I do see your point, but I don't agree with the analogy. Mammals and reptiles are very different metabolically.
I don't know if there would be any way to tell purity or not based on appearance and size.........personally, I buy what I like
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I might have a more strict opinion if they were actually two different species I guess........
Your final statement sums it up well and I agree fully
I hope I didn't offend you Trevor, I was just offering my opinion
JonK