Why are my dreams so vivid?

Every night my dreams seem to come more real and real. I can hear,smell,taste etc.. I can feel textures and experience emotions. The people and the places in my dreams are so clear and sometimes its hard to distinguish whats real and whats a dream. I just dont understand how this is possible. Ive heard alot of people talk about they usually cant remember dreams and if they do most of everything is grey. As soon as I wake up I can remember exactly what had happened in my dreams. I remember dreams from when I was a child being just as vivid. Ill give one example, I was standing in a gry field but the sky was kind of a grayish black. I look down and see a tombstone with no name and then I look of to the right and see a huge but dead oak tree. I knew the tombstone looked identical to my grandma's but when i looked back at the tombstone there was a crow sitting on top of it. I stuck my hand out and the crow stepped out on to it and i thought to myself this is a friend it had a good vibe. When the crow stepped out onto my hand it licked each finger individually just one time and then looked up at me and my dream stopped. I could feel his claws pushing my hand and the small tongue licking my finger i mean everything. Please if somebody has an answer help me with this.