Why are all marine animals, whales have barnacle parasites, but dolphins and killer whales don't?

The main reason is the species of toothed whales (Dolphinidae, beaked whales, physeteridae, etc. ) Swim fast. When barnacles are parasitic on whales, dolphins and killer whales, the biggest enemy is the current. If the parasitic fish swims fast, it is easy to be thrown down.

Moreover, some species hunt in strange ways (for example, Rachynchidae and Cetacidae will dive thousands of meters to hunt). Freshwater dolphins such as Asian puffer fish, baiji dolphin and Indian puffer fish live in fresh water, while parasitic organisms such as cetaceans and barnacles do not live in fresh water. And many small whales like to rub on the bottom of the sea.

Extended data:

The larvae of barnacles are nauplii, and after 2-3 weeks of development, they become glandular larvae, which are adsorbed and fixed on suitable attachments. The fixed preantral larvae are attached to the contact surface with tentacles, which is convenient for movement.

So it is called temporary adhesion; At this time, if the attached surface is suitable for attachment. The glandular larvae will change from temporary union to permanent union. After fixation, glandular larvae metamorphose into barnacles, which secrete barnacle gum on the surface of the attachment base, making the attachment more firm.

Barnacle gum was first secreted in liquid state, and then condensed into a colloid layer coupling the base plate and the substrate through self-assembly and cross-linking, which experienced a complex and orderly process. The polymerization process of adhesion between colloid and the surface of attached substrate makes colloid have greater cohesive strength and biodegradability.