I would have answered this yesterday, but Sunday was grandpa day. For
Christmas, Gloria gave me a Heather, and for my birthday, Elizabeth
is going to give me an Elaina. All is right in the world! ;-)

Shirley said in a disarming Australian way,
>Yes, I'm still confused about using the term "crepuscular" when
>describing polecats and, therefore, ferrets.

As far as I am concerned, ferrets define confusing. I am still trying
to figure out how they know exactly where to poop so it is impossible
for me to step over the barrier without sliding in it. I call it "me
poopdeck." They call it, "Bob falls on his butt-deck."

Then Shirley wondered brightly,
>Bob, from your post, should I better understand that "crepuscular"
>means "able to be active any time during a 24 hour period as the
>opportunities for survival present themselves?

Well, no, not in a 24 hour period, but yes, extended around (before and
after) dusk and dawn times. There are three basic activity cycles:
daytime (diurnal), nighttime (nocturnal) and dawn/dusk (crepuscular).
Daytime animals have vision and other senses that are specialized for
bright light. Baboons are daytime animals, and generally retreat to
trees or other shelter at night. Other diurnal animals include prairie
dogs and many squirrels, many lemurs, a majority of primates, and a lot
of ungulates, such as pronghorn, mountain sheep, and antelope. They are
rarely active at night except if disturbed. Many of these animals have
some type of color vision (but limited in some).

Nocturnal animals have eyes (and other senses) adapted for darkness.
Flying squirrels are nighttime animals and generally retreat to nests
during the day. Other nocturnal animals include Virgina opossums,
bushbabies, sugar gliders, ocelots, and lots of rodents. They are
rarely active during the day unless disturbed. Most of these animals
only see in shades of gray, although some might have very limited color
vision.

Both nocturnal and diurnal activity patterns represent specialization
in the light cycle. If we were talking diet, they would represent
strict carnivores and herbivores. They are light cycle specialists.
Crepuscular animals, on the other hand, have to have visual and other
senses that can be used at night as well as day. That makes them light
cycle generalists, sort of like how omnivores are dietary generalists.
They do not specialize in a nocturnal nor a diurnal lifeway, but can
do both.

Most crepuscular animals have two activity periods, at dawn and at
dusk, although not all follow this rule. As a general rule of thumb, in
the morning they come out when the dark is brightening and retreat to a
den or hiding place when it becomes light. The opposite pattern is seen
in the evening, when they come out during the late daylight, through
dusk and into the early night. Because these animals are generalists,
they can adapt their activity pattern to better fit the local
environment. For example, golden jackals are crepuscular, but will
become nocturnal around human habitations. Polecats have been reported
to follow the same pattern. Many crepuscular predators will shift to
a diurnal lifeway to exploit seasonal prey. These animals are more
plastic in their responses than the more specialized nocturnal and
diurnal ones. For example, bats and flying squirrels have not been
seen to exploit a daytime niche if their nighttime one is somehow
unsatisfactory, but crepuscular coyotes can show diurnal, crepuscular
and nocturnal activity patterns -- or any combination in between.

I was probably a bit harsh when discussing how biologists view these
activity periods; I was referring to the older literature. Many
modern biologists now use terms such as "strictly diurnal,"
"diurnal-crepuscular," "strictly crepuscular," "crepuscular-nocturnal,"
"strictly nocturnal," or "nocturnal-crepuscular" to better describe the
particular light cycle niche the animal is filling. You should note
that these terms recognize the independence of the three light cycle
activity periods, which means many modern biologists do not consider
crepuscular as a subset of nocturnal.

Then Shirley book-wisely added,
>The dictionary definition leads one to understand that crepuscular
>animals are either mainly or exclusively active during dawn and dusk.

I have a compulsion to own dictionaries. I must own a couple hundred of
them, including more than 50 on biology and zoology alone. It is
surprising how many dictionaries do not agree with each other, and as a
science matures, definitions can change. Also, many dictionaries are
like reading the abstract to an article; they provide a basic idea, but
miss all the subtleties.

Yes, the definition is more-or-less true, but it doesn't allow for
the plastic nature of the lifeway: a crepuscular animal can modify
its activity cycle to better exploit a given environment. Now, some
crepuscular animals are less plastic in their responses than others,
but all are generally more plastic than nocturnal and diurnal animals
and will shift activities towards night or day as the needs demand.

Then Shirley pleaded,
>Please let me be right this once.

I will not comment on your political belief system. While I tend to be
on the left of the political spectrum, you can be right all you want.

Then Shirley, with a Luke Skywalker-like epiphany, said,
>I have often wondered if, therefore, many of us have similarly
>misunderstood the term and this has led to thinking that ferrets only
>need (for instance) to be let out of a cage once or twice per day
>(dawn and dusk). I know from my own experience, and I bet others do
>too, that ferrets need to be much more active than this!

Well, Shirley, I've been arguing that point for a decade now. I have
been accused of trying to guilt people into changing, forcing my
perspective down people's throats, and even advancing some sort of
egotistical agenda. Not one person -- or their remarks -- has been able
to dissuade me from my singular mission: to make ferret lives better
(it is not just, as one person said, "to piss as many people off in
as short a time as possible." If that was the case, I could do a much
better job). I only hope I can anger people for another decade.

I have ferrets that have never been in a cage, excluding the carrier
to go to the vet, or the occasional hospital confinement. I see a
tremendous difference in the attitude and behavior of ferrets that are
caged, compared to my own. My ferrets have two major activity periods,
BUT, they might have a number of minor periods of activity during a
24-hour cycle. My ferret room faces south and all windows are open to
light 24-7. The overhead lights are full spectrum and come on (and go
off) by a timer I wired into the main light switch, so they come on
roughly 15 minutes after sunrise and go off 15 minutes before sunset.
I also have a deep amber darkroom light I use at night that puts out
about as much light as a full moon. I use amber because ferrets are
reported to see in blues and reds, so, like b&w photo paper, they
should be "blind" to amber light (or are at least somewhat limited)
in the same way we are blind to infrared.

Under this lighting, they have a major activity period in the morning
that starts about an hour before dawn and lasts about 3 to 4 hours. I
feed them breakfast during that activity period, but not at a specific
time. Then, like a switch is thrown, they crash in sleeping (nest)
boxes that provide 90% darkness or better. About 4pm, most or all of
them will wander around the room because they know I check water and
treats about that time. This activity period lasts about an hour. Some
ferrets might nap in the open at this time. Around an hour before
sunset, they will start getting up for the evening romp, and this
activity period lasts about 4 to 5 hours. They get their evening meal
at this time, but again, never on a regular time schedule. Then about
3 am, most of them will get up for about an half-hour to an hour. Most
of my ferrets are awake 8 to 10 hours a day, with roughly a quarter
of that time during daylight hours, half during dawn/dusk, and the
remaining quarter during night. Even my elderly ferrets are up at least
6 hours a day.

(part 2 to follow)
[Here it is -- parts combined.  BIG]

Caged animals sleep a LOT more, which is why I think many ferret books
overestimate their sleeping requirements. I think the long sleep
periods are a ferret adaptation to boredom and cage captivity. All I
can say is, if a person HAS to have their ferrets in a cage, they
should also have an enrichment program to offset the problems of cage
boredom and stress AND have the ferrets out of the cage as much as
possible. Even if the ferrets get out of the cage a lot, they still
should be provided a serious enrichment program.

I am deadly serious. Cage (confinement) stress has been proved to
shorten the lives of all mammals studied, including humans. I have a
hypothesis that ferrets with good dental hygiene and a superior diet
should live to be about 8 to 10 years of age, PROVIDING they are not
negatively impacted by cage stress. I think the average lifespan of
ferrets, reported to be between 5 to 7 years in North America, reflects
dental disease, poor diet, and cage stress. Anyone notice those are the
three main areas, outside domestication, that I concentrate my research
on? It is NOT a coincidence. The only effective ways to reduce cage
stress is by giving your ferrets a lot of free time, as well as an
effective enrichment program. While all three areas are extremely
important, I rank cage stress being the most important, closely
followed by dental disease, and then diet.

Then Shirley inquisitively asked, "I have further concerns that a
current trend to provide absolute darkness for a period of time per
24 hours to prevent adrenal disease has been seen by some as a need
to occlude light for as long as possible. I think this could be very
dangerous."

Now THAT is an interesting question. If there is a single person on the
planet that has a good understanding of adrenal disease, it would be
Dr. Nico Schoemaker of the Netherlands. I've met Dr. Schoemaker twice
now, and the last time we managed to get a few stern looks as we played
with a black-footed ferret puppet as Dr. Susan Brown was giving her
presentation at the Dutch ferret symposium. Hey, she threw it at us! It
took a while for Dr. Brown to figure out why the audience was giggling
when she turned her back. Later, we played with the puppet during a
question-answer period and managed to startle her a bit when Dr.
Schoemaker snuck the puppet behind her to bite her neck. I spent much
of the next day with Dr. Schoemaker, and if we were not goofing around
and driving Drs. Brown, Nye, and Moorman-Roost crazy, I would discuss
adrenal disease with him. Mostly we just goofed around until it was
time to eat giant pancakes for dinner. Still, he gave me great insight
into the disease, as well as future prospects for prevention.

Now, I can't speak for Dr. Schoemaker, some of the stuff I was told
was confidential, and my understanding of the disease might be off,
but while there are certainly other factors involved, the main reason
ferrets get adrenal disease is because of neutering. Neutering is a
high risk factor (not all neutered ferrets get adrenal disease and some
whole ones will). If you consider a line where 0% occurrence is at one
end and 100% occurrence is at the other, whole animals are somewhere
towards the 0% end of the scale, while neutered animals are somewhere
more towards the 100% end of the line. Of all the factors which could,
should, or would be involved in adrenal disease, apparently the most
paramount is neutering.

That begs the question, how important is the light-dark period? Well,
it certainly can bring a ferret into heat or rut; that has been known
since shortly after the electric light bulb was invented. But when it
is compared to neutering and a risk assessment is done, how important
is it? Honestly, I can't answer that question. I do have some data that
I've promised not to share at the moment, that suggests factors other
than neutering are relatively insignificant. Not that they don't have a
bearing and might contribute to the problem, but as far as I have been
informed, neutering remains the primary causative agent.

Which brings us back to light. Do ferrets need light? My answer is
"absolutely!"

There is no doubt that polecats sun themselves; it is reported in the
literature. There is also no doubt that ferrets will do the same thing.
I used to have the opinion that sunning was primarily done to warm up,
especially after a deep sleep. But then I noticed my ferrets were doing
it on hot days. I asked myself, "Why would they be sunning on a day
when it was clearly not to warm up?" Not long after that, I started to
do density tests on ferret skeletal elements to check for osteoporosis,
and I was struck with the lowered density values when compared to
polecats and feral ferrets. Then I noticed my first ferrets, which
lived indoors, had an average lower bone density than my later ferrets,
who went outside. Why?

I think the simplest answer is the ferrets that go outside make more
vitamin D than those that have limited access to sunlight. Vitamin D is
required to better absorb calcium in the diet, and has a direct bearing
on bone deposition and density. I suspect ferrets need sunlight to help
synthesize vitamin D. In captive animals kept indoors, vitamin D
deficiency could be a unresearched and perhaps serious problem. Several
recent papers has suggested vitamin D insufficiency is a serious
problem in America among those who work and stay indoors, and when I
was reading it, I was struck with the similarities between humans and
ferrets kept in shelter conditions. I am currently looking into this
problem and have set up some experiments to create some data, but the
big problem is cost. Another problem is that the vitamin D requirement
in humans is mostly unknown, much less requirement for ferrets. It is
hard to say ferrets are not getting enough when we don't know how much
is needed.

I am about 1/3 way done with a skeletal analysis of ferret -polecat -
black-footed ferret skeletal elements. I have found there is a marked
difference in skeletal element density between neutered pet ferrets and
their wild brethren. Now, in all honesty, there are several factors
that could be driving the differences, including diet, exercise, and
disease. Still, understanding the relationship between calcium and
vitamin D, I have little doubt that sunlight is also a factor.

The bottom line is that I think -- without empirical evidence that
suggests otherwise -- sunlight is an important requirement for ferrets,
one necessary to produce the vitally important nutrient, vitamin D. I
would think the purposeful blocking of sunlight from ferrets would be
dangerous without strong empirical and peer-reviewed evidence to back
up such a suggestion.

There is one other thing I should mention. One of the more serious
aspects of females going through menopause is, of course, osteoporosis.
Neutered ferrets, especially females, have the same problem, and I
already have the data to support that statement. So, what is the risk
of taking a female ferret, already at great risk for osteoporisis, out
of the sunlight that helps them manufacture the vitamin D that helps
them maintain calcium intake and strong bones? I think it is downright
dangerous. Of course, I would be greatly relieved and happy if someone
could prove me wrong. Until then, my ferrets get as much sunlight as
they want.

Then Shirley rambunctiously queried,
>Bob, do you have any thoughts on these ponderings?

I thought the Pondering-osa was in Nevada...aren't you in Aussieland?
Sorry, if I am confused, but I recently heard a dated recording of
Lorne Greene singing "Ringo" in French. I am still pondering what he
was thinking. It was a ponderous song.

Bob C [log in to unmask]

[Posted in FML 5552]