Fig. 43.—Giraffe showing at A and B, hair-patterns of a remarkable kind at the place where the main movements of the neck occur.
Living mainly in dry sandy regions giraffes find their food exclusively in leaves plucked from trees, and are said by some authorities to exist for a long period without drinking, but an interesting account quoted by Lydekker from Selous should be mentioned here. Selous writes that on a certain occasion he reached camp “a little before sundown, just in time to see three tall, graceful giraffes issue from the forest a little distance beyond, and stalk across the intervening flat, swishing their long tails to and fro, on their way down to the water. It is a curious sight to watch these long-legged animals drinking, and one that I have had several opportunities of enjoying. Though their necks are long, they are not sufficiently so to enable them to reach the water without straddling their legs wide apart. In doing this, they sometimes place one foot in front, and the other as far back as possible, and then by a series of little jerks widen the distance between the two, until they succeed in getting their mouths down to the water; sometimes they sprawl their legs out sideways in a similar manner.” Lydekker adds that this position has to be assumed not only when drinking, but likewise when the animal desires to pick up a leaf from the ground or on the rare occasions when it grazes. This habit so graphically described is the one which alone concerns my subject. The patterns of hair peculiar to the giraffe need a short description.
Hair Patterns.
Fig. 44.—Giraffe in the act of drinking or browsing off the ground.
Fig. 43 shows a whorl (B) at the side of the neck on a level with the prominent spines of the seventh cervical and first dorsal vertebræ. It lies exactly over a spot which may be well called a “critical area,” for an important hinge of the whole mechanism of the giraffe’s great neck is situated here. Though the remarkable length of its neck is intimately associated with its daily needs for protection against enemies and the supply of food from high-placed branches of trees, it forms a real obstacle to the less important need of obtaining water to drink or food from the ground as Selous and Lydekker show. The protective value of the neck is picturesquely described by Mr. Beddard when he speaks of it as the giraffe’s watch-tower, whence its keen eyesight surveys the surrounding country for its enemies. But its attitude in drinking, Fig. 44, gives a vivid idea of the play of forces which takes place at the great hinge between the neck and the trunk, and at this point the whorl has been produced on the skin in the course of its laborious efforts to supply itself with water. The absence of any other whorl or reversed hair on the whole of its neck and trunk is most significant from the point of view of the dynamics of hair.
The second departure from the normal direction of hair is found on the prominent portion of the spine, and it lies over this hinge-area. In Fig. [44] is shown the mane proceeding along the whole of the neck in the normal downward direction, and the arrows indicate the way in which it becomes suddenly reversed at the critical point and the lowest portion of the mane stands up and points upwards. This change is shown by the two arrows whose points meet one another, and the facts of its occurrence, here and nowhere else, at once suggest that the habit which produced the whorl on the side of the neck has also contributed to the change in the direction of the mane. The pattern here is precisely of the same order as that of the cow’s neck which we saw to be caused by its habit of browsing off the ground.