[You must be registered and logged in to see this image.]The world would be a smaller place without its megaherbivores - and particularly those sky-scraping browsers, giraffes. Here are seven things you need to know about these fussy eaters.
1. Giraffes are born with their ossicones (horns) lying flat against their heads. Later, the ossicones fuse to the skull, harden and grow. In adult males they become formidable weapons, worn bare of skin at the tips – old bulls may even have patches of bare bone elsewhere on their massive, craggy heads.
2. Much of the moisture that giraffes need is produced as they metabolise their food but they also drink water directly – they shuffle awkwardly until their front legs are splayed and they can reach the water surface.
3. A large body size means a long gestation period. Female giraffes carry their young for 15 months – but since they can breed all year round, they do not need to ‘resynchronise’ with the seasons each time they give birth.
4. Giraffes require large quantities of calcium and phosphorus to build their skeletons. After weaning, they derive most of these minerals from their food, but they also chew on carcass bones (a behaviour known as ‘osteophagy’).
5. A fully grown giraffe can raise or lower its head by up to 5m and might pass out were it not for a dense network of fine capillaries (the ‘rete mirabile’) that cushions its brain against rapid changes in blood pressure.
6. Giraffes are probably the world’s largest pollinators, transferring genetic material on their muzzles from the flowers of one tree to those of another.
7. The giraffe family contains only one other species: the rare okapi. This forest-dweller has a shorter neck – like the extinct species from which both it and giraffes are thought to have evolved.
Wed Sep 05, 2012 8:29 am
