From:
Sukie Crandall
Date: 2001-04-07 13:19:00 UTC
Subject: what we noticed here in relation to darkness and light
Our living situation:
Housing is excessively expensive around here and is in most areas
where Steve could work at his chosen specialty, so we have a small
condo and can not devote a room just to the ferrets the way we would
like to do, due to lack of space. They do get a large amount of
"out" time -- about 12 to 14 hours every 24, typically.
They have lighting in daytime hours and black window curtains, plus
black cage covering for night that exclude most light (Gets very
black in there.); when they also get into the bedding it's likely
that pretty well all light is excluded.
What we have seen: we are still having adrenal neoplasias develop,
but have not seen any adrenal malignancies since the use of the
covers.
Interestingly, years ago we saw very few adrenal growths. Now, early
on (We've had ferrets for around 19 years.) the vets didn't tend to
recognize adrenal growths, anyway. Still, even taking that into
account there HAS been a very real change over the years at least in
our household. Adrenal neoplasias have become more common and just
this last year we are actually seeing them earlier --in middle age
rather than old age. Adrenal malignancies have not been seen here
since the night covers. I don't know if any of that reflects any
actual change or just some random clumping; family groups simply are
not large enough to permit hard conclusions, even despite other
aspects that present interpretation difficulties. Meanwhile, we have
also personally encountered less lympho in recent years, which also
may mean squat. It's pretty well impossible to tell anything
conclusive from a small sample.
There are a number of research articles that exist on levels of
natural melatonin production (from light exclusion) and how having
enough darkness appears to be able to reduce rates of hormonally
related malignancies in humans and in rodents. The line of inquiry
began largely because it was noticed that blind people with certain
forms of blindness had lower levels of some hormonal cancers. There
was a large article a few years back in Science News which did a
wonderful review of most of the related studies at that time; it may
be at their website.
I have heard form others who have also noticed a trend toward adrenal
neoplasias happening earlier, but do not know how much of that is
coincidence.