Rückenflossen

Rückenflossen, also known as dorsal fins, are external anatomical structures found on the back of many aquatic animals. Primarily observed in fish, these fins are located along the midline of the dorsal side of the body. Their primary functions vary depending on the species but generally include stabilization, preventing rolling, and assisting in maneuverability. In some fish, such as sharks, the dorsal fin can also be used for display or intimidation.

The shape, size, and number of dorsal fins can differ significantly among different species. Some fish possess a single dorsal fin, while others have two or even three. The fin can be supported by flexible rays or stiff spines, and the structure of these supports can be taxonomically important. For example, the presence and type of spines in the dorsal fin are often used by ichthyologists to identify and classify fish.

Beyond fish, dorsal fins are also present in some marine mammals like dolphins and whales. In these cetaceans, the dorsal fin's function is primarily for stabilization, similar to its role in many fish. However, unlike fish fins, cetacean dorsal fins are not supported by bony rays but are composed of fibrous connective tissue. Their presence and shape can also vary within cetacean species, sometimes serving as distinguishing characteristics. The term Rückenflosse is the German word for dorsal fin, encompassing this diverse group of structures across aquatic life.