Posted by:
Tony D
at Tue Feb 2 12:52:51 2010 [ Email Message ] [ Show All Posts by Tony D ]
feed schedules
I have long thought about the growth "potential" of snakes and Frank's post below got me thinking about putting some of those thoughts here to see what you all think.
My first thought is that "growth potential" falls into two distinct categories. In the first sense growth potential refers to the maximum achievable length. This is the terminal length that an animal can achieve. This potential is dictated first by genetics inherent to the species and then to the individual. In other words not all specimens within a population have the same maximum size. If you could plot the inherent potential of every animal in a given population you'd likely see that they all fall within a pretty predictable bell curve around the population average. Some animals will max out smaller and some will have the potential to be significantly larger than their counter parts.
In the second sense growth potential refers to an individual's capacity for growth throughout it's life time. Based on my observations this potential is not constant throughout the life span of the animal. Younger snakes, neonates in particular, have tremendous potential for growth in the first year of life. As snakes ages however their growth potential gradually diminishes until it reaches a base level needed to maintain proper function.
It has also been my observation that animals who are not supported for maximum growth in the first year of life experience a corresponding decrease in overall maximum growth potential. In other words they loose it. This is how the two potentials relate or combine to account for total growth potential. For example, if Frank and I both raise a pair of thayeri picked from the same clutch, at the end of the first year Franks's pair lets call them pair A are 24" each and my pair (pair B) are 18" each. Frank's pair A may go on to grow to much larger adults even if my pair (B), as individuals had the higher inherent potential. If Frank and I had started with the opposite pairs (he had B and I had A) our 12 months results may have been 30" and 16" respectively with the same inputs. I'm not sure if that's clear but that's about the best I can describe it.
The implications here are pretty clear. If you expect to successfully raise animals as breeders you must give enough feed during the early years to sustain appreciable growth otherwise they may loose the capacity to get to the size required to support reproduction. Clearly, for younger actively growing snakes more food is better.
The problem comes in with adults. Here a smaller adult may be seen as still having additional growth capacity when in fact he's just maxed out at a smaller size. Heavy feeding of such a snake is likely to result in obesity. Like wise an averaged sized adult that is assumed to be maxed out may actually have a higher inherent potential for growth and actually loose weight and vigor on a less liberal diet.
In nature selection pressures weed out those animals that are not best suited for survival at any particular time. During years of abundance snakes with low growth potentials may become obese, less agile and subjected to increased predation. During lean years, those with metabolisms that put them at the high end of growth potential may not be able to acquire enough food to support personal growth much less reproduction. In the end its this type of variation within the population that ensures that at least some members will be successful in a wide range of conditions.
As captivity lacks any real selection pressures we have to gauge our animal's conditions individually and sometime make some choices for them. This is particularly true if your feed regimen is at the extremes of what will generally work. Under power feeding regimes, some snakes with low inherent growth potential will undoubtedly get fat. On the flip side if one keeps animals on a slower growth/maintenance track, a specimen that is seen to not be thriving may just have a higher inherent growth potential and metabolism and is simply not getting enough food even though its counter parts are. Viewing such animals as poor performers is in my view is misinformed at best and cruel at worst.
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“Nothing is at last sacred but the integrity of your own mind.” Emmerson
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 Growth rates and the implications of.... - Tony D, Tue Feb 2 12:52:51 2010
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