Jackrabbit Slim
The slope of his back makes me think he is about 3 or 4. When they are young their back slopes down towards the front. When they are old, their back slopes down toward their rump. He looks almost level, maybe sloping forward a little. It's hard to tell from a snapshot though.
Anonymous
Three, maybe four years old. The only way to get a fairly good estimate is to look at their teeth.
John de Witt
It's blurry, but he looks to be probably a 3-year-old.
chris
2-3 years and well fed
JOHN B
I can only see 3 candles on his head and I know there is 1 over his eye so 4 would be my WAG.