[英语课]

Crocodile Ice Fish

 The scientific name of crocodile ice fish is Channichthyidae. Have you heard of it?  They are the best cold adapted animals on the planet, and have lived at between +2°C and -2°C for 5 million years (-2°C is the freezing point of sea water, being below zero because of the salt content of the water). They mainly eat krills, copepods, and other fish for food. They are the only known vertebrates without hemoglobin, so the blood is transparent and this gives them an unusual appearance, being ghostly white color, especially their gills. Their metabolism relies only on the oxygen in the liquid blood. It is believed that the crocodile fish can absorb oxygen from water through the skin directly. This approach is clearly very effective, because when the temperature reaches a minimum, the water can dissolve substantially all the oxygen. In the five kinds of crocodile ice fish, muscle myoglobin gene also disappeared except pink heart, leaving them only white.


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[MSL]

It is a very interesting animal.