There is a story that has been passed on from several generations of rangers at Londolozi about a guest that repeatedly kept asking a ranger whether giraffes eat meat:
Guest: “Is that giraffe going to eat those impala lambs?”
Ranger: “No, giraffes are herbivores. They will not eat impala. Ever.”
Guest: “Is that wildebeest going to be okay with that huge giraffe so close? Surely it’s going to attack and eat the wildebeest?!”
Ranger: “As you can see, the giraffe is using its long tongue to pull the leaves off the tree. They are strictly browsers that eat leaves only. They are definitely not going to attack the wildebeest, or any other animal for that matter…”
As the vehicle rounded the very next corner, a giraffe raised its long neck up from the ground. It had a large chunk of bone in its mouth. “I thought you said giraffe only eat leaves!” exclaimed the guest, angrily. Nothing the ranger said could have saved herself in that moment…
The phenomenon is referred to as osteophagia, which literally means, to eat bones. Giraffe have been recorded chewing on bones more so than any other wild animal. There are several reasons for this, but one main one: the ratio of skeleton to body mass is much higher in giraffe compared to similar sized mammals (ie. they have a high total bone mass compared to body mass). In addition, they have a fast growth rate. Both of these points mean that giraffe require high levels of calcium and phosphorus.
Calcium is derived from the leaves that giraffe eat. Phosphorus is not as readily available, particularly in winter. Thus, as much as we jump to the conclusion that giraffe are supplementing their calcium intake by chewing and swallowing bone fragments, it is in fact an effort to maintain the ratio of calcium to phosphorus.
Osteophagia is much more common in winter when plants are not as nutrient rich, but it has been observed year-round. Simply put, giraffe are upping their mineral intake through eating small pieces of bone, driven by a deficiency of those minerals.
The irony in this series of images is that the giraffe clearly don’t know what species the bone upon which they are chewing is derived. Let’s just say that a pride of lions enjoyed feeding on a giraffe in that exact spot a few years ago…