Both black and white rhinos are actually shades of gray; the difference betwen them has to do with diet, not skin color. White rhinos are grazers, their heads almost always down on the ground, their wide, straight mouths constantly mowing the grass. They are sometimes known as square-lipped rhinos. Black rhinos, by contrast, are browsers. They snap off low acacia branches with the chisel-like cusps of their cheek teeth and swallow them thorns and all. “Here,” Bird said, indicating a scissored-off plant. “Sometimes you’re walking and if you’re quiet, you can hear them browsing 200 or 300 meters ahead. Whoosh, whoosh.” Blacks, also known as hook-lipped rhinos, have a powerful prehensile upper lip for stripping foliage from bushes and small tree branches. The lip dips down sharply in the middle, as if the rhino had set out to grow an elephant trunk but ended up becoming Dr. Seuss’ Grinch instead.
We followed the bent grass the rhinos had trampled, crossed through a deep ravine and came out onto a clearing. The white rhinos were moving off, with tick-eating birds called oxpeckers riding on their necks. But the black rhinos had settled down for a rest. “We’ll go into those trees there, then wake them up and get them to come to us,” Bird said. My eyes widened. We headed out in the open, with nothing between the rhinos and us except a few hundred yards of low grass. Then the oxpeckers gave out their alarm call—“Chee-cheee!”—and one of the black rhinos stood up and seemed to stare straight at us. “She’s very inquisitive,” Bird said. “I train a lot of field rangers, and at this point they’re panicking, saying, ‘It’s got to see us,’ and I say, ‘Relax, it can’t see us.’ You just have to watch its ears.”
The rhino settled down and we made it to a tree with lots of knobs for hand- and foot-holds where elephants had broken off branches. Bird leaned his rifle against another tree and we climbed up. Then he started blowing out his cheeks and flapping his lips in the direction of the rhinos. When he switched to a soft high-pitched cry, like a lost child, a horn tip and two ears rose above the seed heads of the grass and swung in our direction like a periscope. The rest of the rhino soon followed, lifting up ponderously from the mud. As the first animal ambled over, Bird identified it from the pattern of notches on her ears as C450, a pregnant female. Her flanks were more blue than gray, glistening with patches of dark mud. She stopped when she was about eight feet from our perch, eyeing us sideways, curious but also skittish. Her nostrils quivered and the folds of flesh above them seemed to arch like eyebrows, inquiringly. Then suddenly her head pitched up as she caught our alien scent. She turned and ran off, huffing like a steam engine.
A few minutes later, two other black rhinos, a mother-daughter pair, came over to investigate. They nosed into our small stand of trees. Bird hadn’t figured they would come so close, but now he worried that one of them might bump into his rifle. It would have been poetic justice: Rhino shoots humans. He spared us by dropping his hat down in front of the mother to send her on her way.
Rhino pregnancies last 16 months, and a mother may tend her calf for up to four years after birth. Even so, conservation programs in recent decades have managed to produce a steady surplus of white rhinos. Conservationists hope to increase the black rhino population as a buffer against further poaching, and their model is what Hluhluwe-iMfolozi did for white rhinos beginning in the 1950s.
South Africa was then turning itself into the world leader in game capture, the tricky business of catching, transporting and releasing big, dangerous animals. White rhinos were the ultimate test—three tons of anger in a box. As the remnant Hluhluwe-iMfolozi population recovered, it became the seed stock for repopulating the species in Botswana, Zimbabwe, Mozambique and other countries. In South Africa itself, private landowners also played a key part in rhino recovery, on game farms geared either to tourism or trophy hunting. As a result there are now more than 20,000 white rhinos in the wild, and the species is no longer on the threatened list.
Building up the black rhino population today is more challenging, in part, because human populations have boomed, rapidly eating up open space. Ideas about what the animals need have also changed. Not too long ago, said Jacques Flamand of the World Wildlife Fund, conservationists thought an area of about 23 square miles—the size of Manhattan—would be enough for a founding population of a half-dozen black rhinos. But recent research says it takes 20 founders to be genetically viable, and they need about 77 square miles of land. Many rural landowners in South Africa want black rhinos for their game farms and safari lodges. But few of them control that much land, and black rhinos are far more expensive than whites, selling at wildlife auctions for about $70,000 apiece before the practice was suspended.
So Flamand has been working with KwaZulu-Natal (KZN) Wildlife, the provincial park service, to cajole landowners into a novel partnership: If they agree to open up their land and meet stringent security requirements, KZN will introduce a founding population of black rhinos and split ownership of the offspring. In one case, 19 neighbors pulled down the fences dividing their properties and built a perimeter fence to thwart poachers. “Security has to be good,” said Flamand. “We need to know if the field rangers are competent, how they are equipped, how organized, how distributed, whether they are properly trained.” Over the past six years, the range for black rhinos in KwaZulu-Natal has increased by a third, all on private or community-owned land, he said, allowing the addition of 98 animals in six new populations.
Conservationists have had to think more carefully about which animals to move, and how to move them. In the past, parks sometimes transferred surplus males without bothering to include potential mates, and many died. But moving mother-calf pairs was perilous, too; more than half the calves died, according to Wayne Linklater, a wildlife biologist at New Zealand’s Victoria University and lead author of a new study on black rhino translocations. Catching pregnant females also created problems. The distress caused by capture led to some miscarriages, and the emphasis on moving numerous young females may also have depleted the literal motherlode—the breeding population protected within Hluhluwe-iMfolozi. “We were left with a whole lot of grannies in the population, and not enough breeding females,” said park ecologist David Druce.
Researchers have now come to recognize that understanding the social nature of black rhinos is the key to getting them established, and reproducing, in new habitats. A territorial bull will tolerate a number of females and some adolescent males in his neighborhood. So translocations now typically start with one bull per water source, with females and younger males released nearby. To keep territorial bulls separated during the crucial settling process, researchers have experimented with distributing rhino scent strategically around the new habitat, creating “virtual neighbors.” Using a bull’s own dung didn’t work. (They are at least bright enough, one researcher suggests, to think: “That’s my dung. But I’ve never been here before.”) It may be possible to use dung from other rhinos to mark a habitat as suitable and also convey that wandering into neighboring territories could be risky.