The Lincoln Park Zoo has paid a $3,000 fine after federal authorities ruled it was to blame for a gorilla attack on a zookeeper and for the deaths of several langur monkeys last year, officials said Tuesday.
The U.S. Department of Agriculture said the fine was imposed in February and the zoo paid it promptly.
"The matter is considered closed by the USDA" and there are no further investigations of the Lincoln Park Zoo, agriculture department spokesman Darby Holladay told the Chicago Tribune.
Scrutiny of the zoo began after a series of deaths over the past two years.
The deaths included three elephants, two gorillas and a camel - incidents that led to protests by animal rights groups outside the zoo.
But the USDA's Animal and Plant Health Inspection Service only held the zoo responsible for the gorilla attack in July 2005 and for the deaths of the three Francois langur monkeys in May of that year.
The zoo did not have proper barriers in place at the gorilla habitat and it didn't have adequate enclosures for the monkeys, the USDA spokesman said.
"They followed all regulations regarding all the other animal deaths," he added.
Lincoln Park Zoo spokeswoman Kelly McGrath said the three monkeys died after they ate leaves from a yew tree just outside their habitat.
"We knew a mistake had been made, and we immediately removed the plant not only from the exhibit but from the zoo grounds," she said.
An employee's error led to the zookeeper being bitten by the gorilla, she said.
But the head of People for the Ethical Treatment of Animals said the action suggests other animals at the zoo could be at risk.
"The fact that the zoo was fined - a rarity, to say the least - for failing to maintain the woefully minimal standards of the Animal Welfare Act does not bode well for the animals who still live there," PETA director Debbie Leahy said in a statement.