Common bottlenose dolphins, 'Tursiops truncatus'

Educational value

• The common bottlenose dolphin ('Tursiops truncatus') is a large dolphin that lives in small pods in all the oceans of the world except the polar regions. It is grey with paler undersides and has a distinctive long broad beak.
• Common bottlenose dolphins are high on the marine food chain and eat mostly fish and squid. They are either pelagic (meaning 'open ocean') or coastal, and their diet varies according to the region they live in. They are an opportunistic feeder, which means they take advantage of whatever types of prey are available. Being towards the top of the food chain they are prone to the effects of bioaccumulation of environmental contaminants such as mercury and lead.
• The common bottlenose dolphins in the image belong to a small distinct group of dolphins that live in the fiords of New Zealand. The fiords are cooler than the ocean and have a layer of fresh water above the sea water, which cuts out much sunlight. It is believed there is minimal or no migration of dolphins either in or out of this tight-knit group.
• The dolphins of the fiords have a number of adaptations that help them to survive in their unique habitat. They develop a thick layer of blubber during the cooler months; they use echolocation to find prey in the darker waters; and the birthing of their young is timed to match the warmer months, giving the young the best chance of survival. These dolphins also form very strong bonds, and communicate and cooperate with each other to find food.

Year level

5; 6; 7; 8

Topics Social behaviour (Animals) Marine habitats Dolphins