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Message:
Subject: To Jane
Posted by Dr. Curtis Mittong on August 30, 1998 at 23:39:12:
In Reply to: Re: To kim posted by Jane on August 30, 1998 at 17:50:53:
: Kim all the stories I have heard the gliders stealing were not preganant so to insinuate that teh glider is trying to raise them is slightly niave. they only steal them to eat them. I have never seen anyone suggesting otherwise. If you have proof a non mated glider looked after anothers abbies fibne otherwise please dont hide what is just one nasty point we have to accept about the glider colony biology. I couldn't help but overscan these last few posts. Holding a PhD in Animal Biology, I feel it may be necessary to introduce some fresh facts into this discussion. What Kim conveyed in a recent post that Dominant female Gliders will remove embryos from the subdominant mother is quite true. The reason for this is what is called a post-genotypical passive natural selection, in which the evolutionary trend is carried on in a non-direct fashion. The net result is strictly that the weaker female is denied the opportunity to pass on her "weaker" traits. The converse, and another of three types of selection is post-phenotypical sympatic selection, as outlined by the Petaurus breviceps behavior here. Although the outcome is the same, the reason is due to a phenotypic ramification, as opposed to a genotype defect. In my studies at the Perth Institute for Veterinary Medicine in Perth, Australia, I observed many behaviors in marsupials, NOT including cannibalism. It is a biological constant (one of the few) that a closed-system community will practice cannibalism after the population density reaches a point near 17 times its normal concentration (versus many variables including body mass/brain mass ratios). Such behavior just doesn't happen in this situation, especially in marsupials. Rodents do consistently practice cannibalism, which is why we scientists use them for so many behavioralist inquiries.
If you have Gliders eating other gliders, it is an unmistakable sign that there is a deeply seated genetic defect causing abnormal behavior and this Glider should not be bred, OR, you have way too many Gliders in a small enclosure. What you describe as "...just one nasty point we have to accept..." and "only reason they steal...is to eat them," are actually the naive statements in this post. The pilfering Glider in the scenario does not steal them to raise them. They have no idea why they steal them. No animal (other than human...sometimes) knows why they do what they do. Have you ever caught yourself doing something you didn't think about doing...just happened naturally? You personify Gliders as logical beings, when in fact, Natural Selection has predisposed their instincts and "tells" them, pregnant or not, to steal the babies to "raise" them. This behavior is reflected in almost every animal Phylum, including the upper Primates which are [arguably] nearing human intelligence. The fact that the babies die is the whole point and definition of post-phenotypical sympatic selection. The point is not whether or not the action has logic, as much as the outcome. Let me introduce an analogy: Let's say you are a serial killer. You have been genetically predisposed for a psychosis, leading you down a path that will more likely than not find you in an electric chair where you won't have the ability to pass on your genetic material. The law "killed" you because you didn't fit the norm and had a destructive quality. The net outcome is a form of natural selection; You didn't get to breed, and pass on your defective genes, but that's not why the law killed you. Understand? The glider passively kills the weaker-genotype embryos, but it is in an attempt to accomplish something else. A+B=C. The net result is the same. It is not a logic thing, it is an action/reaction thing. To say Kim is "naive" is a bit hypocritical. Your statement is based on a personal inference gained through a human perspective. Start looking at things more globally, and open your mind to new possibilities that you may have overlooked before. Gliders do in fact eat other gliders...its going to happen, but Gliders steal babies to fulfill a predisposed instinct. Period. Dr. Curtis Mittong, Ph.D.
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