Natrix is a genus of snakes commonly known as water snakes. They are primarily found in North America and Europe, inhabiting freshwater environments like rivers, lakes, and marshes. These non-venomous snakes are known for their excellent swimming abilities and often have a diet consisting of fish and amphibians. There are several species within the Natrix genus, including the Natrix natrix, or the grass snake, which is recognizable by its distinctive yellow or white collar behind the head. Natrix snakes are generally harmless to humans and play an important role in their ecosystems by controlling prey populations.