Cathy Gaviller, who spent two decades with the Calgary Zoo before resigning this week, is shown speaking to reporters in December. (CBC)

The head curator at the Calgary Zoo has resigned, days after a gorilla almost escaped from its enclosure.

Cathy Gaviller, the zoo's director of conservation and research, resigned this week after 20 years at the facility to "pursue other opportunities," officials said Thursday.

"I am very proud of what we have achieved at the Calgary Zoo and of my contribution," Gaviller said in a statement.

"The past few months have been very challenging for the organization and for me personally. I care deeply for the Calgary Zoo and hope my decision can help the zoo move forward confidently and begin a new chapter in animal stewardship."

Zoo spokesman Simon Scott called Gaviller's resignation a loss.

"Nevertheless, her decision will enable us to refresh our leadership and inject a renewed sense of focus into excellence in animal stewardship," he said in a statement.

Zoo under independent review

Gaviller's resignation comes the same week that a zookeeper was suspended for failing to properly check an outdoor enclosure where ice had built up in a moat. A gorilla was able to jump from the ice to a perimeter fence, where it perched for several minutes before returning to the enclosure.

The zoo is currently under an independent review of its animal care practices after a capybara, a large South American rodent, was crushed to death by a hydraulic gate.

Several other animals have died at the zoo in the past few years including a baby elephant, a hippo, a wild goat, four gorillas and more than 40 stingrays.

Last month, two non-poisonous snakes escaped into a drain inadvertently left open by a zookeeper. They were later found in the drain just below their enclosure.