Rockhopper penguin is one of the world’s most numerous penguin populations, it is estimated that the population declined by some 30 percent over the final 30 years of the 20th century. The cause of this decline is mainly unknown, but scientists have speculated that humans are involved, mostly by commercial overfishing, oil exploitation, and pollution. Recent research has shown that rockhopper penguin population declines with changes in ocean surface temperature, indicating a direct impact from climate change. These activities have depleted much of the rockhopper penguin’s food supply and raised the sea surface temperatures, and because this species is geographically isolated to
What Is a Nation? and continues to be invoked. Political historian Karl Deutsch, in a quote sometimes mistakenly attributed to Renan, said that a nation is "a group of people united by a mistaken view about the past and a hatred of their neighbours". Benedict Anderson's 1983 work Imagined Communities, which states that a nation is an "imagined political community", argues that Renan contradicts himself when he says French people must have forgotten the St. Bartholomew's Day massacre, yet does not explain what it is. In other words, Renan assumes that all his readers will remember the very massacre he says they have forgotten.