Giraffes are tough animals that can handle changes in food and pressure from humans. People usually think of them as living in flat, open grasslands in Africa, but their real home can also include hilly areas, deep riverbeds, and high plateaus.
A new study looked at the movements of 33 giraffes wearing GPS collars in South Africa. It found that giraffes have trouble with slopes steeper than 20°, so they prefer flat ground.
This is probably because it’s harder for them to move on steep slopes, and they risk falling. The research from the University of Manchester and the University of the Free State showed that giraffes can handle slopes up to 12° if it leads to good food.
Jessica Granweiler, a PhD candidate at the University of Manchester, said, “It’s quite shocking when you look at distribution maps. But this is a scenario where they may be unable to adapt due to physiological limits.”
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The study shows that giraffes’ natural preference for flat land doesn’t match the places where they are often protected. Using the 20° slope limit they discovered, the researchers figured out how much of the land in key African countries where giraffes live is too steep for them to reach.
The study used GPS data collected between 2011 and 2023 by Dr. Francois Deacon’s team at the University of the Free State in South Africa. They had fitted GPS collars on 33 giraffes (10 males and 23 females) across five reserves.
The researchers combined this data with topographic maps to determine which slopes giraffes could handle and which could not.
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Jessica said, “In Namibia and Tanzania, approximately 8,000 km2 may be unusable to giraffes that are nearly half the size of Wales. In Kenya and South Africa, approximately 4,000 km2 may be unusable. What’s even more worrying is that of all the countries we mapped, one in three had more unusable areas in protected areas than outside of protected areas.”
“This issue is exacerbated when reserves are fenced, as many in South Africa are. If a reserve is 200 hectares but has a large mountain in the middle, from a giraffe’s perspective, this reserve is not 200 hectares anymore. We must start including topography in giraffe conservation planning and habitat assessments, especially for small fenced reserves.”
Professor Susanne Shultz, lead supervisor on Jessica’s PHD, further commented: “Steep and rugged environments are challenging for large-bodied animals, like giraffes. Unfortunately, natural and protected areas are more likely to be placed in such places, which can lead to a mismatch between the landscapes animals’ want’ to use and the landscapes that we have ‘left’ for them. Incorporating geography and physical limitations in habitat assessments can help avoid conserving animals in inappropriate places.”
Dr Francois Deacon, who was also involved in this research, said, “The more awareness we can bring to giraffe ecology, the more research effort there will be on this species in the future. The fact that we are still discovering major limitations or drivers of their ecology and behavior is worrying. But research like ours helps close this gap in knowledge and will help better manage and conserve giraffes in the future.”
The findings will be presented at the British Ecological Society’s (BES) Annual meeting in Liverpool on December 13th.