With an average height of approximately 16 feet, giraffes are the tallest mammals on earth. About six feet long, their lanky legs and soaring necks are taller than most people. Even the shortest giraffe is twice the size of the average professional basketball player.
When Michael Brown, a naturalist with the Giraffe Conservation Foundation and the Smithsonian Conservation Biology Institute, and colleagues came across a Nubian giraffe that was only 9 feet tall in 2015 in Murchison Falls National Park, Uganda, they did a double take.
“The first reaction was disbelief,” said Dr. Brown.
The giraffe’s neck – nicknamed Gimli – was characteristically long, but its legs were not. It looked like someone had placed the head and neck of a giraffe on the body of a horse.
Then, just three years later, an 8-1 / 2-foot Angolan giraffe nicknamed Nigel was found on a private farm in central Namibia. After measuring and analyzing the dimensions of the two giraffes, the researchers could only find one explanation: dwarfism.
The condition, also known as skeletal dysplasia, affects bone growth and often leads to short stature. Although it is known to occur in humans and pets such as dogs, cows, and pigs, dwarfism is rarely seen in wildlife, and this is the first time it has been found in giraffes.
The discovery, announced in an article published last month in BMC Research Notes magazine, provides scientists with a unique opportunity to study the effects of dwarfism on wild animals.
When photos of the dwarves began circulating online, many people assumed the images had been tampered with.
“I didn’t believe it at first,” said David O’Connor, President of Save Giraffes Now and a member of the IUCN Giraffe and Okapi Specialist Group. “I thought it was Photoshopping to be honest.”
The researchers who discovered Gimli and Nigel photographed the creatures extensively and used digital photogrammetry techniques to measure the length of their limbs. After comparing the dimensions of the dwarf giraffes, both mature males, with those of similar ages from the same population, they found that the dwarfs had much shorter legs; In particular, they had a much shorter radius and metacarpal bones.
More than half of wild giraffes die before they reach adulthood. The fact that both Gimli and Nigel outperformed the odds suggests that their dwarfism didn’t affect their survivability. However, their size or absence almost certainly complicates many aspects of their life.
“It is easy to see how this could make them more vulnerable to predators since they are unable to run and kick effectively. These are two of the giraffe’s most effective anti-predator tactics,” said Dr. Brown. “Also, given the mechanics of mating giraffes, I would speculate that mating would be a physical challenge for both giraffes.”
Although female giraffes tend to be shorter than males, it would be nearly impossible for an 8- or 9-foot male to climb even the shortest woman, “unless they are given a step stool,” said Dr. O’Connor.
The cause of this dwarfism remains a mystery. Although random mutations can lead to this disorder, dwarfism in captive animals has been linked to inbreeding and lack of genetic diversity. Whether these factors influenced the dwarfism of Gimli and Nigel remains unclear.
The giraffe population, which also includes Gimli, saw a significant decline in the late 1980s, bringing the total to just 78 at one point. It now consists of more than 1,500 people. More research is needed to determine whether a lack of genetic diversity caused Gimli’s condition.
Although scientists know very little about giraffes compared to other cult animals, they do know that the towering mammals are in trouble. Habitat loss and poaching have reduced their numbers by an estimated 40 percent over the past 30 years, and some subspecies, including the Nubian giraffe, are now critically endangered. To counteract this decline, Dr. Brown and other scientists studied and monitored as many wild giraffe populations as possible.
“Population surveys are a critical part of our mission to develop effective protection strategies based on solid scientific evidence,” said Dr. Brown.
Nigel was discovered during a survey conducted by the foundation in July 2020, but Gimli has not been seen since March 2017. The researchers hope that both giraffes will reappear soon.
By monitoring throughout their lives, the scientists hope to “get some interesting stories and nice little wrinkles about how animals in such conditions deal with changing environments,” said Dr. Brown.
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