Two giraffes that died during an intense storm in the Northern Cape are believed to have been killed by lightning.
A fracture at the junction of one of the animal’s horns and its skull suggested she was killed by a direct strike, according to a wildlife management expert who reported the deaths in the African Journal of Ecology.
The other giraffe, a female whose body was found seven metres away, had no signs of injury and is believed to have been killed by lightning that hit the ground near her, so-called step potential, or by “side flash” from a nearby object struck by lightning.
Ciska Scheijen, a 31-year-old Dutch scientist based at the 12,000ha reserve where the giraffes died, said she believed the fatalities were the kind of “fortuitous destruction” Charles Darwin said, in The Origin of Species, left natural selection “powerless”.
When the giraffes’ bodies were found two days after the storm, Scheijen said they smelt so strongly of ammonia that “I could not even stand close to them”.
It was notable that predators had avoided the corpses, she said, because it confirmed previous speculation linking the smell of ammonia to animals killed by lightning.
Speaking to Times Select from Rockwood, 180km east of Kimberley, Scheijen said she was in the midst of studying the behaviour and hormones of the reserve’s eight giraffes when a huge storm dumped 65mm of rain in two hours on February 29.
Accompanied by a howling gale, it destroyed many kilometres of new game fencing, erected to protect the reserve’s rhinos, and “left the whole farm looking like a river”.
The scene at Rockwood, in the Northern Cape, after a two-hour storm on February 29 2020 that dumped 65mm of rain, destroyed kilometres of game fencing and killed two female giraffes. @TimesSelect. Video supplied by Ciska Scheijer pic.twitter.com/kKwP1hGWhH
— David Chambers (@daveincapetown) September 17, 2020
Scheijen said: “We do get thunder, rain and storms, but nothing like this. We have rangers on motorcycles and horses, and we had to get them out because it was too dangerous.
“There was less than a second between the thunder and lightning, and I remember saying to one of the rangers: ‘This is definitely on the property’.”
Writing in the ecology journal, Scheijen said only six giraffes could be seen the next morning. This was “highly unusual” because members of the herd always grazed within a kilometre of each other.
The corpses were found the next day, with the only sign of injury the wound on the one animal’s head. “There were no large trees nearby and she was lying on her left side, indicating that she could not have broken her ossicone [horn] at the base during her fall to the ground,” said Scheijen.
“Given that lightning bolts tend to hit tall objects, especially in open areas, the height of giraffes may make them particularly vulnerable to fatal electrocution.”
The two deaths showed that fortuitous destruction was real, said Scheijen. “The towering height of giraffes poses a risk by acting like a lightning rod, so the adaptive advantages of a long neck can be overcome by chance events.”
Writing in Vulture News in 2014, University of Pretoria forensic pathologist Ryan Blumenthal described how lightning killed a giraffe on a game farm near Phalaborwa, Limpopo.
“The carcass initially showed blackening of the head and neck; no other external injuries to the body could be identified. An unusual ‘ammonia-like’ smell was present around the carcass,” he said, adding that “vultures and hyenas did not feed on the carcass for five days after the incident”.
Blumenthal wrote: “According to the owners of the farm, the smell from the giraffe carcass was overwhelmingly different from their usual experience when near decaying carcasses. Their dog reacted strangely and would not go close to investigate, which according to them was out of character.
“Some farmers in the nearby Klaserie region report that as many as 30 vultures will sometimes sit around a carcass for three days continuously without coming down to feed, and then flying away.”
He speculated that singed fur could release a sulphurous smell and that corpses could emit chemical and organic compounds.
About 40% of giraffes have vanished since the 1980s, reducing their population to about 68,000. Last year, they were given a listing by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (Cites) that restricts trade in their body parts.
