by Greg Mayer

The five living species of rhino, along with the several species of tapir and horse (which include the zebras and asses), are members of the great mammalian order of odd-toed ungulates, or Perissodactyla. Perissodactyls were formerly much more species rich; today, most ungulates (hoofed mammals) are even-toed, members of the Artiodactyla, which includes cattle, deer, antelope, sheep, goats, pigs, etc.– the dominant large land herbivores of our world. Of those perissodactyls still with us, the rhinos have suffered the most at the hand of man, and all five species have been or are critically endangered.

The most endangered of rhinos is the northern white rhino (Ceratotherium simum cottoni) of central Africa, a subspecies of the white rhino, and its condition became extremely precarious last Sunday when the San Diego Zoo’s male northern white rhino, Angalifu, died at the age of 44 from old-age related ailments. There is now only one male northern white rhino left alive, along with 4 females (singleton females at San Diego and in the Czech Republic, all the rest, including the male, in Kenya).

Rhino horns are prized for their use in Eastern “medicine”, and their value has led to remorseless hunting that has driven many species nearly to extinction.

When I first began following such things about 1970, the other African rhino, the black rhinoceros, Diceros bicornis, was in relatively good shape, while the white rhino, both the northern subspecies in central Africa, and the southern subspecies (C. s. simum) in southern Africa, was critically endangered.

The news since then has been good, bad, and bad. The good news first. Thanks to strong conservation efforts, including captive/ranch breeding, the southern white rhino has bounced back, and there are over 20,000 of them now. The first bad news is that black rhinos have declined tremendously: although up a bit lately, they are down to about 5,000, a loss of over 90% since 1970. And the worst news of all is that the northern white rhino has declined to now just 5. In addition to the death of Angalifu, another male died earlier this fall. It seems to me that the only way to preserve any living representation of the northern subspecies at all now would be through crossing with the southern subspecies. Although captive/ranch breeding has not worked well for northern whites, it has for southern whites. I would assume that blood and tissue sample have been taken to assure that the genomic information at least could be saved, even if the living species cannot be. The loss would be compounded by the fact that some consider the northern white to be a separate species, so that its extinction would not merely be the loss of a local population, but of a more genetically distinct form.

Further info on rhinos can be found at the International Rhino Foundation and Save the Rhino, two conservation organizations, and at the Rhino Resource Center, a wonderful site which contains a wealth of information, including a huge database of the primary literature on rhinoceroses (many with full text) and many rhino images. The site was created by Kees Rookmaaker, an historian of biology, who is also one of the chief contributors to Darwin and Wallace Online, two of our favorite websites, edited by our old friend John van Wyhe.

In the following video, made by the San Diego Zoo earlier this fall, one of their curators discusses the causes of the rhinos endangerment. Ironically, he is expressing hope that the San Diego pair might breed, in light of the death of one of the two males in Kenya.

* News reports have been inconsistent in their identification of which of the San Diego Zoo’s two northern white rhinos, Anaglaifu the male and Nola the female, are depicted in photos and videos. Identification of the individual(s) in pictures has been hampered by the fact that rhinos can be easily sexed only when seen from behind, and that the Zoo has trimmed their horns on various occasions. I believe the animal in the photo at top is Angalifu, while the animal with the concave-downward horn featured in most of the video is Nola. The San Diego Zoo surely knows, but they have not published side by side photos.