Freshwater crab Nature (IUCN); of the species for which data are available, 32% are threatened with extinction. For instance, all but one of Sri Lanka's 50 freshwater crab species are endemic to that country, and more than half are critically endangered. Freshwater crab There are around 1,300 species of freshwater crabs, distributed throughout the tropics and subtropics, divided among eight families. They show direct development and maternal care of a small number of offspring, in contrast to marine crabs which release thousands of planktonic larvae. This limits the dispersal abilities of freshwater crabs, so they tend to be endemic to small areas.
Arctic National Wildlife Refuge Wildlife Refuge is the only refuge that regularly dens polar bears in that local region, and contains the most consistent amount polar bears in the area. The Arctic basin is the shallowest ocean basin on Earth. It is the least salty, because of low evaporation and large current of freshwater from rivers and glaciers. River mouths and calving glaciers, are continually moving ocean currents contribute to a unique marine ecosystem in the Arctic. The cold, circulating water is rich in minerals, as well as the microscopic organisms (such as phytoplankton and algae) that need them to grow. Marine animals thrive