Animals Wildlife 11 Things You Might Not Know About Giraffes These gentle giants evolved long necks to reach nutritious tree leaves. By Russell McLendon Senior Writer University of Georgia Russell McLendon is a science journalist who covers a wide range of topics about the natural environment, humans, and other wildlife. our editorial process Russell McLendon Updated September 17, 2020 A group of giraffes, known as a 'tower,' stare down a photographer in Tanzania's Mkomazi National Park. Soaring Flamingo / Flickr / CC BY-ND 2.0 Share Twitter Pinterest Email Animals Wildlife Pets Animal Rights Endangered Species Giraffes are the tallest land animals alive today, with adult giraffes standing up to 20 feet (6 meters) tall. While their remarkable height is common knowledge, many people know little else about these gentle giants. Despite their impressive stature, giraffes keep a relatively low profile, often quietly munching leaves in the background while other animals hog the spotlight. Even scientists and conservationists have a history of overlooking giraffes, at least compared with some other species (although, fortunately, that has begun to change in recent years). These fascinating megafauna are increasingly threatened animals who need our help to avoid fading away in the wild. 1. The First Giraffes May Have Evolved in Europe Although giraffes now live only in sub-Saharan Africa, research suggests the ancestors of modern giraffes probably evolved in southern central Europe about 8 million years ago. They entered Africa through Ethiopia about 7 million years ago, according to a study published in the Transactions of the Royal Society of South Africa, finding more success there than relatives who moved to Asia and died out a few million years later. Giraffe evolution seems to have been driven mainly by shifts in vegetation, the researchers reported, from forest to a mix of savanna, woodland, and shrubs. The giraffes' tallest ancestors would have had an advantage in reaching nutritious tree leaves in this habitat, so taller individuals were likelier to pass on their genes. This evolutionary process resulted in giants who could feast on foliage well beyond the reach of other animals. In addition, males fight with their long necks, adding even more selective pressure. Safety from predators is a big perk, too – their height means giraffes can see danger from far away, and they aren't easy for predators to subdue. 2. There Are Several Species in the Giraffe Family (Including One Non-Giraffe) The okapi is considered the closest living relative of giraffes. Daniel Jolivet / Flickr/ CC BY 2.0 Giraffes were long seen as one species with nine subspecies. That's still how the International Union for Conservation of Nature (IUCN) classifies them, but not everyone agrees. A 2001 study suggested two species exist, followed by another in 2007 that identified six species. Other studies have gone as high as eight, but many scientists now recognize three or four giraffe species. In the four-species taxonomy, there is the northern giraffe (Giraffa camelopardalis), southern giraffe (G. giraffa), reticulated giraffe (G. reticulata), and Masai giraffe (G. tippelskirchi). The northern giraffe has three subspecies (the Kordofan, Nubian, and West African giraffes), and the southern giraffe has two (the Angolan and South African giraffes). This classification is embraced by the Giraffe Conservation Foundation (GCF), which notes it is based on genetic analysis of more than 1,000 DNA samples taken from all major giraffe populations across Africa. These giraffes are the only living members of the genus Giraffa, but if you zoom out one taxonomic level to the family Giraffidae, they are joined by another genus. It includes just one species, the okapi, a forest dweller whose slightly elongated neck hints at its relation. Research indicates the last common ancestor of giraffes and okapis lived about 11.5 million years ago. 3. Giraffes Hum to Each Other at Night Aside from subtle grunts and snorts, it was long believed giraffes don't vocalize. With such long necks, many scientists reasoned, it would be too difficult for giraffes to generate enough airflow to make audible sounds. However, in a 2015 study, a team of biologists reported evidence of giraffes at three zoos humming to each other at night. Much is still unknown about these hums, which the researchers describe as "rich in harmonic structure, having a deep and sustained sound." It's unclear if they are truly a form of communication, but the study's authors speculated they may serve as contact calls to help the animals stay in touch after dark. 4. Even Newborn Giraffes Are Taller Than Most People A mother giraffe grooms her calf in Tanzania's Serengeti National Park. Alberto Cassani / Getty Images Newborn giraffes are roughly 6 feet (1.8 meters) tall and 220 pounds (100kg). The mother giraffe, whose legs alone are about 6 feet long, gives birth standing up, so the calf must endure a long drop to the ground. Yet it still stands up on its spindly legs within about an hour of birth. That quick adjustment is important. While adult giraffes are tall and massive enough to fend off most predators, the same isn't true for their calves, about half of whom don't survive their first year. 5. You Have the Same Number of Neck Vertebrae as a Giraffe Adult giraffes are two times as tall as the rim of a basketball goal. With so much of that height found in their necks, it would be sensible to assume they have more neck vertebrae than we do – but it would be wrong. Giraffes, humans, and nearly all other mammals have seven cervical vertebrae. As you might imagine, giraffes' vertebrae are not exactly like ours. A single vertebra in a giraffe's neck can measure 11 inches (28 cm) in length, which is longer than the entire neck of most humans. 6. Giraffes Have Long, Prehensile Tongues Giraffes have incredibly long, prehensile tongues to help them rip leaves from trees. Buena Vista Images / Getty Images The diet of a giraffe consists mainly of fresh leaves and twigs from treetops, especially acacia. In addition to the obvious boost they get from their long legs and necks, their tongues play a key role in helping them access this exclusive food source. Giraffes' bluish-purple tongues are about 18 inches (45 cm) long. They're also prehensile, helping giraffes wrap them around leaves and deftly pull them from between the thorns found on acacia trees. Giraffes eat up to 66 pounds (30 kg) of food per day, and the dark color of their tongues may help them eat all day without suffering sunburns. 7. They Don't Drink Much Water An Angolan giraffe bends down for a drink of water. Dorit Bar-Zakay / Getty Images The giraffe's long neck isn't quite long enough to enable it to drink water while standing upright. To get its mouth down to a water source, a giraffe must either kneel or awkwardly splay out its front legs. Giraffes only drink water once every few days; even when water is readily available, they rarely drink it, according to the Giraffe Conservation Foundation. Instead, giraffes get most of their water from the plants they eat. They may be more resistant to drought than some other animals. The tall trees on which they feed tend to have deeper roots, enabling the trees to tab into water deep underground that isn't available to shorter trees — or the shorter animals that feed on them. 8. They Have High Blood Pressure Long necks have given giraffes a key evolutionary advantage, but they also make it more difficult to pump blood up to the brain. Anup Shah / Getty Images Since giraffes' heads are located so far from their hearts, their bodies face a unique challenge in pumping blood up to the brain. As a result, giraffes have evolved extremely high blood pressure of 280/180 mm Hg, which is roughly twice that of humans, according to the GCF. A giraffe's heart typically beats 40 to 90 times per minute when resting, but it may surge up to 170 beats per minute when the animal is running. A giraffe's heart can weigh up to 24 pounds (11 kg) – reportedly the largest heart of any land mammal, although not quite as large as once believed, the GCF explains. The heart reportedly relies on unusually thick walls of the left ventricle to generate such high blood pressure, pumping up to 15 gallons (60 liters) of blood through the body every minute. 9. They Might Be Able to Swim The body shape of giraffes does not lend itself to moving through water, and it was long believed that giraffes simply can't swim. According to a 2010 study, however, giraffes probably are capable of swimming, even if not very gracefully. Rather than testing this with actual giraffes, the researchers used computational analysis to examine how the mechanics of a swimming giraffe might work. They found that a full-sized adult giraffe will become buoyant in water deeper than 9.1 feet (2.8 meters), at which point it might be able to swim if it really needed to. "While it is not impossible for giraffes to swim, we speculate that they would perform poorly compared to other mammals and are hence likely to avoid swimming if possible," the researchers wrote. 10. Their Coat Patterns Are Unique, Like Our Fingerprints Some giraffe species (or subspecies) have distinctive types of spots, but the exact pattern is different for every individual. Charlie Marshall / Flickr / CC BY 2.0 All giraffes have spotted coats, but no two giraffes have the same pattern. Some researchers can even recognize individual giraffes by their distinctive patterns. These spots may have evolved at least partly for camouflage, which could be especially valuable for youngsters who are still short enough to be vulnerable to predators. The spots might also help dissipate heat around a giraffe's body, since the skin temperature is slightly higher on the darker regions, and could play a role in social communication. 11. They May Be Suffering a Silent Extinction A giraffe walks toward the sunset in Kenya's Maasai Mara National Reserve. Marcel Oosterwijk / Flickr / CC BY-SA 2.0 About 150,000 wild giraffes existed as recently as 1985, but there are now fewer than 97,000, according to the IUCN. In 2016, the IUCN moved giraffes from "Least Concern" to "Vulnerable" on its Red List of Threatened Species. The IUCN still classifies all giraffes as one species, but in 2018 issued new listings for seven of the nine subspecies, listing three as "Critically Endangered" or "Endangered" and two as "Vulnerable." Giraffes are already extinct in at least seven countries, according to the GCF, and now their remaining population has shrunk by about 40% in 30 years. Their decline is largely attributed to habitat loss and fragmentation, along with threats from poaching and droughts, which are becoming more severe due to climate change. The plight of giraffes has received relatively little public attention and scientific study compared with other iconic African animals like elephants and rhinos, leading some conservationists to warn a "silent extinction" could be underway. There have been some hints of hope in recent years, however, including more publicity of their decline and population gains among certain subspecies.