Recent Posts


Are “Frozen Zoos” the Future of Endangered Species Recovery?


WCC collecting Mexican wolf semen with Dr Asa

Critically endangered Mexican gray wolves roam the wilds of New Mexico, Arizona and Mexico. They also live in captivity. But their future may lie in a “frozen zoo.”

That’s the term of endearment scientists use for the bank of frozen wolf sperm and ovaries stored in cryogenic vaults where some of the most precious genes of the species are being held for future reproductive use.

Although the “frozen zoo” is great tool to preserve rare Mexican wolf genes for future use, other recovery strategies need to occur immediately to rescue the wild population from the brink of extinction – we need to prioritize captive-to-wild release events. Unfortunately state politics have too often blocked U.S. Fish and Wildlife Service’s (USFWS) release efforts, so wolves essential to the genetic health of the wild population remain in captivity. The Service has a responsibility under federal law to facilitate recovery of the critically endangered species and releases are a central part of that effort.

Only ten wolves, including six pups fostered into existing wolf dens earlier this year, have been released from captivity since 2009.

Michael Robinson of Center for Biological Diversity agrees that too few genetically valuable wolves are being released from captivity into the wild. “If these wolves had been released a decade ago, instead of stuck in pens due to politics, their great-grandpups would roam the Southwest today, embodying the genetic diversity that instead is being stored in freezers.”

Are “frozen zoos” the future of endangered species recovery? How do you feel about this?


The Mexican gray wolf (Canis lupus baileyi) or “lobo” is the most genetically distinct lineage of wolves in the Western Hemisphere, and one of the most endangered mammals in North America. By the mid-1980s, hunting, trapping, and poisoning caused the extinction of lobos in the wild, with only a handful remaining in captivity. In 1998 the wolves were reintroduced into the wild as part of a federal reintroduction program under the Endangered Species Act. Today in the U.S., there is a single wild population comprising only 97 individuals – a decrease from 110 counted at the end of 2014.