Almost every whale suffers from barnacles. Why can barnacles be parasitic on whales but not on sharks?

Barnacles are marine organism that belongs to the phylum Arthropoda.

The body of barnacles is shaped like a tube, with a hard outer shell formed by calcium, and its interior has several tube-like structures that form a complex system of waterways.

Barnacles have a sieve-feeding lifestyle, feeding on plankton and playing an important role in the marine ecosystem.

Barnacles usually live in the ocean and attach themselves to various hard objects such as rocks, crustaceans, the bodies of marine organisms, and marine plants.

Barnacles have relatively little impact on humans because they rarely come into direct contact with them. However, they have an important impact on other organisms.

For example, they can provide habitat for other marine organisms, such as fish and crustaceans. In addition, they can provide support for coral reefs, helping to maintain the reef's ecosystem balance.

However, barnacles can also be harmful to certain organisms.

Barnacles can grow parasitically on the skin surface, digestive tract, and other parts of the whale. In this case, barnacles may cause several hazards to whales.

1. Skin breakage and irritation: barnacles parasitizing the skin surface of whales may cause skin breakages and skin reactions, such as rashes and itching. This may affect the survival status of the whale.

2. Obstruction of the digestive tract: barnacles may parasitize the whale's digestive tract, causing obstruction in these areas and thus affecting the whale's digestive function.

3. An Excessive number of parasites: If barnacles parasitize too many whales, they may affect the whales' nutritional intake and energy consumption, thus affecting their health and survival.

Barnacles can indeed be harmful to whales, but most whales can remove barnacles from their bodies by brushing, rubbing, and diving.

Why can barnacles parasitize whales, but not sharks?

The answer to this question has to do with the different physiology of whales and sharks. Whales

The skin of a fish is softer and has no scales, while the skin of a shark is harder and covered with scales.

The whale's skin has many capillaries and sweat glands that provide the necessary nutrients and moisture for the barnacles. The barnacles can enter the whales through their skin and parasitize them internally.

In contrast, sharks have very hard skin covered with scales that make it difficult to enter their bodies through their skin.

Sharks have no capillaries or sweat glands on their skin to provide the necessary nutrients and water for barnacles, making it almost impossible for barnacles to parasitize on sharks.