Probably a really obvious and easy question, but recently I keep seeing/hearing people call horses I would just call bay a blood bay, dark bay etc and I didn't know there were different types of bay. So...is Gem just plain bay or something else? She gets super dark int he winter, but you can still see her black legs. Thanks!
Bay is bay. People are just using different descriptions to describe the shade, but its nothing official. Dark bay or mahogany bay is really dark - almost black. Blood bay are deep red through the body. Copper bays have an orangish tint to them and are a bit lighter.
The one bay that is different is wild bay. When talking about wild bay it indicates a bay with very little black on the legs. Typical bay will have black going to or above the knees while a wild bay will only go part way up the cannon.
Cat is correct: The only bay that is actually different is wild bay. Wild bay is caused be a different form of agouti (the gene that restricts black to "points") than regular bay, so the black on the legs only go up to the pastern, if that.
The other terms (mahogany, blood, etc) are just referring to the shade, the same as calling a very light buckskin "buttermilk". It's not genetically different than a deep golden buckskin, but they just give them different names.