It is always surprising to me when I find a very well-known animal that I haven’t blogged about. I suppose I do try to find weird and wonderful animals to write about, so it makes sense that I would skip over some obvious ones. Still, I think it’s a bit of a crime that I haven’t written about giraffes yet.
While it used to be thought that there was only one species of giraffe, recent studies have shown that there are actually four to six distinct species of giraffe. All species can be found in Africa, in scattered pockets from Chad to South Africa, and from Niger to Somalia. Giraffes live in savannah, grasslands or open woodlands, and are particularly fond of anywhere where Acacia trees grow.
Giraffes have both the title of World’s Tallest Mammal and Largest Ruminant. Male giraffes can reach heights of 5.7 meters to their horns, and can weigh almost 2,000 kg. Females are smaller, with the largest female recorded at 5.17 meters, and the largest weight recorded at 1,180 kg. Giraffes are famous for their fun, spotted coats. These coats help giraffes camouflage, and vary depending on where the giraffe lives.
One of the coolest things about giraffes is their prehensile tongues. These are around 45 cm long, and are black. It is thought that giraffe tongues are coloured in this way to prevent the tongue from being sunburnt while the giraffe is feeding. Giraffes feed on trees, shrubs, fruit and grass, preferring the thorny trees in the subfamily Acacieae. Their lips, tongues, and inside of their mouths have thick papillae to protect against the thorny food they eat. Giraffe necks allow these animals to feed at a greater height than their competitors, as they can feed at heights of 4.5m, while their largest competitors can only reach 2m in height.
While the giraffe’s long neck lets it eat leaves and branches in high places, this has its disadvantages. Giraffe necks can reach lengths of up to two and a half meters, and result from elongated vertebrae, not extra vertebrae. These long necks mean that giraffes have to bend down quite a ways to get water — in fact, giraffes can only drink if they splay their front legs or bend their knees. If you think you get dizzy after bending down and standing up suddenly, just imagine how giraffes feel.
Actually, giraffes have a way of dealing with this problem. They have a special area of closely packed veins and arteries in their necks, known as a rete mirabile. This prevents too much blood from flowing into the brain when they lower their heads, and when the giraffe stands back up, the vessels constrict and send blood to the brain, preventing fainting. Giraffes’ hearts have to do a lot more work than other mammals’ — to keep a steady blood flow to the brain a giraffe’s heart has to create double the blood pressure that a human heart would need to. Because of this, giraffes’ hearts are very large, weighing 11 kg and having walls as much as 7.5 cm thick.
Giraffes live in groups, though these are somewhat loose, with individuals leaving and rejoining the group. Females are more social than males, and males will engage in ‘necking’ to establish dominance. There are two forms of necking, low and high intensity. In the first instance, male giraffes simply lean against one another, rubbing their necks against one another to see who gives way first. In high intensity necking, the giraffes activity swing their necks at one another, trying to hit each other with their horns. These fights can last over half an hour, and though injuries do not usually occur, the blows can break jaws, necks and cause death.
Mating in giraffe happens during the rainy season. A bull male will approach a female in estrus, rubbing his head on her hindquarters and resting it on her back. He will then lick her tail and raise a foreleg to ask if she is ready for copulation. If she is, she will circle her suitor and then raise her tail, at which point the male will mount the female.
Females give birth to a single calf (twins occur rarely) after a 450 day gestation. Being born must be an unpleasant experience for any creature, but it’s particularly rough for giraffe calves: females give birth standing up, so the calves drop two meters to ground after leaving the womb. Calves are weaned after twelve to sixteen months; females reach sexual maturity at three or four years of age, while males are mature at four to five years, though they only start to breed at seven years of age.
For a long time giraffes have been thought to have had a relatively stable population. However, in 2016 their status was changed from Least Concern to Vulnerable, thanks to habitat destruction and hunting. Giraffes are protected throughout most of their range, so hopefully we can stop these funny guys from becoming endangered.