Are Sharks and Dolphins Homologous or Analogous?

Sharks have earned the name of the most monstrous creature of the ocean, while on the other hand, Dolphins are considered to be the coolest species of ocean. Though both of these species seem to have similar morphological features, they don’t even have the same taxonomic class. Sharks and Dolphins have a brawns vs. brains war because the level of intelligence is quite elevated in dolphins than in sharks.

Although Sharks are a horrible nightmare for almost entire sea species but it is a fact of the matter that there is a single marine genre that most sharks are scared of; Dolphins. Dolphins can easily surpass sharks because of their physical features. Dolphins are slimmer and sleeker, with a vertically oriented tail that can provide a sufficient amount of mobility. It increases the tendency to move promptly when both species are supposed to be in a duel.

Whether you prefer to be in the Dolphins’ squad or Sharks’ squad, one thing for sure is that both of these are an incredulous class of animals that dominate the depths of the oceans. Looking for more information about Sharks and Dolphins, then stick here and scroll down!

In What Ways Sharks And Dolphins Are Similar?

Sharks and dolphins have a lot in common. Both these species have the same countershading in which their dorsal side is dark while the ventral part is brighter. As a result of this difference, they blend in with the ocean. If you look at them from the surface, their darker side will help in recognizing them, while in the depths of the ocean, a lighter shade eminent them in complete darkness.

Both sharks and dolphins are excellent swimmers. They both have dorsal fins that facilitate swimming at a very fast speed. They even have the same nutrition and rely on small marine animals for their nourishment. Additionally, they have a similar life span of about 20-30 years.

In What Ways Sharks And Dolphins Are Dissimilar?

Although both of these species resemble a lot with each other externally, there are more dissimilarities than similarities between sharks and dolphins. Let us have a look!

Sharks and Dolphins are from Different Classes

Although they have similar external characteristics, both have major differences. Sharks are fishes that belong to Class Chondrichthyes that are primarily of the cartilaginous endoskeleton. They lay eggs to increase their population. They are cold-blooded fishes. They contain a pair of very strong jaws. The skin is covered by tiny tooth-like scales called dermal denticles.

Dolphins, however, belong to the mammal kingdom, which is characterized by warm blood and maintaining their internal temperature wherever they go. In the same way as humans, they give birth to their young as opposed to laying eggs. They have an endoskeleton system similar to human beings. 

Even though dolphins have slim and sleeker body surfaces, the fascinating thing about dolphins is that they are born with body hairs that slowly and gradually fall off. Another interesting fact about dolphins is that they produce milk to nourish their young ones along with the long gestation period.

Marine Habitat and Social Behavior

Ocean depth is the primary habitat of sharks. They prefer to live underwater solitarily. They are very antisocial and love their lonesome zone. On the contrary, Dolphins spend most of their lives at the surface of the ocean because, being a mammal, they need to inhale fresh air at time intervals. They are super friendly marine animals which is the reason why they earned the name of the coolest living animal in the entire ocean.

Fins and A Way of Swimming

Sharks and Dolphins both have dorsal fins on the dorsal side and pectoral fins on the lateral sides. But a shark’s tail is vertically oriented, contradictorily dolphins have horizontally oriented caudal ends. Subsequently, both of these species are extremely skilled at swimming vertically and horizontally, respectively.

Breathing Through Gills and Lungs

Sharks are the typical marine species that are supposed to breathe through gills to have oxygen for compulsory life processes, just like any other aquatic creature. Conversely, being a mammal, dolphins have lungs to perform the crucial process of respiration. It is one of the main reasons that they devote most of their life span near the surface of the ocean.

Are Sharks and Dolphins from Divergent Line?

Sharks and Dolphins do not have similar anatomical features. Their internal body structures are quite dissimilar from each other. Neither do they have a different scale of functions that would include them in a category of homologous species, which confirms that they do not hold distinct evolutionary lineage. So, it is now certain that they are not from the divergent line of evolution.

Are Sharks and Dolphins from the Convergent Line?

Both of these classes have indistinguishable morphological features and common functions. Although their ancestral history does not match, they possess quite similar features. They have evolved from different phylogenetic lines, but environmental factors compelled them to adopt similar traits. So they are from the convergent evolutionary lineage substantiating that they are analogous to each other.


Sharks, as well as Dolphins, are assumed to be one of the dominating marine creatures. Sharks are the top apex predators of the marine world, while Dolphins are often viewed as the most enchanting and human-friendly genre of the ocean. They have a lot to resemble and a lot to vary from each other. Their internal structures are quite distinguishable with similar functions that make them a typical constituent of the analogous category.

About the author

Yumna Ahmad

An experienced content writer, photographer, and avid reader amazed by the sea world and its creatures. I am lettin people become fascinated with the ocean planet through my writings.