No, because they can't. Some dolphins and other marine mammals can live in fresh water.
Polar bears DO NOT eat snow. It takes too much of their body's energy to convert the snow into water. Polar bears get all the water they need from the food they eat.Actually they do eat snow. There isn't many open water sources, let alone fresh water, available where they roam, and even the prey they eat doesn't provide sufficient water for them to live off of alone.
Fresh and salt water are very different for one key reason, fresh water doesn't contain salt and salt water obviously does. There are different flora and fauna in fresh and salt water for this reason.
on fresh salt water
Salt water is water that has salt in it and it is found in oceans. Fresh water does not have salt and is found in rivers and lakes.
salt water
Salt water is basically just fresh water with salt mixed in.
Salt water is basically just fresh water with salt mixed in.
Salt water contain salt, fresh water is practically pure.
Peru has both Fresh and Salt water. Salt Water in the ocean and Fresh in lakes, streams, and on the mountains.
Salt water has salt water in it and is bad for you, fresh water has no salt water in it and is good for you.
There are both salt water and fresh water crocs.