Aesop's Fables (1884)
12. The Lion and the Boar.
On a summer day, when the great heat induced a general thirst, a Lion and a Boar came at the same moment to a small well to drink. They fiercely disputed which of them should drink first, and were soon engaged in the agonies of a mortal combat. On their stopping on a sudden to take breath for the fiercer renewal of the strife, they saw some Vultures waiting in the distance to feast on the one which should fall first. They at once made up their quarrel, saying: "It is better for us to make friends, than to become the food of Crows or Vultures, as will certainly happen if we are disabled."
Those who strive are often watched by others who will take advantage of their defeat to benefit themselves.
Aesop's Fables: A New Revised Version From Original Sources (translator not identified), 1884 . Illustrations by Ernest Henry Griset (1844-1907), John Tenniel (1820-1914) and Harrison Weir (1824-1906). Available online at Project Gutenberg.