Wolf quest, a wolf animal mmorpg that shut down cause of lack of state funding.
I'm pretty sure it's still up and running, I think they got funding from elsewhere to keep it running, apparantly people have still been able to get on to the online stuff.
And Geoleo, these are some good ideas, but way too realistic for FH. The heat and mating especially. FH has enough issuesd with people 'raping' people without this, just imagine the hullabaloo with it XD
The hunger and thirst would be irritating, but i do think that being able to eat and drink would be a good idea, just without the hunger and thirst.
Sleeping can already be done, just lay down. AFter all, what else could be added to make them sleeping? It's not like you can just skip to day like in minecraft XD
Excercise can be done through the size and weight and all that bars I'm pretty sure. Having your characters weight change would be annoying if you are using them to RP, or they are a character with a specific weight.
The going toilet thing would definetly be misused.
Scratching trees would be cool though.