A year later, in late 2007, I return to Niger and go into the bush with Jean-Patrick Suraud, a doctoral student from the University of Lyon and an ASGN adviser, to observe another census. It takes us only half an hour to find a cluster of seven giraffes. Suraud points out a male that is closely following a female. The giraffe nuzzles her genitals, which prompts her to urinate. He bends his long neck and catches some urine on his muzzle, then raises his head and twists his long black tongue, baring his teeth. Male giraffes, like snakes, elephants and some other animals, have a sensory organ in their mouth, called Jacobson's organ, that enables them to tell if a female is fertile from the taste of her urine. "It's very practical," Suraud says with a laugh. "You don't have to take her out to dinner, you don't have to buy her flowers."
Although the female pauses to let the male test her, she walks away. He does not follow. Presumably she is not fertile. He meanders off to browse.
If a female is fertile, the male will try to mount her. The female may keep walking, causing the male's forelegs to fall awkwardly back to the ground. In the only successful coupling Suraud has witnessed, a male pursued a female—walking alongside her, rubbing her neck, swaying his long body to get her attention—for more than three hours before she finally accepted him. The act itself was over in less than ten seconds.
Suraud is the only scientist known to have witnessed a peralta giraffe give birth. In 2005, after just six months in the field, he was stunned when he came upon a female giraffe with two hoofs sticking out of her vagina. "The giraffe gave birth standing up," he recalls. "The calf fell [six feet] to the ground and rolled a bit." Suraud smacks the top of the truck to illustrate the force of the landing. "I'd read about it before, but still, the fall was brutal. I remember thinking, ‘Ouch, that's a crazy way to come into the world.'" The fall, he goes on, "cuts the umbilical cord in one swift motion." Suraud then watched the mother lick the calf and eat part of the placenta. Less than an hour later, the calf had nursed and the two were on the move.
Though mother and calf stay together, groups of giraffes are constantly forming and re-forming in a process scientists call fission-fusion, similar to chimpanzee grouping. It is as common for half a dozen males to forage together as it is for three females and a male. In the rainy season, when food is plentiful, you might find a herd of 20 or more giraffes.
Unlike with chimps, however, it is almost impossible to identify an alpha male among giraffes. Still, Suraud says he has seen male giraffes mount other males in mock copulation, often after a fight. He's not sure what to make of the behavior but suggests it may be a type of dominance display, though there doesn't seem to be an overarching power hierarchy.
Competition among males—which grow to 18 feet tall and weigh as much as 3,000 pounds—for access to females, which are slightly smaller, can be fierce. Males sometimes slam each other with their necks. Seen from afar, a fight might look balletic, but the blows can be brutal. Idé says he witnessed a fight several years ago in which the vanquished giraffe bled to death.
As it happens, the evolution of the animal's neck is a matter of some debate. Charles Darwin wrote in The Origin of Species that the giraffe is "beautifully adapted for browsing on the higher branches of trees." But some biologists suggest that the emergence of the distinctive trait was driven more by sexual success: males with longer necks won more battles, mated more often and passed on the advantage to future generations.
Still, wild giraffes need a lot of trees. They live up to 25 years and eat from 75 to 165 pounds of leaves per day. During the dry season, Niger's giraffes get most of their water from leaves and the morning dew. They're a bit like camels. "If water is available, they drink and drink and drink," says Suraud. "But, in fact, they seem not to have a need for it."
Dovi points out places in the savanna where villagers have cut down trees. "The problem is not that they take wood for their own use; there's enough for that," he says. "The problem is that they cut down trees to sell to the market in Niamey."