Hello all,
Well i'd better throw in my two-penneth's worth!
I agree with most of what's been said:
1) We shouldn't be surprised to see amphibians or reptiles hibernating in
any subterranean place. Frog, toads, newts and all reptiles in mid-latitudes
can be found hibernating in all manner of burrows, cracks, crevaces, voids,
tree-bases, under logs etc, in fact anywhere that retains an ambient
temperature above zero. Male frogs (mainly) tend to hibernate in pond
bottoms though. And communal hibernation is not unusual, particularly as
hibernacula are often used year-on-year.
2) Can this cause a problem with archaeological interpretation? Yes,
potentially it can - but not necessarily. It just demands that the
probabilities of different interpretations are weighed up objectively
...which is what science is about. People have often asked me if small
amphibian and reptile bones are vertically mobile. I'd have to say yes,
potentially - but the AMS radiocarbon dates i have on herp bones from caves
are generally remarkably similar (statistically identical) to those on large
mammal and artefact typology from the same layers. However, bioturbation of
soil can be an obvious problem.
3) Somebody picked up on a crucial point earlier: if you have whole
skeletons, especially in small discrete features such as posthole fills,
then it points towards intrusion, but it could also be from a pitfall
contemporary to the original feature. Amphibians in particular are very
clever at falling down holes and not getting out again (as noted by Phil &
Terry). This is likely to occur most at times of migration, especially
spring and autumn. I worked on material from a Medieval farm in southern
Sweden with Britt-Marie Hagerman, and she had counted the remains of 933
juvenile amphibians from a single pit! (Mostly R. temporaria 831
individuals, 62 B. bufo, 40 R. arvalis). I can only assume that juvenile
amphibians were thicker on the ground there before modern land drainage,
maybe dispersing in late summer/autumn to hibernate, possibly accumulating
over several years. One thing is for sure: amphibians and reptiles were once
much more common than today. I reckon about an order of magnitude more
common, as late as Medieval times. The landscape was not so intensively
managed in Europe as it is today and there were more ponds (and insects).
There are lots of Old English (and old Swedish) place names referring to
frogs, snakes, 'worms' etc, and the folklore is full of them - animals that
aren't common enough these days to catch people's attention.
3) epiphyses - they detach very quickly except in older animals where they
ossify very strongly.
That's probably about it for now. Very interesting debate though.
cheers,
Chris
Dr Chris Gleed-Owen
Research & Monitoring Officer
The Herpetological Conservation Trust
655A Christchurch Road
Boscombe
Bournemouth
Dorset BH1 4AP
tel: 01202 391319 fax: 01202 392785 mob: 07810 770567
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