Because water is stored up in the separate chambers of the stomach, apart from the solid aliment, so that the animal can feed, without consuming all its drink. It is thereby able to retain water to satisfy its thirst while travelling across hot deserts, where no water could be obtained.
1066. Why do woodpeckers "tap" at old trees?
Because by boring through the decayed wood, with the sharp and hard bills with which they are provided, they get at the haunts of the insects upon which they feed.
1067. Why are woodpeckers' tongues about three times longer than their bills?
Because, if their bills were long, they would not bore the trees so efficiently; and when the trees are bored, and the insects alarmed, they endeavour to retreat into the hollows of the wood; but the long thin tongue of the woodpecker fixes them on its sharp horny point, and draws them into the mouth of the bird.
1068. Why have the Indian hogs large horns growing from their nostrils and turning back towards their eyes?
Because the horns serve as a defence to the eyes while the animal forces its way through the thick underwood in which it lives.
1069. Why have calves and lambs, and the young of horned cattle generally, no horns while they are young?
Because the presence of horns would interfere with the suckling of the young animal. When, however, it is able to feed itself by browsing, then the horns begin to grow.