The recipes used by ancient Egyptians for mummifying animals were just as complicated as those they applied to dead people, new research shows.
By Paul Rincon
BBC News Online science staff
It suggests Egyptians took just as much care when preparing pets for the next world as they did with their owners.
Pets' organs were carefully removed and they underwent elaborate bandaging before treatment with a variety of chemicals including beeswax and bitumen
The study by University of Bristol researchers appears in Nature.
The Egyptians are known to have mummified a variety of animals, from cows and crocodiles to scorpions, snakes and even the occasional lion.
"If it moved, they mummified it," co-author Richard Evershed of the University of Bristol told BBC News Online.
The sheer numbers in which mummified animals have been found has led some researchers to surmise that they were prepared with little care or expense compared with their human counterparts.
Consequently, the accepted view has been that the ancient Egyptian embalmers did a rush-job on animals, wrapping them in coarse linen and dunking them in a preservative resin.
But organic chemists Professor Evershed, Katherine Clark and Stephen Buckley have now demonstrated this could not have been the case.
The Bristol researchers analysed the mummified remains and wrappings of a cat, two hawks and an ibis bird to reveal the chemical composition of the substances used to mummify them.
Their results showed very complex mixtures of chemicals were used as preservative "balms".
"We found very similar combinations of material to those used to embalm human mummies we've looked at," Professor Evershed commented.
These include a variety of fats and oils, beeswax, Pistacia resin, sugar gum, bitumen, conifer resin and possibly cedar resin.
Beeswax, for example, was shown conclusively to be present by the detection of characteristic constituents such as n-alkanes, wax esters and hydroxy wax esters.
One balm recorded by the classical writer Diodorus Siculus as having been used in mummification - cedar oil - could not be definitively identified. But there were tantalising clues that it might have been used on the specimens.
"Because animals were important to them and they treated them with respect, you would expect to see that reflected in the embalming treatment. This might take the form of nice tidy - and even complicated - bandaging or a sophisticated embalming recipe," explained the Bristol professor of biogeochemistry.
"I suspect the embalming treatment was driven partially by what worked. Particular substances inhibit bacterial activity, so for that reason - as well as the respect for pets - they would have used the same on animals as they did on humans."
Four groups of animal mummy have been identified by researchers: those placed in tombs to be used as food in the afterlife by a dead person, those that were pets of a dead person, animals mummified as symbols of a cult and those given as votive offerings to the gods.
EGYPTIAN ANIMAL MUMMIES
Bird and reptile eggs
The first three are found throughout Egyptian history. But the last is generally restricted to the Greco-Roman period (332BC - AD395).
Researchers propose that, in some cases, animals were mummified before, not after, they died.
The mummies studied by the researchers come from the latest mummy-making period, between 818BC and 343BC.
"The next step for us may be to look at more animals and ask questions related to whether there were specific treatments for specific animals or whether there was any change in the practice through time or location," Professor Evershed explained.
"Perhaps different embalmers had their own secret recipes. We just don't know."
The researchers used combinations of techniques such as gas chromatography, mass spectrometry, thermal desorption, and pyrolysis to characterise the compounds in the wrappings and animal tissue.