Question

How does military sonar affect whale behavior?

• How do whales use sound to communicate with one another?

• What are the benefits of using sound to communicate underwater? What are the costs?

Answer 1

1. Sonar does affect whales, military report confirms.Animals stopped vocalizing and foraging for foos during marine exercises.But military - sponsored   tests now suggest that low levels of sonar , which do not cause direct damage to whales , could still cause harm by triggering behavioural changes.Across the course of the exercise, the number of whale recordings dropped from over 200 to less than 50.''beaked whale species appear to cease vocalising and foraging for food in the area around active sonar transmissions'', conclude the report.                It notes'' Since these animals feed at depth, this could have the effect of preventing a beaked whale from feeding over the course of the trial and could lead to second or third order effects on the animal and population as a whole.

2. Whales are very social creatures that travel in groups called ''pods''. They use a variety of noises to communicate and socialize with each other.The three main types of sounds made by whales are clicks,whistles,and pulsed calls.

    Clicks are believed to be for navigation and identifying physical surroundings.When the sound waves bounce off   of an object, they return to the whale, allowing the whale to identify the shape of the object.Clicks have also been observed during social interactions.

Whales also use their tails and fins to make loud slapping noises on the surface of the water to communicate nonverbally.The sound can be heard for hundreds of meters below the surface and may be a warning sign of aggression or a toolto scare schools of fish together, making them an easier meal.

3. Some marine mammals also use sound for the maintenance of group structure.Similar to sonar systems on ships, some whales use sound to detect, localize, and characterize objects.Some whales and dolphins use echoocation to locate food.They send out pulsed sounds that are reflected back when they strike a target.Echolocation is an effective way to locate prey and also helps whales and dolphins analyze their environment.