How Do You Measure ?

Apocalypstick said:

I have done a search and this has been dicussed in a topic recently, but I want an overall picture of how people measure thier Ts. This includes exuvium and/or the T itself ...do you measure your OWs and meanies while they sit around

If you would, I'd appreciate a post stating your reasons why you feel your way is best for all to use...be it because the "bible" tells us so or because of your own logical reasons.

Thanks, Becky

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metallica said:

i vote C: body length

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metallica said:

i vote C: body length

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Elizabeth said:

Here's a link to another AB thread. Notice post #6 from Windchaser: the diagonal in an "at rest" position is the standard:

http://www.arachnoboards.com/ab/showthread.php?t=41603&highlight=correct+measure

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Lopez said:

Diagonally makes far more sense than tip to tip.

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Vys said:

Why is that?

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Apocalypstick said:

That was a good discussion Wind... justification for both methods

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> Recently a discussion has appeared on one of the enthusiast web sites that
> pertains to measuring tarantulas. I am reasonably sure that the recommended
> method is to measure from the tip of leg I to the tip of leg IV on the
> opposite side.


I quote here a passage from an upcoming book that we're close to
finishing ...

**********************

The Size of the Matter

One recurring topic of discussion concerning tarantulas is the matter of
size. How big is the world's largest tarantula? It turns out that this is
an unexpectedly difficult question to answer. (But then most aspects of
spiders in general and tarantulas in particular are unexpected!)
Complicating factors include such things as differences in obesity and
hydration, sexual dimorphism, and interspecific differences in body
habitus (relative proportions). While an extensive discussion of the topic
is inappropriate here, we will cover a few of the high points.

Probably the most commonly used measure of a tarantula's size is its leg
span and this is generally defined as the distance from the tip of leg I
on one side to the tip of leg IV contralaterally (on the other side).
There are some major problems with using leg span. The most obvious is
that the males of most species have longer legs than their corresponding
females. Is the male goliath with a thirty centimetre leg span really
larger than the female with only a twenty-five centimetre leg span in
spite of the fact that she may outweigh him two to one?

The other problem with leg span is the very practical problem of actually
measuring it. What exactly do you mean by "leg span?" Does one measure the
absolute maximum leg span or the leg span as the tarantula rests in its
normal posture? The two values are likely to be quite different and the
"resting posture leg span" will be highly variable, depending on the
varying posture of the tarantula. This would invalidate any comparisons
between different individuals or even with the same individual over time.

The absolute maximum measurement also is fraught with difficulties. First,
because it requires handling or manipulating the tarantula, something many
of us are hesitant to do, especially with one that's the size of our face
and that may have a bellicose attitude in addition! Secondly, to get the
maximum leg span one must at least flatten out the tarantula. This is
bound to require two handlers (or more!) if for no other reason than that
the tarantula will not appreciate this abuse. Thirdly, one must decide how
much tension to put on the legs while measuring. The leg span of a really
big tarantula may be increased by as much as a half-centimetre or more
with just mild tension. Great care must be excised not to pull the leg
off, however! Is stretching the tarantula's leg fair and honest?

Occasionally enthusiasts will report the leg spans of dead tarantulas.
This may also be unfair because with death, the tarantula loses muscle
tone, allowing the leg to stretch an amount not possible in life.

Another common measure is weight, but this is also fraught with
difficulties. In a given species, the female almost always outweighs the
male, even though he may have a longer leg span. Is the male or the female
the larger?

Also, a tarantula's weight, strongly dependent on feeding and hydration,
may vary widely. It is possible for a newly imported tarantula to be only
half the weight of a well fed, arguably obese one that has been in
captivity for years, even if both have identical leg spans.

Dr. Sam Marshall (Marshall, 20001) has suggested using the length of the
femur of the front legs as a good measure by which to compare tarantulas'
sizes. This is probably a much better measure than any other because this
dimension would not vary appreciably depending on the tarantula's state of
obesity or hydration. However, it still carries major problems when
comparing animals of different sex or species. Also, one must admit that
stating that one's tarantula has a 4.67 centimetre femur length just
doesn't have the same impact as stating that it has a thirty centimetre
leg span!

Ultimately there is no perfect ruler to use and the enthusiast is warned
to always state whether leg span, body length, body weight or some other
measure is being used. And, when another enthusiast states a size without
making that distinction, it should not be considered bad manners to ask
for a clarification.

**************************

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Windchaser said:

Take a look at this thread: HERE. Apocalypstick and I had a discussion regarding this very topic.

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Vys said:

Thanks, quite interesting.

It was mainly Lopez way of putting unjustified things that irked me.

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