Fauna of Europe of the Baltic Sea has led to the evolution of many slightly divergent species, such as the Baltic Sea herring, which is a smaller variant of the Atlantic herring. The most frequent benthic species are "Saduria entomon" and "Monoporeia affinis", which is originally a freshwater species. A great part of its bottom is anoxic and without animal life. The Baltic Sea and North Sea are also home to a variety of marine mammals (common seals, grey seals). Europe contains several important freshwater ecoregions, including the heavily developed rivers of Europe, the rivers of Russia, which flow into the Arctic, Baltic,
Parting of the Waters Creek waters flow either to the Atlantic Ocean via Atlantic Creek and the Yellowstone, Missouri and Mississippi Rivers, or to the Pacific Ocean via Pacific Creek and the Snake and Columbia Rivers. In the marshy area of Two Ocean Pass adjacent to Parting of the Waters, water actually covers the Continental Divide such that a fish could swim from the Pacific Ocean to the Atlantic Ocean drainages. In fact, it is thought that this was the pass that provided the route for Yellowstone cutthroat trout to migrate from the Snake River (Pacific) to Yellowstone River (Atlantic) drainages. This site received