Two good Samaritans tried for nearly six minutes to get the otter off the man, Morrell Denton, kicking and yelling at the animal while a 911 operator listened and tried to assist.
A Sarasota County sheriff's deputy finally shot the otter dead.
Denton suffered numerous cuts and bruises. One of his rescuers, Christopher Janssen, was also bitten by the otter.
"I kept trying to get him off me," Denton said of the rabid animal. "It's like nothing I've heard of."
Denton was just past the halfway mark of his walk, circling back in the dark along a wooded stretch of Venice East Boulevard near a lake, when he saw something dark emerge from the woods.
"I thought it was someone's pet," Denton said.
The otter "grabbed me by the foot and pulled on my leg and I went down," he said.
Denton was writhing on the ground and bleeding while trying to pull at the otter's ears and head to get him off, but the animal continued to bite.
Raymond Duval, 53, was driving past in his white truck when he saw Denton on the ground and called 911.
The 11-minute 911 recording chronicles Duval kicking the otter and swearing at it and Janssen stopping to help.
"There's a man on the ground with an otter on him," Duval told the emergency operator about 4:30 a.m. "He's lost a lot of blood."
"This otter is nonstop," Duval told the operator. "Please hurry."
One of the rescuers finally struck the otter with a shovel.