So this was meant to be just my headcanon for the differences between the different mer races' ears (size, shape, if they can move on their own, etc.), but there's a tinge of just general visual differences between them in there too (because this ended up being really good face practice for me). I'll mostly talk about ears though. Obviously this is more meant to be general trends than hard and fast rules.
I'll start with the playable races.
Tall and skinny ears that can move out and back a bit (moderate range of motion). They mostly are close to the head but can also stick out a bit.
They have a wide variety of how their ears can be shaped; small, tall, wide, big, straight up, curvy, etc. The typically stick out more than Altmer's and have a larger range of motion.
The largest variety of any of the races. Their ears can look like just about anything any other race has (except maybe Maormer) from any mer ears, to more human ears, to more animal-like ones. They have a large range of motion regardless of how they look.
Small, almost human-sized ears, but they stick out more from the head than humans and can be wider. The pointed end tends to stick out. They can rarely move.
Breton basically just have human ears with a little point at the top. I thought it would be fun to draw a sort of comparison to your average Nede and average Breton to highlight the subtle more merish look that I think Bretons should have too.
Ok now for non-playable races
Ok so I have terminal Falmer brainrot so I have a lot of completely made up headcanons for these guys sorry lol.
Snow elves have the least variety. They are usually shorter and closer to the head than the other mer races (which evolved as an adaptation to counter frostbite in my headcanon) and can't move. Conversely, I like to headcanon that falmer are on their way to evolving rudimentary echolocation, and therefore have huge ears that stick out far from their head, and are very mobile (this is also why their faces are covered in wrinkles). They can look more traditionally merish, or some of them have real funky shapes.
Basically a mix between how the Altmer/Aldmer and current Dunmer look (both in their general appearance and ears). Think of it like the transition between the Aldmer look and Dunmer.
Dwemer have relatively short ears (compared to other mer) and don't stick out much, but they can be wide along the side of the head. Their shape is usually pretty angular and have limited mobility.
Your standard pointy fantasy elf ears. So I technically headcanon the Aldmer as many different (although similar) groups that are referred to as one group due to the nature of retelling history and some propaganda sprinkled in there, but in general, since the other mer of Tamriel descended from them, I see them as sort of generic. Nothing particularly notable in their ears. Minimal to moderate ability to move them.
Curvy. They have Aldmer sized ears with twisting and curving in different directions. Limited movement, and not too much range in size (just shape). I have 0 reasons for thinking this, I just thought it would be fun and unique and maybe fit their aesthetics.
I like that canon Maormer ears look fin-like but I want to turn it up to 11. Large variety of shape and size, but usually large and fin-shaped as a general trend. Huge range of movement.
They aren't elves, but they are described as human/mer-like, so I figured I'd include the Ohmes. They usually have pointy, mer-esque ears, but less distinct than most mer. Despite being relatively small, they have a wide range of movement for their size (and move in similar ways to the way cats ears move for the rest of the Khajiit). They can be extra fuzzy or have little tufts at the end for Ohmes-raht.
