A dispatcher told the young man that paramedics could not come to his aid until they could be sure they weren't in danger of being attacked themselves, according to the recording.
"It's a matter of life and death!" the young man shouts minutes into the call.
"I understand that, but at the same time we have to make sure the paramedics don't get chewed out, because if the paramedics get hurt then nobody's going to help you," the dispatcher replies.
Seconds later, the man shouts, "My brother's about to die out here!"
The 911 call came from either Paul or Kulbir Dhaliwal, though it wasn't immediately clear from the recordings which one.
The brothers were attacked, along with their friend Carlos Sousa Jr., outside the tiger's enclosure on Christmas Day. Sousa, 17, was killed. The Dhaliwals were severely injured.
Zoo officials say the tiger climbed or jumped over the wall surrounding its pen. They've acknowledged the wall was four feet shorter than the recommended minimum.
The recordings reveal intense fear and frustration by the young man, as zoo officials and emergency responders scrambled to understand what was happening.
Less than 60 seconds into the nearly 7-minute recording of the conversation between the dispatcher and the young man, the escaped tiger had already killed Sousa, and the brothers were frantically looking for help.
According to the recording, the 911 dispatcher tells the man to calm down before the frustrated caller asks, "Can you fly a helicopter out here? Because I don't see a (expletive) ambulance."
The recordings also reveal disbelief of the circumstances by zoo employees.
An unidentified male zoo employee who was on the opposite side of the tiger's enclosure from where the three friends were attacked called 911 at 5:05 p.m. to relay a report from a female zoo employee who encountered the frantic brothers outside a snack bar.
"I don't know if they are on drugs or not," the woman employee is overheard saying over a colleague's walkie-talkie. "They are screaming about an animal that has attacked them and there isn't an animal out. He is talking about a third person, but I don't see a third person."
Attempting to translate her remarks to a 911 dispatcher, the man said, "He was saying he was bitten by an animal, but there is no animal escaped so he could just be crazy."
The female employee on the walkie-talkie interjects: "He is saying he got attacked by a lion," to which the man replied, "That is virtually impossible. ...I can't imagine how he could have possibly gotten attacked by a lion. He would have had to have gotten in. I just can't see it."
"I think this guy is on something. He is really agitated," the woman said.
"They don't know if he got attacked by a lion. They are both very agitated and they might be on drugs," the man told the dispatcher.
At 5:10 p.m., five minutes after the first 911 call was made, word reaches the male employee that an animal was loose. He starts telling other visitors that they must leave the grounds immediately.
"We have a code one. They say they have a tiger out," he told the dispatcher.
A lawyer for the Dhaliwals has said help did not reach the men for more than 30 minutes after they first reported the attack. Zoo officials have said that zoo personnel behaved heroically during the tiger escape crisis.
The extent of Sousa's injuries became known at 5:15 p.m., when either a paramedic or another zoo employee is heard over the radio reporting a fatality.
"This person needs help now," he said.