Difference Between Shark and Dolphin

Shark vs Dolphin

Living in the same ecosystem, sharks and dolphins are two different types of animals. Shark is a cartilaginous fish, whereas the dolphin is a mammal live, in the marine ecosystem. Both these species have got the peoples’ attraction for their magnificence, intelligence, playfulness, fearsomeness…etc. Sometimes, there may be instances to identify dolphins as fish as they live in water. Therefore, it is important to discuss the differences and similarities between sharks and dolphins in a Zoological perspective.


By the name of  shark, it sounds dangerous, and that is because of their carnivorous food habits. This cartilaginous fish (Class: Chondricthyes) is a diverse group of animal with about 440 species. Sharks can live in deep as well as shallow waters, and their sizes also vary drastically between 15 centimetres (a deep sea shark) and 12 metres (whale shark). They are extremely well adapted for a predatory lifestyle with sharp teeth, strong jaws, highly streamlined body, keen eyesight, excellent olfactory sense, sharp hearing ability, and electroreception to sense other animals. They indeed have the most developed electro sense among animals. Sharks are the top predators in the marine ecosystem. They can prey on any animal within their grasp. Presence of dermal denticles (made of collagenous fibres) and their arrangement surrounding the body provide shark an outer skeleton. Swimming muscles are attached to those denticles and that saves energy while producing very rapid movements in the shark. There is another important feature in sharks, which is the shape of the tail or the caudal fin. The shape of tail varies within species (e.g. Tiger shark, Great white shark, Coockiecutter shark). Sharks do not have swim bladders, but the liver is large and filled with oil and their cartilaginous skeleton is light, providing them a great buoyancy. Respiration occurs through the gills and most sharks live about 20 – 30 years.


These popular mammals live in the sea like their relatives, whales. There are about 40 species of dolphins that are distributed throughout the world. Mostly, the dolphins are found in shallow waters. The size of a dolphin can vary within one to ten metres of length, and from 40 kilograms to 10 tonnes of weight. Dolphins are the largest group of the Order: Cetacea. They mostly prefer fish and squids for their food. Dolphins are intelligent, and they herd together most of the time to restrict the fish schools into small volumes and feed on them. Sometimes they chase the fish into shallow waters so that the catching would be easier, which method is called the corralling. Their streamlined body makes them fast swimmers. However, dolphins breathe fresh air from their lungs. Sleeping behaviours have also been observed, and their remarkable whistling and whining sounds have been recorded. The usual lifespan of a dolphin is about 20 years.

What is the difference between Shark and Dolphin?

- Dolphins possess the mammalian features, whereas sharks are a group of fish.

- Sharks are more diversified than dolphins.

- Sharks are notorious hunters, whereas dolphins are not so.

- Dolphins breathe fresh air by their lungs, while sharks extract Oxygen from water through gills.

- Dolphins prefer shallow waters, but sharks do not seem to prefer a particular habitat in the sea, and instead they are found everywhere.

Despite all these differences, both these animals have been a top attraction of people.