Some ducks need a sip of water before they go into the water. What's the use of this saliva?

Ducks will drink water before entering the water, because:

One is to tell whether there are edible creatures in this water by drinking water. The duck's drinking action can actually filter out the edible microorganisms and algae in the water. eat small fish Shrimp instinctively knows whether there is anything to eat in the water from the taste of the water, so the duck can't wait to drink water as soon as it enters the water.

The second is to test the water temperature by drinking water to identify whether there is the smell of dangerous creatures. Give a warning first and retreat in time if there is danger (ducks are domesticated in the wild and retain their instincts). Sometimes ducks will go into the water to cool down in summer, but in some shallow waters, the water temperature will be very high when they are exposed to the sun, so ducks should test the temperature and decide whether to go into the water. The water is too cold in winter, and the water temperature is low. Small fish and shrimp are all in deep water, so you can't eat them in water! Ducks drink water before entering the water to determine whether the water temperature is appropriate, because the water temperature can be tested to see if it is suitable for playing in the water.

I think this is to measure the temperature of water and see if there is anything that can be discharged. It is to test the water temperature by drinking water, to identify whether there is the smell of dangerous creatures, to alert the snake first, and to retreat in time if there is danger. I think it's to test the water temperature. Ensuring the water temperature is within the normal range may be to see if there is anything threatening your life in the water. It seems that you can tell the water quality and know if there is food. I think this is to feel the temperature and cleanliness of water.

Distinguish whether there is the smell of dangerous creatures, alert the snake first, and retreat in time if there is danger (wild ducks are domesticated and keep their instincts). Sometimes ducks will go into the water to cool down in summer, but in some shallow waters, the water temperature will be very high when they are exposed to the sun, so ducks should test the temperature and decide whether to go into the water. It's not good if the water is too cold in winter. The water temperature is low, and all the small fish and shrimps are in deep water.