To put the record straight, the original Easter Bunny was not supposed to be a rabbit but a hare. Hares are mostly commonly seen in the spring as the males energetically pursue the females. Their hormone driven pursuits have given rise to the phrase 'Mad as a March Hare'. If you have ever watched a male hare catch the scent of a female you will see how they become possessed and it is a common sight watching them sniff along the ground in pursuit during the Spring.
At this time of year hares will often sit up, as shown in the following photograph, presumably to give them a better view as the look out for females.