The tag implication #41565 butt_heart -> countershade_butt has been rejected.

Reason: butt hearts form as a result of countershade butt (not all butt countershading forms a heart though)

EDIT: The tag implication butt_heart -> countershade_butt (forum #317076) has been rejected by @bitWolfy.

Countershading said:
A lighter belly / front region than the rest of the body.

Countershading is a form of camouflage and is often thought to have an adaptive effect of reducing conspicuous shadows cast on the ventral region of an animal’s body. In essence the distribution of light on objects that are lit from above will cause unequal reflection of light on a solid body of uniform colour; such shadows could provide predators with visual cues to a prey's shape and projection. Countershading therefore reduces the ease of detection of prey by potential predators by counterbalancing the effects of shadowing.

I don't think a heart shape in any way helps to camoflauge the butt. If anything, it makes it more noticable, which is very much the opposite of countershading.

In an alternate means of defining it:

Wikipedia said:
Countershading, or Thayer's law, is a method of camouflage in which an animal's coloration is darker on the upper side and lighter on the underside of the body.

This, in particular, provides an interesting difference. It is impossible to call it a heart if it's countershaded, because the heart shape would retain the same color throughout. That would fall under butt_markings.

I disagree with your changes to the butt_heart wiki as well as this implication.

A butt heart isn't necessarily a lighter color than the surrounding fur/scales/whatever. It's not even necessarily a different color (there could just be a line between two areas of the same color).

furrin_gok said:
I don't think a heart shape in any way helps to camoflauge the butt. If anything, it makes it more noticable, which is very much the opposite of countershading.

I don't think whether or not the countershading makes sense in an evolutionary context actually matters for tagging purposes lol. The presence of a patch of fur lighter in shade (or darker, if tagged in tandem with dark_countershading) than the rest of the body is the essence of the tag.

deleuzian_cattery said:
I disagree with your changes to the butt_heart wiki as well as this implication.

A butt heart isn't necessarily a lighter color than the surrounding fur/scales/whatever. It's not even necessarily a different color (there could just be a line between two areas of the same color).

Fair enough.

The tag implication butt_heart -> countershade_butt (forum #317076) has been rejected by @bitWolfy.