Heating Pads
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Someone suggested using reptile heating equiptment to warm your fuzzies.
Just a warning: some of these products get friggin' hot!!! Those of you
that keep herps and frequent rec.pet.herps will be aware of the on-going
political battle re: hot rocks. These products can cause thermal burns on
reptiles, and some people think that they should not be sold at all.
Both Zoo-Med AND Tetra-Terrafauna make models of fake rocks with built-in
thermostats. The "Repticare Heater" and "Sizzlestone", respectively, come
with the thermostat option. These companies, and several others, also make
heat pads, though finding a pad with a thermostat, for some reason, is
harder. Heat pads should not be used without some sort of covering over
them (and I don't mean your fuzzy!) to protect your pet. They can cause
burns.
If you are buying a reptile-specific product, I agree: GET ONE WITH A
THERMOSTAT, OR ADD ONE ON. There are lower operating temperature, mammal-
specific heating pads on the market as well.
For a good selection, check out Valentine's (1-800-GET-STUF in the U.S. and
Canada). Valentine sells a "Bunny Saver" for $20...haven't tried it, but
this may do the trick.
Colour Vision
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"How do they *know*?" seems to be the big question these days. This isn't
the definative answer, but it's a start.
There are several types of cells found in the retinas of vertebrates: cones,
rods, double cones as found in herps...the cell types help give a general
idea of what the animal can possibly see.
Cones allow colour vision and definition, or "sharpness" of vision.
Rods allow low-light, less defined, "greyscale" vision.
There is only so much room for cells in the retina. An animal like a cat
has a large concentration of rods, for night vision...it's a nocturnal
animal. Diural (day-active) iguanas have cones and the reptilian double-
cone, giving keen, full-colour vision. However, they lack rods entirely.
For practical purposes, they have no night vision.
Going back to the cat: cats do have some cones for colour vision, but very
few...thus, poor colour and definition perception. You may notice that you
cat is keyed to movement. They don't rely on their ability to clearly
define objects (not practical) and instead, rely on movement. They also see
best in the centre of their field of vision due to the arrangement of cells.
Humans are diurnal. As you might predict, they have a high concentration of
cones, particularly in the centre of their retinas. The rods are shuffled
off to the sides...night vision is not teribly important to us. A weird
consequence that you can check out yourself: we see things in poor light
better if they are viewed at a slight (say 30 degree) angle.
Birds, the best example among several creatures, have oil droplets that
filter out certain wavelengths of light.
Types of cells, numbers of cells, arrangement and concentration of cells...
all play a part in defining an animal's visual abilities.
Anyhow, can't tell you where, exactly, ferrets fit in, except to say they
must have a high concentration of rods and few cones, like a cat.
As far as "testing" for colour perception...researchers can offer puzzles,
different colours of food dishes, etc, and watch for the reactions of the
animals. Colours tested are all of the same "saturation"...that is to say,
if you were to convert a given shade of red and a a given shade of green,
for example, to a corresponding shade of grey, they would appear the same.
(Like watching colour TV on a black-and-white set...with the exact right
saturation of all the colours, the whole screen would be grey.) Colours are
tested against greys, etc., and researchers then conclude what colours are
actually perceived. (Fuzzy: "Whatdaya mean, press the green button for
raisins!?!? They're all grey!!!) This is the simplest approach...no doubt
other techniques are used.
Sounds like the library's calling me...I will go and see if I can find out
more on Fuzzy vision, pun intended ;-)
[Posted in FML issue 1452]
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