The breath is the process by which living oxygen obtained. This respiration can be pulmonary , branchial, tracheal or cutaneous .
The animals that breathe through the gills are aquatic animals of fresh and salt water, among which are several species of crustaceans, worms, amphibians , mollusks and all fish. For example: the shark, the crab, the octopus.
Gill respiration is carried out by the gills or gills, which are the respiratory organs that filter oxygen from the water into the blood and tissues. This oxygen is vital for cellular respiration. The gills filter oxygen and expel carbon dioxide into the environment.
Types of gills
The gills are tissues formed by small sheets or thin filaments with blood vessels adapted to the constant movement of animals in their aquatic environment. They are usually located in the upper part of the animal’s body and can be external or internal.
- External gills. They occur in invertebrate animals or at the beginning of the evolution of some animals. They are primitive and simple structures that are in direct contact with the environment. This has a number of disadvantages, as they can be easily damaged and make locomotion difficult. For example: the sea urchin and the larvae of some amphibian species have external gills.
- Internal gills. They occur in larger aquatic animals. They are partially sheltered in cavities which gives them protection. For example: bony fish (tuna, cod, mackerel) have an operculum (fin that protects the gills).
Examples of animals that breathe through gills
| Clam | Tuna | Axolotl |
| Cod | Catfish | Shrimp |
| Crab | Trout | Shark |
| Piranha | Sea urchin | Stingray |
| Spider crab | Locust | Swordfish |
| Sturgeon | Shrimp | Oyster |
| Silverside | Hippocampus | Squid |
| Octopus | Salamander | Sea slug |
| Eel | Sea hare | Croaker |
| Sardine | Brunette | Mussel |
| Barracuda | Marine mollusks | Giant tube worm |
| Carp | Tintorera | Fire worm |
| Mojarra | Cockle | Water fleas |
| Freshwater snail | See | Hake |