Plenty of poets wrote them, but the most famous of all is John Milton's  Lycidas . Like all typical pastoral elegies, Milton mourns the loss of his best bud (who died in a shipwreck). But he also compares him to a shepherd and describes the ways in which nature mourns his loss, too.
The Banff longnose dace, a small minnow, was recently declared extinct. It failed to compete with the guppies, swordtails, sailfin mollies and other tropical fish that had been released in the warm marsh below the famous hot springs by tourists and national park officials.
Credit: Mauricio Anton. Saber-toothed cats apparently did not go extinct for lack of prey, contradicting a popular explanation for why they died off, fossil evidence now suggests. Even near their extinction, saber-toothed cats likely had enough to eat, researchers noted. Saber-toothed cats, American lions, woolly mammoths and other giant creatures once roamed across the American landscape. However, at the end of the late Pleistocene about 12,000 years ago, these megafauna went extinct, a die-off called the Quaternary extinction.