While conducting a photographic survey of the giraffe population in Uganda’s Murchison Falls National Park, a team of researchers noticed something unusual. One of the wild giraffes looks somewhat different from the others, having significantly shorter legs despite appearing as sub-adult body size. Then, while conducting similar work in Namibia, they discovered a second wild giraffe with an abnormality of similar size. The giraffe calf matures somewhere between three and six years of age and this second giraffe was thought to have been born in 2014, which means this person should show the length of an adult.
The researchers believe that both giraffes have been affected by conditions such as skeletal dysplasia (an umbrella term for conditions that affect the length of limbs, including dwarfism). Their paper in the journal BMC Research Notes describes the first giraffes with this condition found in the wild.
Before diving into why these animals evolved so differently from their fully grown giraffe friends, it’s best to first touch on how you’re going to measure giraffes. With an average height of 4.6 to .1.1 meters (15.1 to 20 feet), this is not an easy task for a relatively small person with a measuring tape. It is also important when conducting research on wildlife that this kind of data collection is not invasive as disrupting these animals can have negative consequences for their behavior or survival.
To overcome this, a method for measuring an elephant called photogrammetry was developed. The technique uses a laser rangefinder to measure the distance between features of interest. By determining the distance between the digital pixels in the photos and comparing them to the actual size of the focus feature, they can provide accurate measurements from photographs of large animals, including giraffes. By comparing these metaphorical data, the researchers were able to establish that the two giraffes that appeared abnormally brief were significantly different from the average height of each giraffe population. The Ugandan giraffe had a phalanx (lower part of the leg) that was the same length as its peers, but this part of the Namibian giraffe’s tail was significantly shortened, measuring 21.2 centimeters (8.3 inches) and 15.8 centimeters (meters 6.2 inches), respectively. Both animals had metacarpal and radial measurements compared to the average.
Interestingly, the Ugandan giraffe is made for a slightly smaller size with its cell length which is usually about 1.5 meters (4.9 feet) longer than the 1.4 (4.6 feet) presentation giraffe. Namibian giraffes were again below average in this category. The authors write that this kind of skeletal dysplasia has been reported for the first time in wild giraffes, and speaking to some members of the zoo community, it does not appear that it was observed in any captive animal. How common it is in nature, is hard to infer from photographic surveys because finding such animals is like finding a small fluffy needle in a stack of somewhat elongated flower needles. Researchers have not been able to find any members of the scientific and zoo community who have seen giraffes before, but it is understood that this is probably rare.
So why didn’t these two animals grow long legs that are characteristic of giraffes? “It’s hard to say specifically, but we speculate that skeletal dysplasias may be related to some genetic disorders, as the emergence of skeletal dysplasias is often involved in molecular etiologies,” said co-author Michael B. Brown, a conservation biologist at Giraffe Conservation Foundation, reported.
“It is noteworthy that as a result of civil unrest and poaching, the giraffe population in Uganda’s Murchison Falls National Park created a significant population barrier in the late 1980s. Since then, the population has returned significantly with the current estimate of about 1,500 giraffes, although it is not yet clear whether there has been any lasting impact on previous population disasters. “