Options deemed not viable

Several zoos volunteered to take Marius. The UK's Yorkshire Wildlife Park, which said it has the capacity for an extra male, was among several places that offered to take him.

Copenhagen Zoo said in a Q&A about the decision on its website, "it is not possible to transfer the giraffe to another zoo as it will cause inbreeding."

The EAZA's Dickie said some institutions were ruled out because they did not meet her organization's strict protocols, and the Copenhagen Zoo wouldn't send Marius to an institution with "lesser standards of welfare."

She further said that while EAZA members are "saddened by the death of any animal in our care," the EAZA supports the Copenhagen Zoo's decision and reiterated the zoo's claim that "transfer within our network does not represent a solution to the unsuitability of the individual animal for breeding."

In the EAZA's history, which dates to the early 1800s, its member zoos have put down only five giraffes, Dickie said.

Numerous American zoos did not immediately respond to requests for interviews. The Association of Zoos and Aquariums declined a request, issuing a short statement from executive director Kris Vehrs stating that EAZA's "programs and procedures vary from those of the AZA."

"Through the AZA Species Survival Plan program, these methods include science-based breeding recommendations and cooperating to plan for adequate space," Vehrs said in the statement.

The Woodland Park Zoo in Seattle, Washington, also declined an interview but said its birth plans were managed by the AZA Species Survival Plan.

"With each new animal birth, Woodland Park Zoo establishes a breeding and relocation plan that ensures a healthy and genetically sound future for the individual and species," the statement said.

To claims that the Copenhagen Zoo acted irresponsibly by allowing Marius to be born if it had no room to house him, Dickie said the giraffe was born more than two years ago, and it's difficult to predict "genetic kinship" and a zoo's available space that far out.

As for preventing the giraffes from breeding, that would violate the EAZA's standard of "providing a behavioral repertoire as natural as possible" for animals in captivity, she said.