Q:(Several questions condensed to one) How can you age a ferret?
A: I card 'em, and if they aren't 21, no Fat Weasel Ale! More for me!
Trying to figure out the age of a living (or dead) ferret is difficult at
best, and impossible at worst. The problem is, since the ferret is an
unknown, so are those factors which create variation (or deviation) in the
areas used to estimate their age. Complicating things is that while wild
animals tend to be born roughly about the same time (each spring, for
example), pet ferrets can be born year-round, so even using such ordinal
scales like "Spring 1998 Cohort" can be considerably wrong.
There are four basic ways to age a living ferret; behavior, body condition,
skeletal ossification, and teeth. You can add a fifth for male ferrets,
the size of the base of the bacula. I try to use all possible methods for
each ferret, and sort of "average" the ages for my guess.
Behavior is the worst way to estimate age. It is based on the idea that as
a ferret ages, it will pass through stages of behavioral development, which
can be used to estimate it's stage of life. While these basic stages tend
to follow set ages [newborn (0-1 month), kit (1-3 months), juvenile (3
months-1 year), young adult (1-2 years), middle aged adult (2-4 years), old
adult (4-5 years) and geriatric (5+ years)], the amount of variation that
exists within individual ferrets makes it impossible to be accurate. It
can give you a rough guestimate, but nothing more. Unreliable.
Body condition is just as bad. It is based on the idea that the body
changes in tone and composition as it ages. In other words, older ferrets
have older bodies, and once you can tell the difference, you have a very
rough idea of the age of the ferret. The problem is, just about anything
can influence the condition of a ferret, throwing off the estimation.
Sickness or injury can change a ferret's behavior. Unreliable.
Another way to estimate age is by the degree of ossification of the
skeleton (you know, a bunch of bones with the ferret scraped off). As the
ferret ages, bones tend to grow together and fuse; each bone tends to do
this at a specific time, so seeing the skeleton allows a pretty good idea
of the age. In living ferrets, this can be used, but the ferret tends to
ooze down drains. No, just kidding. In living ferrets the technique uses
X-rays, which show the degree of ossification even better than by the
neckid eye. Needless to say, this way of age estimation is not normally
used by most people. Also, the ferret matures at a year of age, and the
skeleton fuses pretty quickly after that, so this method is not good with
ferrets older than a year or so. Very reliable to a year of age.
In males, the bacula can be used to estimate age. With ferret skeletons,
you can easily see the size of the base of the bacula, or weigh it, and
come up with a good estimation of the age. The bone grows slower than the
rest of the skeleton, so size of the bacula helps to age the ferret. Also,
the ligament which attaches the bacula to the pelvic bone tends to ossify,
making the base larger over time. In living ferrets, you can molest, eh, I
mean test the size of the base of the bacula using your thumb. The base is
on the tummy side almost at the anus; just find the pelvis at that point,
and press your thumb gently down. If your ferret is a male, you will feel
the bacula as a hard ridge running down the belly, and the base of the
bacula as a bump on the ridge. In early neuters, the base of the bacula
will only be about 1/3 to 1/2 the size of late neuters, and hobs will even
be slightly larger. Very reliable if ferret history is known.
Teeth are often the most accurate way to age a living ferret. Three
techniques are useful in living ferrets; tooth eruption, tooth wear, and
tooth transparency. Tooth eruption is the sequence in which the baby (or
milk) and adult teeth drop in, and is useful until the ferret gets about 3
months old when all the permanent teeth should be erupted. The sequence
of tooth eruption (from birth) is: Incisors: Deciduous (Baby): 0-10 days;
Permanent (Adult): 20-30 days. Canines: Deciduous: 20-30 days; Permanent:
45-55 days. Premolar 2: Deciduous: 28-40 days; Permanent: 55-65 days.
Premolar 3: Deciduous: 28-45 days; Permanent: 55-65 days. Premolar 4:
Deciduous: 28-50 days; Permanent: 55-65 days. Molar 1: Permanent: 48-55
days. Molar 2: Permanent: 70-80 days. As you can see, considerable
variation exists. Reliable to 3 months of age.
Tooth wear is useful for aging, but only allows you to decide if one ferret
is older than another. Kibble causes teeth to wear at a much faster rate
than in animals that eat a more natural diet. The best teeth to look at
tooth wear are the cutting molars or carnassials, as well as the little
molar in the back. Very rough estimate of age. Unreliable.
Tooth transparency is a natural adaptation which allows tooth wear or
fracturing without exposing the root. As the ferret ages, the root canals
fill with dentine (making the tooth solid), changing the way light shines
through it and making it appear transparent. The best tooth to use is the
canine; it will be approximately half transparent (from the tip up) when
the ferret is 5 years old. This is only a rough estimate, because tooth
use and stress determines the rate of root withdrawl, and nutrition
determines the rate of canal filling. It is easy to be off one or more
years using this method. Marginally reliable.
If you have been paying attention, you will realize it is extremely hard
to age a ferret that is older than a year or so. How do scientists age
animals so well? By pulling a canine, slicing it, and counting the rings
of cement on the root, which are more or less laid down seasonally in wild
animals (little research has been done with pets). I don't recommend
this method to age your ferret. ;-) But even with the difficulties I've
discussed, with practice, and comparisons to known-age ferrets, you can
estimate fairly well. At least to within a year. Maybe.
Bob C and 19 Mo' Fanged Ferts of Ferretdom
[Posted in FML issue 2635]
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