> Remember cage covers and providing ferrets with dark areas to sleep.
> There are so very many careful peer-reviewed studies, not only originally
> showing why too much light exposure can cause adrenal tumors but also
> independently confirming that too much light results in too little
> melatonin production by the ferrets' pineal gland, which is turn results
> in more production of LH and FSH by the ferret's pituitary which starts
> the process. Too much light exposure may also play a bad role in some
> other endocrinological tumors, both malignant and benign ones just as it
> does for humans. (You can find a lot in archives and in PubMed.) The
> safest light coloration for least disruption of melatonin production by
> the body is amber. The worst is blue, followed by green. (BTW, this is
> also why people with some types of blindness have lower levels of
and Shirley replied:
> Sukie, I wonder if you could word that a little more clearly. As you
> can no doubt imagine, some of my posts generate a lot of replies and
> questions off-list. One thing that keeps cropping is that some folk
> understand that you recommend to keep ferrets in darkness 24/7. I'm sure
> that this is not your intent, but it is the message that some get.
>
> Ferrets only need an uninterrupted period of NIGHTTIME darkness to produce
OR they can get the darkness at other times. What is natural for us is
not natural for them. The ancestral pattern of sleeping in darkness
(very dark, purloined burrows) for ferrets is a broken one (an
interrupted one), with two main periods of activity. Polecats have
mostly crepuscular activity: dawn and dusk activity, with sleeping in
the dark, dark, dark burrows in much of both both day and night. It IS
known from human melatonin studies that certain amount of uninterrupted
darkness is needed for optimal production. If memory serves, optimal
production begins in humans after about 4 or 5 hours of darkness
(preferably complete for the best production levels), so if similar
time frames exist in ferrets sleep in darkness can happen in multiple
shorter chunks with enough time for optimal production. I'll have to
look it up for those mammals studied when I get a chance.
For ferrets the amount of truly dark time needed is about 14 hours in
each 24. Remember that older animals, like older humans very possibly
are not as good at producing their own melatonin, so more may be
needed.
One thing to recall with "natural" lighting is that some areas just
plain no longer even have dark nights. Much of Australia does, in
fact, there many city areas are darker at night than much of U.S.
suburbia. In large parts of the industrialized world there is simply
too much outside light. This has led to the new area of biological
inquiry, scotobiology, which studies the functions of darkness. It is
not just that many animals have important activities which do not
happen during the day, but both plants and animals have
endocrinological functions which are triggered by darkness, as with
melatonin production. A person only needs to take a look at
http://www.inquinamentoluminoso.it/worldatlas/pages/fig1.htm
to see where night light disruption is greatest and the degree. (It
uses false coloration to illustrate and define degrees.)
Meanwhile
http://www.muskokaheritage.org/ecology-night/index.asp
has info in one of its sections on how very far city lights can
disrupt undeveloped areas, including regional national parks.
http://www.mbconservation.org/index_files/page0004.htm
http://www.geocities.com/isebindia/05_08/05-01-3.html
> In my experience, with ferrets that have access to natural lighting this
> is not as necessary.
But you live in the only industrialized continent which does NOT have a
huge amount of light pollution. Seasonal night lengths vary also
according to how close or far any person lives to the Equator. Those
MUST be taken into account. Natural is not enough, but if one is going
to go truly natural in a ferret ancestral sense then there need to be
really dark areas available DAY AND NIGHT just as they used with their
purloined burrows.
> My own ferrets and many of my friends' ferrets have the chance to
> dance, sleep and play in the sunshine. This does not hurt them. In
> fact, because of this, they seem to tolerate incomplete darkness at
> night very well. That is, they do not get adrenal disease.
Remember, too, that adrenal disease development except in the very
elderly is also stopped often by a ferret being whole. Aren't most
of yours whole? In whole ferrets the gonads (missing in neutered
ferrets) have the ability to send "Quiet down!" signals back to the
pituitary and reduce the LH and FSH levels back to reasonable
levels. A neutered ferret doesn't have that ability.
Also, there is an investigation going on of populations of ferrets
without adrenal disease to see if there are genetic differences
involved. It only involves cheek swabs. Did you sent ones from your
crew? If not, I can put you in touch with the university research
team leader, or you can find her contact info in the FML and FHL
archives by just seekign posts containing "Michelle Hawkins".
It's a lot more complicated than what is natural to humans, depending
on: ferrets' own ancestral darkness time patterns being different
from ours and dependent on purloined burrows for much of the time,
the location of the home, the degree of light pollution, whether the
ferrets are whole or neutered, and possibly also genetics.
-- Sukie (not a vet, and not speaking for any of the below in my
private posts)
Recommended health resources to help ferrets and the people who love
them:
Ferret Health List
http://www.smartgroups.com/groups/ferrethealth
FHL Archives
http://ferrethealth.org/archive/
AFIP Ferret Pathology
http://www.afip.org/ferrets/index.html
Miamiferrets
http://www.miamiferret.org/fhc/
International Ferret Congress Critical References
http://www.ferretcongress.org
[Posted in FML 5395]
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