A research project at the Manchester Museum and the University of Manchester has shown that almost one-third of the animal mummies entombed in Egypt do not actually contain body parts or skeletal remains.
In the largest scanning project to date, over 800 animal mummies, including birds, cats and large reptiles such as crocodiles have been examined by CT scan and X-rays. The project was undertaken in conjunction with the BBC television program Horizon.
Experts at the University of Manchester have theorized that since the ancient Egyptians revered animals as gods, having mummified animals with them in the afterlife was a way to honor the gods and possibly gain favor. There would have been a tremendous demand for the mummified creatures, so it's possible embalmers were cutting corners in order to keep the supply up. While some Egyptologists are calling the matter a scandal, it's likely that those citizens asking for animals for their final resting places knew they were simply symbols.
(Source: BBC, YouTube)