Southern Africa (and London)-2104: 58. Days 16-18 & 20 (Aug 31, Sep 1, 2 & 4)

Toys-R-Us notwithstanding, the giraffe is not a cute little animal that can talk. It is the tallest land animal and is known for its extremely long neck and legs, ossicones (which we’ll talk about later) and distinctive coat patterns. In fact, the nine subspecies of the giraffe are classified based on their different coat patterns, which correspond to where each subspecies lives.

The giraffe subspecies that we saw was the South African giraffe and its coat pattern consists of dark, somewhat rounded patches with some fine projections on a tawny background color with spots extended down the legs and decreasing in size as they do so.

Each giraffe has a unique coat pattern which is recognized by other giraffes. And while the coat pattern does serve as camouflage, this is primarily important to calves. Adult giraffes depend on their size and ability to defend themselves (including by kicking). Lions are the major predator of adult giraffes while the calves are also subject to being taken by leopards, spotted hyenas, and wild dogs. Male giraffes darken with age.

By the way, the name giraffe comes from Arabic and means “fast-walker.” We’ll talk more about giraffes walking in the next post where we have videos of them walking and necking.

Since the giraffe’s most notable feature probably is the long neck, let’s look at that a bit. The neck can be 6-1/2 feet in length. And the length results not from more cervical vertebrae but for a lengthening of them after birth, with each being nearly a foot in length. It is important to note that the lengthening of the vertebrae occurs after birth as otherwise mothers would have difficulty giving birth to babies with the same neck proportion as adults.

With such a long neck, the heart of the giraffe has a lot of work to do to be sure blood gets to the head and brain. The heart of a giraffe weighs more than 25 pounds, is about 2 feet long, and provides about twice as much blood pressure as in a human.

So, why does the giraffe have a long neck? (other than serving as the answer for why giraffes only eat a little. Remember the joke in post 37? If not – look it up) Well, unsurprisingly when we come to a very unusual physical attribute, the reason is probably either the will of the deity or Darwinian natural selection, depending on your political leaning.

So, turning to natural selection, what would be the competitive advantage to a long neck that better enabled ancestral giraffes with long necks to reproduce and pass on their genes. While you think you might know, there are at least two theories and neither one is ideal.

Darwin himself suggested that the long neck meant that giraffes could eat higher up on the tree where other animals could not reach. And while there is evidence showing that giraffes eat more efficiently at the high level of trees, there is not good evidence as to how much time they spend feeding at such levels. There is also some evidence that long necked giraffes suffer greater mortality in drought conditions.

The other theory is that long necks are a secondary sexual characteristic giving males an advantage in necking contests (see next post) and thus an advantage in obtaining access to sexually receptive females. And males tend to have longer and heavier necks than females of the same age. But if this is the reason, then why do females have long necks at all? (Compare the peafowl in which the elaborate tail is only found in the peacock and not the peahen.)

Now, if someone has access to the explanation of the deity’s choice theory, I’d be happy to hear it.

Let’s look at some giraffes. Here are some along the Zambezi river, feeding at a rather low level.

Giraffes Feeding Along River

And here are some in the bush country away from water.

Giraffes Feeding Away From River - 1

Giraffes Feeding Away From River - 2

Here are two giraffes showing camouflage.

Giraffe Camouflage

The giraffe on the right, behind just some scrawny trees, is much less noticeable than the giraffe on the left.

And here is a view of a giraffe from the rear.

Giraffe from Rear

Now let’s look at another characteristic of giraffes. In the next photo you can see the horn-like structures on the top of the giraffe’s heads known as ossicones. These have a base of cartilage that has ossified and then is covered in skin.

Giraffes Showing Ossicones

The ossicones of the two giraffes on the left appear to be fully covered in hair while the giraffe on the right seems to have ossicones that are missing the hair on the end, almost as if it had been rubbed off – which it had. This is a very accurate way to judge either age or sex of a giraffe. If the ossicone has the hair on the end, the giraffe is either a female or a young male, as better seen here.

Ossicone on Female or Young Male

If the hair is missing from the end, then the giraffe is an adult male, as seen here.

Ossicone on Male

There is a reason for this “male pattern baldness” in giraffe ossicones. The ossicones are a weapon in combat. And here is a picture of several fairly young males engaging in this combat. Notice that the ossicones while not fully bald (thus the males are still fairly young), are already showing signs of wearing off that happens in combat. And in the middle of the photo is one giraffe that has turned its head to but against another one in combat.

Male Giraffes in Combat

OK. Enough of this violence (until the next post). Let’s end this post with some photos of a mother and calf (and remember that the mother is effectively the exclusive caregiver for the calves).