If you like shrews, especially if you like them parboiled, you'll want to devour a study published not long ago in the Journal of Archaeological Science. Called Human Digestive Effects on a Micromammalian Skeleton, it explains how and why one of its authors - either Brian D Crandall or Peter W Stahl; we are not told which - ate and excreted a 90mm-long (excluding the tail, which added another 24mm) northern short-tailed shrew (species name: Blarina brevicauda

This was, in technical terms, "a preliminary study of human digestive effects on a small insectivore skeleton", with "a brief discussion of the results and their archaeological implications".

Crandall and Stahl are anthropologists at the State University of New York in Binghamton. The shrew was a local specimen, procured via snap trapping at an unspecified location not far from the school.

For the experiment's input, preparation was exacting. After being skinned and eviscerated, the report says, "the carcass was lightly boiled for approximately two minutes and swallowed without mastication in hind and forelimb, head, and body and tail portions".

Here's how Crandall and Stahl handled the output: "Faecal matter was collected for the following three days. Each faeces was stirred in a pan of warm water until completely disintegrated. This solution was then decanted through a quadruple-layered cheesecloth mesh. Sieved contents were rinsed with a dilute detergent solution and examined with a hand lens for bone remains." They then examined the most interesting bits with a scanning electron microscope, at magnifications ranging from 10 to 1,000 times.

A shrew has lots of bony parts. All of them entered Crandall's gullet, or maybe Stahl's. But despite extraordinary efforts to find and account for each bone at journey's end, many went missing. One of the major jawbones disappeared. So did four of the 12 molar teeth, several of the major leg and foot bones, nearly all of the toe bones, and all but one of the 31 vertebrae. And the skull, reputedly a very hard chunk of bone, emerged with what the report calls "significant damage".

The vanishing startled the scientists. Remember, they emphasise in their paper, that this meal was simply gulped down: "The shrew was ingested without chewing; any damage occurred as the remains were processed internally. Mastication undoubtedly damages bone, but the effects of this process are perhaps repeated in the acidic, churning environment of the stomach."

Chewing, they almost scream at their colleagues, is only part of the story. In each little heap of remains from ancient meals, there be mystery aplenty.

Prior to this experiment, archaeologists had to, and did, make all kinds of assumptions about the animal bones they dug up - especially as to what those partial skeletons might indicate about the people who presumably consumed them. Crandall and Stahl, through their disciplined lack of mastication, have given their colleagues something hard to chew over.

(Thanks to Michael L Begeman for bringing this to my attention.)

· Marc Abrahams is editor of the bimonthly Annals of Improbable Research and organiser of the Ig Nobel prize