Irrawaddy dolphin

Classification

Irrawaddy dolphins are a very interesting type of dolphin. Scientists have estimated that there are only 92 left in the ocean. These types of dolphins are mammals meaning they are warm blooded, feed their young milk and have fur. Although, only baby dolphins have fur then they loose and grow out of it. Their scientific name and species name is Orcaella brevirostris. An Irrawaddy dolphin's heritage belongs to the Oceanic dolphin family. A group of dolphins is called a pod.

Diet

This fascinating specie of dolphins are carnivores meaning they only eat meat. Some things that they eat consist of different types of fish, cephalopods and crustaceans. While feeding, they will sometimes spit out water which is used to herd and confuse fish. This is one of their social behaviours. An adaptation that has happened to the Irrawaddy dolphin is that they team up with fishermen. They do this by, fishermen tapping on the side of their boats which lets the dolphin know that they are ready to fish so they swim in semicircles which herds fish for them and the fishermen.

Habitat

Irrawaddy dolphins are found in coastal areas in South and Southeast Asia. he three rivers they live in are the Ayeyarwady, the Mahakam and the Mekong. Some are even in parts of the Bay of Bengal. They also live in estuaries (large river where the tide meets the stream). The water that the Irrawaddy dolphin lives in is freshwater and brackish (slightly salty). Although their habitat is constantly threatened due to climate change and overfishing.

Behaviour and movements

Irrawaddy dolphins stay in groups of 3 - 6 although, these dolphins are social animals so they will often mix between groups. When Irrawaddy dolphins look around, they will raised their head out of the water and rotate it. They will also move rather slowly when looking. These dolphins make sluggish movements when swimming. Males will often compete for the females attention. When they swim, they will sometimes spy hop, tail slap, body rub, roll to one side waving a flipper and will very rarely leap. The top speed that the Irrawaddy dolphin can reach up to is 25km per hour.

Appearance

This type of dolphin actually have no beak and a rounded forehead. The colour of an Irrawaddy dolphin is dark blue and dark grey although their belly is a pale grey colour. They also have a small fin and a blowhole on the left side on top of their backs. They have 12 - 19 teeth on each side of both jaws. Their weight is 190kgs and their length is 1.5 - 2.8 meters.

Life cycle and life span

This intriguing type of dolphin can live around 30 - 50 years! Irrawaddy dolphin reproduce every three years but they will only have one baby. Their breeding season is December through to June, their calving season is June through to August and their gestation is for nine months. Males sometimes have more than one female mate and this is called Polygynous.

Conclusion

Some interesting facts about an Irrawaddy dolphin is that their predators are sharks and humans and they are related to killer whales. So Irrawaddy dolphins are defiantly a fascinating type of dolphin.

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