His formal name is Enoki SunRat's Boy, and he is a fancy rat, specifically a standard, teddy rex, agouti, self coat. The rex gene gives him the curly fur, and those silly curby whiskers!
Enoki is a gentle giant - he is the biggest in the pack of four rats I have, all boys, and his character is wonderful. He is also very clumsy and this makes the impression that he is fool, but he isn't. He can do the best spins, too - and just looks so joyful when he does them! His fur is as soft as a plush, I often called him "Mascot."