably more to it than that," McKnight told BBC News. "We think they were mummifying pieces of animals that were lying around, or materials associated with the animals during their lifetime - so nest material or eggshells.

"They were special because they had been in close proximity with the animals - even though they weren't the animals themselves.

"So we don't think it's forgery or fakery. It's just that they were using everything they could find. And often the most beautifully wrapped mummies don't contain the animal remains themselves."