These words, hybrid and intergrade, are terms that have a specific meaning in the field of evolutionary biology. However, outside the field, they are often used more broadly, and in fact, synonymously.
In biological terms, a hybrid is a natural cross between two different species. An intergrade is a naturally occurring cross between two different subspecies or races.
Now, once you take these snakes out of the wild and put them in plastic boxes, the terms lose their meaning as they aren't "naturally occurring" crosses. So it really doesn't matter.
This kind of non-scientific expansion of terminology is common in the herp trade (for example, my snakes are currently brumating for the simple reason that snakes do not hibernate). This sort of (mis)use of scientific terminology is common in "lay" science.
The fact is, as long as we know what we are talking about, who cares if you call it a hybrid or an intergrade. It technically isn't either since it happened in a Rubbermaid container.
This sort of "expansion" of the meaning of a term does no harm. The only harm is done when someone tries to impose on meaning of the word on the other group.
For example, when someone criticizes the Theory of Evolution because "it's only a theory", they are simply demonstrating their ignorance about the two uses of the word theory. The reason....the word theory has a very different meaning in science than it does to the non-scientist. The Theory of Evolution is only a theory in the same way that the Theory of Gravity is, yet I'm not worried about floating out of bed tonight!
There is no problem with there being two (or more) implications about the meaning of a word (hybrid, intergrade, hibernate, theory, etc.) as long as you understand what it does and doesn't imply in that context and don't try to extrapolate one meaning into the other context.
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Chris Harrison