CALGARY - The Calgary Zoo has been subjected to unfair criticism for a string of animal deaths at the facility, president Clement Lanthier told a news conference Saturday.

A little more than a week after a giant Central American capybara was crushed to death when a worker closed a hydraulic door on it, Lanthier said he will commission an independent review of how the facility cares for its animals.

"For the past two years, the zoo has been the target of a great deal of criticism, some of it deserved but much of it not, for the quality of our operation," said Lanthier.

"I have always subscribed to the notion that even a world-class organization can become better if it is prepared to accept and act upon constructive criticism. We are no exception to that rule.

"Sadly, however, much of what I have seen and heard over the past two years has been far from constructive."

The worker involved in the death of the capybara, known as the world's largest rodent, was suspended for two days without pay for ignoring protocol on Dec. 5 while moving the animal.

However, Toronto-based Zoocheck Canada accused the zoo of covering up the death.

Julie Woodyer of Zoocheck Canada noted there was no news release from the zoo until her organization and media outlets were tipped by a worker the following Thursday.

"It's pretty clear they had every intention of keeping it quiet until the tipster came forward," said Woodyer. "Employees don't call Zoocheck Canada unless things are really bad."

Woodyer has called for an independent review at the zoo, which she said has "basically becoming a graveyard for animals."

The zoo has been the subject of controversy for several animal deaths and mishaps in recent years.

Back in January, a Turkmenian markhor got caught in a rope in its enclosure and strangled to death.

In May 2008, 41 stingrays died after the opening of an interactive exhibit where people could pet them in the water. The zoo's president admitted that human error was to blame for those deaths.

This last March, two more stingrays died at the zoo and officials blamed it on a shipping problem.

And in June, there was a furore after a zoo patron snapped a photograph of a gorilla holding a knife that had been accidentally left by a keeper in the gorilla enclosure. Zoo officials said the primates don't understand the idea of using weapons and were never in any real danger.

"By linking together a series of unrelated incidents in an effort to establish some kind of pattern, many of these critics have attempted to further their own agenda of manipulating public opinion and diverting attention away from the vitally important work that zoos, including the Calgary Zoo, do to protect animals and their habitats," said Lanthier.

He said that on Monday, he will contact the Association of Zoos and Aquariums in Washington, D.C., and the Canadian Association of Zoos and Aquariums in Ottawa, the accrediting bodies that set the standards of care for zoos.

"No matter how unsubstantiated or unfair, criticism can raise doubt in people's minds, particularly if there is no objective, independent way to verify the accuracy of that criticism," he said, adding the review will look at all animal care practices and policies.

He said the results of the review will be made public.