Expert: Jonathan Wright - 7/18/2005

Question
what noise does a giraffe make and why do they have little horns?

Answer
Dear Tricis

Thanks for your questions.

I have various sites above to give information about giraffe sounds, as well as the following websites: http://www.mybonbon.com/rainforest_sounds.htm http://www.wellingtonzoo.com/animals/animals/mammals/giraffe.html, http://ask.yahoo.com/ask/20030113.html http://www.havasu.k12.az.us/starline/akeller/elyssa.htm    
As giraffes are rarely heard, many people think they are mute. They are generally quiet, but will vocalize by emitting moans, hisses, snores, hisses, coughs, grunts, moos, snorts, bleats (similar to that of a young calf or sheep), low notes, low, fluttering sounds or flute-like sounds or whistles. They may make loud grunts, roars or snort when they feel alarmed or threatened. Courting males may let out a loud cough. Females may whistle to call their young or bellow when seeking lost calves. Calves can bleat and make mewing calls. Giraffes also produce infrasounds. Most of the time, the only noise made by giraffes is the gentle clicking of their hooves as they lift their feet clear of the ground.
http://www.pbs.org/wnet/nature/tallblondes/infrasound.html goes into detail about giraffe infrasound. These low-pitched sounds can travel farther than higher-pitched noises through the air and earth. Long-distance communication helps giraffes, which can be spread over vast territories. In 1998, Elizabeth von Muggenthaler of the Fauna Communications Research Institute in North Carolina and a group of colleagues announced that giraffes probably use infrasound to communicate, as she had studied the use of infrasound by the okapi. The researchers thought that giraffes probably used sounds, because they are very social, hide in forests (where visual communication is difficult) and hide their young while foraging. They are hunted by predators, but were thought to be mute. The researchers said that no other animals with similar behaviours were mute, as they would be unable to survive if they couldn't communicate. Also, the nature of the giraffes' ears show that thye can tune in on sounds.
In their zoo study, the researchers noticed that low sounds seemed to coincide with two behaviours: the "neck stretch," where giraffes throw their head and necks back over their bodies; and the "head throw," in which the animals lower and then quickly raise their chins.

http://www.nature-wildlife.com/girextra.htm http://www.sandiegozoo.org/animalbytes/t-giraffe.html, http://www.uoguelph.ca/~mammals/Prelab6.htm http://animaldiversity.ummz.umich.edu/site/topics/mammal_anatomy/horns_and_antlers.html, http://www.oaklandzoo.org/atoz/azgiraf.html and
http://www.geocities.com/mrp141/ give information about the horns of giraffes. Males and females have two paired, unbranched, bony processes, covered with skin and tufts of hair. These ‘horns' are called ossicones. They are neither true horns nor antlers. They differ from other horns of artiodactyls (even-toed hoofed mammals), as they do not project from the frontal bones of the skull. Instead, they lie over the sutures between the frontal and parietal bones. They also differ from true horns, as they are not epiphysial, but have their own centres of ossification (the process of forming bone). Ossicones are made of bone and are part of the skull. The horns are usually short, but may grow to about 30 cm long and are covered with skin and fur. The horns show a metabolic organization but with an influence of the nerve-sense system. The horns may represent relics of pedicles from which the antlers of grew millions of years ago; giraffes are fairly closely related to deer). Giraffe "horns" differ from antlers, because they are permanent and are not shed annually. Also, the overlying integument is never sloughed, while deer shed the velvet covering the developing antlers. Some extinct forms of giraffes, such as sivatheres, had ‘horns', which were similar to antlers.

Females have thick, hair-covered horns. Males have thicker horns that are bald on the top, as the upper ends are exposed due to fighting. The horns are surrounded with a tuft of hair and are used when fighting playfully with one another. They have parietal horns at the back of the head to fight with one another. Older giraffes are more dangerous in combat. As males age, calcium deposits form on their skulls, so that new horn-like bumps develop. Giraffes can have up to three of these large bumps, with two in the rear of the skull and one in the forehead region, so that they have five horns. The central swelling, between the eyes, may be almost as long as the horns in northern giraffes. The extra bone deposits on the skull may be used for fighting.

The giraffe is one of the few animals born with horns. In fact, the horns occur as pegs before birth and are unattached to the skull, but fold back during birth, when they lay on the skull. They are small knobs of cartilage, covered with skin and hair, but become bony nodules with age and fuse with the skull. The horns pop upright after about a week.

While I couldn't find any information about why giraffes have little horns, I suspect that the fact that baby giraffes have horns is relevant. When a baby deer or antelope is born, it doesn't have horns, so cannot damage the mother's body. I suspect that if the baby giraffe had longer horns, they wouldn't lie completely flat along the head and could damage the mother's womb. Obviously, if the womb were damaged, the baby could die. I'm sorry that this is purely speculation on my part, but as giraffe horns are so different from those of most other hoofed mammals, there must be a practical reason why they are so small.

I hope this helps.

All the best

Jonathan