Traditional Culture Encyclopedia - Weather inquiry - When is the best observation time for Qinzhou white dolphins?
When is the best observation time for Qinzhou white dolphins?
Among all kinds of fishing boats, white dolphins especially like to feed behind double tugboats, and the dolphins behind double tugboats are much larger than others. At least 20 different species of fish belonging to 13 families were found in the stomachs of dolphins. The largest number are anchovies, asparagus and herring. Among them, white dolphins like to eat lionfish (Collichthys lucida) best, followed by? Fish (Johnius spp) and yellow croaker (Thryssa spp).
The feeding and digestive system of Chinese white dolphins is completely consistent with that of terrestrial mammals, including teeth, esophagus, stomach, liver, spleen and intestine. Adult dolphins have 125~ 135 conical teeth in the upper and lower jaws, which are sparsely arranged. Their function is not chewing, but hunting. The feeding object is mainly freshwater fish in the estuary, which can be swallowed quickly without chewing. The stomach contents of dolphins were dissected and analyzed, mainly including spiny-headed lizard, Coilia ectenes and grouper. The common species in the Pearl River Estuary are silver pomfret, black pomfret, whitebait, dragon head fish and large yellow croaker, which mainly feed on small and medium-sized fish.
Like terrestrial mammals, Chinese white dolphins have developed lungs and breathed with them. The external breathing hole is half-moon-shaped, opening at the top of the forehead. When breathing, the head and back are exposed to water, and the oxygen in the air is directly breathed, and the jet sound of "Ji Ji-"is issued.
Chinese white dolphins have small eyes, located on both sides of the head, black eyeballs and poor eyesight. They mainly rely on the echolocation system to identify the position and direction of objects. There is an air bag under the nostril, which makes a sound by opening and closing the stuffy meat. This sound line is concentrated in the unique organ composed of fat at the forehead bulge and emitted at a certain frequency. Signals of different frequencies reflected from different objects are received by the groove formed by the fat in the lower palate of dolphins and introduced into the inner ear for positioning. Although this echolocation system is very complicated, its response is very fast and accurate. It can measure the size, shape, density structure and properties of the object in front, and make judgments and reactions. This special function of dolphins has been studied in bionics by life science departments and military departments.
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