>more recent rat mummies found in buildings are often dessicated, and
>therefore well preserved, just because the animals got poisoned. A set of
>toxic agents, such as Warfarin or difenacum, are anti-coagulantia and rely
>on causing internal bleeding, making the animals dry out and die slowly on
>their nest, instead of collapsing immediately on the feeding spot (which
>would stress other members of the population). Of course, this is a
>20th-century phenomenon. However, already during the (European) late middle
>ages (13th - 14th century AD), substances such as arsenicum were used to
>destroy rodents and, if I'm not completely wrong, this is also a dessicating
>agent. At least, I know it was used formerly by taxidermists for that
>purpose (e.g., to inject in bird wings). Other substances can well have had
>the same effect.
Arsenic is not a desiccating agent _per se_. However it is just about the
only thing that will stop any and all scavengers, including microorganisms,
literally dead. It is still used by museums to preserve specimens like bird
skins, despite its' obvious risks and drawbacks. Nothing else seems to work
nearly as well.
So, arsenic should be considered as a possibility if You find any
"suspiciously" well preserved specimens.
Tommy Tyrberg
|