Irrawaddy Dolphin

The Irrawaddy Dolphin inhabits shallow coastal waters, estuaries, and large river systems from the Bay of Bengal through Southeast Asia to New Guinea and the Philippines. Typically found in small loose groups of two to ten individuals, this dolphin forages near the surface and in mid-depth zones using slow, rolling movements. It communicates through clicks, creaks, and buzzes, relying on echolocation to navigate turbid waters. Dolphins may engage in cooperative fishing with local communities, herding fish into nets in exchange for bycatch. Although generally non-migratory, some subpopulations exhibit seasonal movements linked to water level changes. Activity peaks at dawn and dusk, with rest periods in deeper river channels or sheltered coastal areas. These dolphins are shy of boats but may spyhop or breach when curious or disturbed, demonstrating both cautious and playful behaviors.

The Irrawaddy Dolphin has a carnivorous diet that includes fish, crustaceans, and cephalopods. It employs suction feeding, drawing prey into its mouth by rapidly expanding its throat pouch. Individuals often forage alone or in small groups, circling shoals of fish before sucking them in. In river habitats, they consume freshwater fish species, while coastal groups target small marine fish and shrimp. Seasonal variations in prey abundance cause dolphins to adjust foraging depth and location. Nutrient intake from protein-rich fish and crustaceans supports energy needs for thermoregulation in varying water temperatures. Calves initially rely on maternal milk for up to two years before transitioning to solid prey. This balanced diet enables Irrawaddy Dolphins to thrive in both brackish and freshwater ecosystems.

Mating occurs primarily between December and June, with individuals engaging in brief courtship where pairs intertwine their bodies and copulate for approximately forty seconds. Calving often follows every two to three years after a gestation of fourteen months. Females reach sexual maturity at seven to nine years of age. Male involvement after birth is limited, and the mother alone cares for the calf in hidden river or coastal areas until weaning.

Global populations number over seven thousand individuals, yet distribution is fragmented into discrete coastal and riverine subpopulations across South and Southeast Asia. Some river systems harbor fewer than one hundred dolphins, and subpopulations continue to decline due to bycatch, habitat degradation, and water pollution. Conservation efforts include protected areas, fishing restrictions, habitat restoration, and community-based monitoring to stabilize and recover populations under Endangered species status.