An investigation at Calgary Zoo in Calgary, Alberta, found that an otter died because of a pair of pants dropped in its habitat.
The Canadian zoo said that two zookeepers have been disciplined for what they said is an "unauthorized enrichment item."
"It was determined that an unauthorized enrichment item, a pair of pants, had been given to the otters by a zookeeper," the zoo said in a statement. "The necropsy revealed that the otter drowned after becoming tangled in the pants."
CNN reported that despite efforts of a zookeeper, Logan, a 12-year-old North American river otter, died.
The zoo said they could not give any more details on specific disciplinary action because of privacy.
According to the zoo, each animal has an approved list of what enrichment items are authorized.
"Enrichment items can be food, new smells, or physical items that adds to the day of an animal," the zoo said in a comment on Facebook. "They are used as stimulants allow animals to problem solve, play, experience new tastes and aims to keep them mentally enriched."
Calgary Zoo has had other unusual animal deaths in the past.
CBC News reported that in 1993, a polar bear named Misty died after being prescribed the antidepressant drug Prozac to control what the zoo said was erratic behavior.
In 2008, a female capybara was crushed in a hydraulic door. A zookeeper was suspended for not following proper protocol when transporting the animal to a different enclosure.
In 2013, Fiona the penguin died from internal bleeding eight days after swallowing a nearly foot-long stick. The zoo called it a freak accident after surgically removing the stick.
"This error is unacceptable," the zoo said at the end of their statement about the otter death. "Our animal care protocols are among the most stringent in the industry and must be followed. We will be reinforcing our protocols with every member of our Animal Care staff to prevent an incident like this from ever happening again."
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