Risso’s Dolphins

Dolphins are among the most fascinating and intelligent creatures on the planet. These marine mammals are known for their playful behaviour, acrobatic skills, and highly social nature. With over 40 different species of dolphins found in waters around the world, these animals have captured the attention and admiration of humans for centuries. From the acrobatic spins of the bottlenose dolphin to the unique pink coloration of the Amazon river dolphin, each species has its own distinct characteristics that make them fascinating to study and observe.


Sl No.CharacteristicsDescription
1Common NameRisso’s Dolphin
2Scientific NameGrampus griseus
3Length9 to 12.5 feet
5Average weight 300 to 500 kg 
6Food habitssquid ,fish, crustaceans,cephalopods
7Habitatboth warm and temperate waters worldwide, primarily in offshore 
8Any interesting facts about them 

Risso’s dolphin (Grampus griseus) is a species of marine mammal that belongs to the family Delphinidae. They are known for their distinctive appearance, which includes a large, bulbous head, a tall dorsal fin, and a greyish-white body colour that becomes darker with age.

In terms of sexual dimorphism, male and female Risso’s dolphins look quite similar in terms of size and coloration. They both typically measure between 2.7 to 3.8 metres (9 to 12.5 feet) in length, and weigh between 300 to 500 kg (660 to 1,100 lbs).

One unique characteristic of Risso’s dolphins is the scarring on their bodies, which is believed to be caused by interactions with other dolphins, squid, or other prey. These scars are particularly prominent on older individuals, and can cover a large portion of their bodies. As a result, older individuals can appear almost entirely white, with the scars giving them a distinct “etched” or “pitted” appearance.

Risso’s dolphins are also known for their vocalisations, which include clicks, whistles, and pulsed sounds. They are a social species, and are often seen in groups of 10 to 30 individuals, although larger groups of up to 200 have been reported. They are found in temperate and tropical waters around the world, and are known to feed on squid, fish, and crustaceans.

Food Habits

Risso’s dolphins are known to be opportunistic feeders, and their diet varies depending on their location and the availability of prey. They primarily feed on squid but are also known to consume fish, crustaceans, and other cephalopods. They have been observed using a unique hunting strategy, in which they chase squid to the surface of the water before feeding on them.


Risso’s dolphins are found in both warm and temperate waters worldwide, primarily in offshore areas. They are known to inhabit deep waters, as well as coastal areas such as bays and estuaries. They prefer waters that are at least 200 metres (660 feet) deep, but can also be found in shallower waters.

Vulnerable Species

Risso’s dolphins are not currently classified as vulnerable globally by the International Union for Conservation of Nature (IUCN), but the status of this species in India is not well known. There is very limited information available on the population size and distribution of Risso’s dolphins in India, and as a result, it is difficult to determine the level of threat they may be facing.

However, like many other marine mammal species, Risso’s dolphins are known to face a range of threats. These include habitat loss and degradation, accidental entanglement in fishing gear, pollution, climate change, and hunting for meat or for use in traditional medicines. In addition, Risso’s dolphins are sometimes targeted in direct hunts in some parts of the world.

In India, fishing activities are likely to be the most significant threat to Risso’s dolphins, as they can become accidentally entangled in fishing nets, and may also experience competition for prey from commercial fishing activities. Pollution from human activities may also pose a risk, as it can affect the quality of the dolphins’ habitat and the availability of prey.

Given the limited information available on the population status of Risso’s dolphins in India, it is difficult to estimate their numbers. More research is needed to better understand the distribution and abundance of this species in Indian waters, as well as the specific threats they may be facing.

Protected Areas

There are several national parks and wildlife reserves in India that are known to be home to a variety of marine mammals, including Risso’s dolphins. However, it is important to note that Risso’s dolphins are not the primary focus of conservation efforts in these areas, and they may not be present in all of them.

Gulf of Mannar Marine National Park in the Gulf of Mannar in Tamil Nadu is home to a variety of marine species, including Risso’s dolphins, as well as sea turtles, coral reefs, and a diverse array of fish.

Mahatma Gandhi Marine National Park in the Andaman and Nicobar Islands, this marine national park is known for its coral reefs and rich marine life, which includes Risso’s dolphins, as well as dugongs, sea turtles, and a variety of fish and crustaceans.

Marine National Park, Gulf of Kutch in the Gulf of Kutch in Gujarat, is home to a variety of marine mammals, including Risso’s dolphins, as well as dugongs, sea turtles, and several species of whales and dolphins.

Conservation of the Species

Protecting the natural habitats of these dolphin species is crucial. This includes maintaining water quality, preventing pollution, and regulating the use of river systems, estuaries, and coastlines. 

Human activities such as fishing, boating, and development can have a significant impact on dolphin populations. Reducing the impact of these activities by regulating fishing practices, reducing noise pollution, and minimising boat traffic can help to preserve dolphin populations. 

Raising awareness of the importance of these dolphin species and their habitats can help to generate support for conservation efforts. Education programs can be implemented for local communities, schools, and tourists to teach them about the importance of these species. 

Conducting research and monitoring programs can help to better understand these species and their habitats. This information can be used to develop effective conservation strategies and monitor the success of these efforts over time. Effective conservation efforts will require collaboration and partnerships between various stakeholders, including government agencies, NGOs, local communities, and researchers. By working together, these groups can develop and implement effective conservation strategies to protect these dolphin species. 

With the increase in marine tourism activities such as boat rides and water sports, it is important to regulate these activities in a manner that ensures the safety and conservation of dolphins. This can be done by enforcing strict guidelines on boat traffic, keeping a safe distance from dolphins, and avoiding activities that can cause stress or harm to dolphins. 

Pollution can be extremely harmful to dolphin populations. This includes plastic pollution, chemical pollution, and noise pollution. Reducing pollution levels in the environment can help to protect these species and their habitats.


In conclusion, the conservation of these dolphin species is critical to maintain the biodiversity of our planet and the health of aquatic ecosystems. We must take concerted efforts to protect these intelligent and charismatic creatures from habitat loss, human impact, pollution, and other threats. By implementing the strategies mentioned above, we can ensure the long-term survival of these unique species and the preservation of their habitats for future generations.

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