Re: Interesting topic, Terry....>

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Posted by Terry Cox on January 14, 2003 at 07:10:14:

In Reply to: Re: Interesting topic, Terry....> posted by Phil Peak on January 13, 2003 at 20:40:23:

:Interesting topic. Another species that come to mind is the black pine. I have wondered what enviromental pressures may have been involved for this snakes appearence.
:Another snake would be the eastern hognose. I seen six adult specimens in the field this year from three different county's in Ky. All of these specimens were melanistic. I have seen others from the same areas that were not, but this trait is common. Like the black rat, they the melanistic hogs also start their life as patterned snakes, but as they grow, an ontogenetic change occurs, and those specimens predisposed geteticly to turn black start doing so. Why some specimens in a population go through this color change, and others do not interests me.

Some nice observations there, Phil. I discussed the black pines above, so will just take a look at the melanistic hognose here.

I have also seen several black hognose, but in s. Indiana. I have very little experience in KY. The ones I have seen have come from areas that were very hilly and quite forested. I believe these are environmental factors which influence the melanism in black rats also.

Why some populations are all black and some are mixed with melanistic individuals, is a very interesting situation. I think, genetically, in the all black pops. that the melanistic gene has taken over, i.e. no normal gene is present. In the other pops. both the melanistic gene is present and the normal gene. When the normal gene is present, the offspring will look normal, but could be het. for melanism. When both parents contribute the melanistic gene, the offspring will be black.

It's the old Mendelian explanation, I know, kinda simplistic, but it's the only thing I can think of at present. One thing hobbyists have going for them is that they're in the business of breeding snakes, so to speak. Obviously we can experiment with different situations involving genes. We need to remember too that snakes that we buy captive bred could have already been experimented with, and who knows how many kinds of genes they are carrying. That's one of the reasons I work with some wild caught too, and am very careful about what and who I buy anything from.

Thanks for the input, Phil. Later.....TC.

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Re: Interesting topic, Terry....> Phil Peak 01/14/03 (0)