Fish intelligence in paradise fish ("Macropodus opercularis") which avoid places where they have experienced a single attack by a predator and continue to avoid for many months. A number of studies have shown that fish can retain information for months or years. Anecdotally, channel catfish ("Ictalurus punctatus") can remember the human voice call announcing food five years after last hearing that call. Goldfish remember the colour of a tube dispensing food one year after the last tube presentation. Sockeye salmon still react to a light signal that precedes food arrival up to eight months since the last reinforcement. Some common rudd and
What Is a Nation? to the reasons based on race, geography, history and so on. They argue that Renan maintains his intellectual background but subtly, i.e. the arguments he explicitly used in "What is a Nation?" are not consistent with his thinking. The concept of "daily plebiscite" would be ambiguous. They argue that the definition is an opportunist idealization and it should be interpreted within the Franco-Prussian War and in the midst of the dispute concerning the Alsace-Lorraine region. What Is a Nation? "What is a Nation?" ("Qu'est-ce qu'une nation?") is an 1882 lecture by French historian Ernest Renan (1823–1892), known for the statements