Cow shark usually lives in freshwater areas and are found in the deep waters of the Amazon River tributaries like Iquitos in Peru, a seaport 4.000km. These fish can feel the changes the salinity of the surrounding water, and can be adapted according to the new environment. This fish has a length of about 3.3 meters, weighs 312kg. Like other sharks, we have countless triangular sharp teeth and strong jaws with a bite force of up to 589kg. Cow shark is considered one of the most dangerous sharks in the world.