Indo-Pacific Bottlenose Dolphin

The Indo-Pacific bottlenose dolphin (Tursiops aduncus) is a fascinating marine mammal known for its social behavior and wide-ranging habitat. These dolphins generally reach an average length of 2.6 meters (8.5 feet) and weigh up to 230 kilograms (510 pounds). They inhabit the coastal waters of regions like 🇮🇳 India, northern 🇦🇺 Australia, the South China Sea, the 🌊 Red Sea, and the eastern coast of Africa.

Distinguishing features of the Indo-Pacific bottlenose dolphin include a dark grey back with a lighter grey or nearly white belly, often marked with grey spots. They have a more slender build and longer rostrum compared to their close relative, the common bottlenose dolphin. Their dental structure also differs, with 23 to 29 teeth on each side of each jaw, compared to 21 to 24 in the common species.

Indo-Pacific bottlenose dolphins have a varied diet, primarily consisting of fish and cephalopods like squid. Research conducted off Zanzibar showed that fish made up 87% of their diet, while cephalopods accounted for 13%.

These dolphins are social creatures, typically living in groups ranging from five to 15 individuals, although larger groups can form. Their social structure sometimes allows them to associate with other dolphin species. Reproduction occurs year-round in certain areas, with peak seasons in spring and summer. The gestation period lasts about 12 months, with calves measuring between 0.84 and 1.5 meters (2.8 and 4.9 feet) at birth and weighing between 9 and 21 kilograms (20 and 46 pounds).

Interestingly, dolphins in Shark Bay, 🇦🇺 Australia, have demonstrated unique tool-using behavior by utilizing marine sponges to uncover prey, a behavior known as "sponging." Dolphins have also been observed rubbing against corals and sponges, likely utilizing their beneficial properties to maintain skin health.

Indo-Pacific bottlenose dolphins face various conservation concerns, particularly regarding capture and captivity, which can impact wild populations and ecosystem balance. They are currently listed as "near threatened" by the International Union for Conservation of Nature (IUCN). Human activities such as increased maritime traffic for wildlife viewing, including whale watching, have been shown to alter their natural behaviors. Studies have revealed that these dolphins modify their whistle frequencies and behaviors in response to ambient noise and the presence of vessels, demonstrating their adaptability, though the long-term impact on the population is still uncertain. These playful and intelligent dolphins can live for over 40 years, though they are occasionally predated by sharks in some regions.