The irrawaddy dolphin is probably the strangest looking dolphin in the world. It has an appearance which is quite similar to that of a beluga whale, with a bulging forehead and no protruding beak. The dorsal fin is not located in the middle of the dolphin’s back but rather two thirds of the way down. Instead of short pectoral fins it has long flippers. The strange characteristics of the irrawaddy dolphin don’t end there. Its blowhole is u-shaped instead of being circular and is not in the center of the dolphin’s back but is situated off to the left.
They have fewer teeth than most dolphins with the average adult possessing just 24 – 38. Their reduced number of teeth means that their diet is more restricted than that of other dolphins. They only eat small, bony fish. They eat a lot of fish eggs, crustaceans and smaller squid. The lack of protruding beak means that they are able to suck their food into their mouths. They can also squirt powerful streams of water from their mouths which they use to herd fish when hunting in groups.
Irrawaddy dolphins live in a fairly limited geographical area. They live in coastal waters never straying far from the shore and are regularly spotted in estuaries. They can only be seen around the Bay of Bengal and on the coast of Southeast Asia.
They are average-sized, measuring between 7 and 9 feet. They weigh anything from 200 – 440 lb and the males tend to be longer and heavier. The gestation period is quite long at 14 months and female irrawaddy dolphins give birth to just one calf every 2 or 3 years. These dolphins aren’t usually fully weaned until they are 2 years old and the females do not become fertile until they are at least 6 years old.
Irrawaddy dolphins do not tend to play in bow waves like other species as they are relatively slow swimmers, so are limited in the boats which they can chase. They have only been recorded to swim at speeds of 25 km per hour which is much slower than most other dolphin species. If they come across boats on their journeys they tend to dive rather than interact with the humans on board. They are generally less sociable animals and are usually found in pairs or threes. They don’t tend to live in groups larger than 5 but they have occasionally been spotted in pods made up of 25 individuals.