Phalaborwa, in South Africa's Limpopo province, is an ex-copper mining town surrounded by game farms and lodges, game sanctuaries and nature reserves. Bordering on the Kruger National Park, the town's residents have plenty of opportunity for animal-watching. It was during one of the frequent thunder storms that Ralph Volker began noticing something unusual in one of the nearby game farms.
"Most of the animals on this farm seem to have learnt that when a thunderstorm breaks, the safest place to avoid being struck by lightning is in the valleys: certainly not on the hills and mountains," he says. "So when the storm starts they all congregate in these valleys. Unfortunately for the poor giraffes, their long necks disadvantage them over the buck and other shorter animals, so not only do they get down into the valleys during a thunderstorm but they hunker down to try to be the shortest."
Giraffes Killed by Lightning
That giraffes should be wary of lightning is well documented. Famous unfortunates include the 12-foot Betsy, killed during a storm at Walt Disney World in Florida. Closer to home, the South African Times reported that in 1996 lightning struck and killed a giraffe standing on a hill in the Rhino and Lion Reserve of Kromdraai. A year later lightning electrocuted his mate. Soon after that, lightning struck and injured a young giraffe in the park leading the reserve to sell its giraffe's and refuse offers of more.
Wild giraffes range across the dry savannah and semi-desert south of Africa's Sahara and tend to lose out in height to the trees. In the game reserves where many now find themselves however, they're dangerously tall. "If there's a lightning leader already approaching the ground, it will certainly look for something tall to hit in its immediate vicinity," says Professor David Smith of the University of California's physics department. "Since water is pretty conductive (particularly salty water), your giraffe is a pretty good conductor and probably does attract lightning pretty well.
Potential Drop Dangerous
"But even if it hit a nearby tree or something, he would still be in trouble. When the leader connects with the ground, current rushes quickly through the ground from the surrounding area and up through the lightning channel. Let's say the giraffe's feet are placed ten feet apart. Since a giraffe is more conductive than the ground, the current will take a little detour up one leg, across the giraffe, and down the other, rather than continuing to travel through the ground. This can be fatal. The wider the animal's stance, the greater the potential drop (voltage) between one foot and the other, and the more energy the current will deposit."
This potential difference was responsible for the death of Dusty, a one-year-old giraffe in Louisiana's Global Wildlife Center who happened to be standing next to a tree which was struck by lightning. It would therefore follow that giraffes huddling together in storms would do more harm than good, increasing as it does the potential drop. "Someone should tell the giraffes," suggests Professor Smith.
According to Jon Richfield, writing in the New Scientist (24th October 1998), "Even in the Bushveld, a low-lying area where thunderstorms are common, lightning is not a leading cause of giraffe death. There seems to have been no evolutionary selection for specific avoidance behaviour." Dr Anne Dagg, a spcialist in giraffe's behaviour, is also doubtful that giraffes would attempt to make themselves shorter in the herd. "It is hard to visualize how such behaviour would have arisen in giraffe," she says. "I haven't heard anything like this at all before."
Justin Schamotta - Justin was born in South Africa, raised in the Welsh Valleys and now resides in Brighton. He has been co-editor of Bulb magazine, deputy ...
