The sand soil and water in the Yellow River Estuary eco-tourism area is suitable for the survival of crabs. In summer night, crabs go out to cross the road in an unbridled way. The mud-flat crab catching in the scenic area is an ideal place for tourists with children or interested in catching crabs.
Crabs are crustaceans. Their body is protected by hard shell and they breathe by relying on gills. Crabs like to survive in clay, sand or sub-sand environment with adequate drainage, good ventilation. Every time, the female crabs will lay a lot of eggs, up to several million or more.
Crabs rely on geomagnetic fields to judge the direction. As the geomagnetic north-south pole has a number of reversals, resulting in the inadaptability of a number of creatures, or even cause extinction. Crab is an ancient retrograde animal; its inner ear has a small magnet, which is very sensitive to geomagnetism. However, the reversed magnetic field makes the small magnet in the crab body lose the original orientation. To survive in the geomagnetic field reversal, the crab makes the practice of "countering changes with consistency", neither advances nor retreat, but goes horizontally.