One of only six remaining northern white rhino died Sunday, December 14th. Angalifu, the northern white rhino seen and photographed by millions of visitors over the last few decades, was 44 when he died of old age (natural causes) on Sunday at the San Diego Zoo Safari Park, Calif.

Only Five Northern White Rhinos Now Left In The World

Five northern white rhinos remain

After the death of Angalifu, the San Diego Zoo has just one northern white rhino left, an elderly female named Nola. Unfortunately, Angalifu and Nola were never able to successfully breed.

In addition to Nola, the only remaining northern white rhinos are:

Sudan, a male who lives in the Ol Pejeta Conservancy in Kenya;

Najin and Fatu, two females living in the Kenya preserve with Sudan;

And an unnamed elderly female at the Dvur Kralove Zoo in the Czech Republic. This zoo has control over  Sudan, Najin and Fatu, and sent them to Kenya several years ago to participate in a breeding program.

Probably too late for natural reproduction

Experts say the northern white rhino probably lost its last chance for natural reproduction when a male called Suni — the first ever born in captivity — died of unknown causes in Kenya this fall. Suni was part of the breeding program involving Sudan, Najin, and Fatu. When he died, the zoo announced Suni was “probably the last male capable of breeding.”

The Ol Pejeta Conservancy admitted for the first time that its breeding experiment had more or less failed. This means the final for the northern white rhino species is in “artificial reproductive techniques”. In this regard, the San Diego Zoo has stored some of Angalifu’s testicular tissue and sperm to be used to artificially breed new northern white rhinos in the future.

Southern white rhino

The southern white rhino is a distinct subspecies from the northern white, and has come back from the brink of extinction in the early 20th century.

After worries the species was already extinct, naturalists discovered a small population in southern Africa in 1895.  More than a century of intensive conservation efforts have followed, and experts estimate there are now around 20,000 southern white rhinos worldwide. That said, poaching is still a major threat, and the population is considered “near threatened” by major conservation organizations.