Can You Tell Which Horse This Head Belongs To?

One Bored Panda reader has just sent us this picture of the 'Tell The Horse Heads Apart Challenge' - can you guess which horse the head belongs to? We're not sure if this is some kind of personality test, or something that checks how resistant you are to optical illusions...

One thing is for sure - you bet you'll have to look twice or thrice at the photo to get the right answer. We can't figure it out ourselves, so please help us out by sharing your opinion in the comments below.