The exceedingly rare Amur leopard species gained two new members when a pair of cubs were born at England's Twycross Zoo. (See video below, for a glimpse of the new cubs just after they were born.)

The Amur leopard (Panthera pardus orientalis) is the rarest big cat in the world, with only an estimated 50 or so left living in the wild.

The leopard roams a very small range in China and southeastern Russia, and it's vulnerable to all kinds of threats, such as poaching, illegal logging, and loss of habitat to humans, as well as disease and even inbreeding.

"We don’t know how many of the Amur leopards remaining in the wild are young or old, male or female," said Dr. John Lewis, veterinary advisor to the Amur leopard and tiger European Endangered Species Program (EEP) and veterinary director of Wildlife Vets International, in a press release.

"If the population is skewed towards too many males, or too many older individuals, this can impact the species’ chances of breeding successfully," Lewis said.

With breeding in the wild such a dicey prospect, the EEP's expert advisors keep a sharp eye on captive Amur leopard populations throughout Europe, ever on the lookout for suitable pairs that might breed.

The zoo is understandably thrilled with the births, as the cubs will help ensure the very survival of the species.

"We are hopeful that these UK-born babies will one day be part of wider conservation plans for the reintroduction of the species to the wild," Dr. Charlotte Macdonald, the zoo's head of life sciences, said in a release.

Macdonald, whose Twycross Zoo is a member of the EEP's captive-breeding initiative, says it will likely be several more years before any such reintroduction plans plans can be realized.