Sheep

Classic
0.28: Sheep added, drop mushrooms when killed.

Indev
0.31: They drop Grey wool when hit. They no longer drop mushrooms or eat grass.

Infdev
June 27, 2010: Sheep drop White wool.

Beta
1.2: Grey, light grey, and black sheep were added. Colored sheep drop their corosponding wool color.

1.4: Sheep can rareley spawn as Pink or Brown.

1.7: Sheep drop 2.4 wool when sheared and don't drop wool when hit. They drop 1 wool when killed.

1.8: Sheep flee when attacked.