Giraffes are the tallest mammals on earth—and their height isn’t just about bragging rights in the animal kingdom. Being tall, on average 16-20 feet, gives them the pick of the best foliage in the jungle, an evolutionary advantage that’s widely accepted in the scientific world. Which is why researchers from the Giraffe Conservation Foundation were surprised to find two dwarf giraffes—one in Uganda’s Murchison Falls National Park and another three years later on a private farm in Namibia.
The team studied the animals from 2014 to 2019 and published their findings in the British Medical Journal last month. Both giraffes had long necks but shorter legs. The scientists measured, observed and studied the animals over a few years, and found that “both giraffe with abnormalities had skeletal proportions that differed significantly from population level measurements of subadults,” according to the research paper.
“It’s fascinating what our researchers out in the field found,” Julian Fennessy, co-founder of the Giraffe Conservation Foundation (GCF), told Reuters. “We were very surprised.” The dwarf giraffe still stands head and shoulders above the average human at about 9 feet (2.8 metres).
The GCF team concluded that the giraffes had a condition known as skeletal dysplasia, which affects bone development and growth, and often results in short stature. So far, it had been observed and studied in humans and domesticated animals like dogs and cows, but it’s rare in wild animals, and this first time it has been observed in giraffes. The few known examples of this condition in wild animals include a male Asian elephant in Sri Lanka and one red deer in Scotland. “These developmental aberrations are sometimes characterized by shortened and irregularly proportioned appendicular skeletal anatomy, resulting in what is vernacularly described as disproportionate dwarfism,” GCF’s Michael Butler Brown and Emma Wells write. The researchers came across the animals during their regular population surveys.
Although rarely observed in wild animals, there have been cases of skeletal dysplasia in captive animals, and it has usually been associated with inbreeding and a lack of genetic diversity. Whether this caused the dwarfism in the animals is unclear, but across Africa, giraffes are categorised as ‘vulnerable’. Over the past three decades, their numbers have declined about 40% due to habitat loss and fragmentation, changing land use patterns and poaching.
“Unfortunately there’s probably no benefit at all. Giraffes have grown taller to reach the taller trees,” Fennessy said. He added that it would most likely be physically impossible for them to breed with their normal-sized counterparts. In fact, the limited mobility caused by having shorter legs might make these giraffes more susceptible to predation.