They use sonar in order to find other species and food.
The authorities yesterday were using sonar to pinpoint the location.
A second machine uses sonar to identify objects at the sea bottom.
Part of the exercise was being used to measure ice thickness by using sonar.
Except watch and proceed cautiously in the same direction, using passive sonar for the moment.
They have developed gills and can sense their surroundings using sonar.
Also, by using sonar, they can place the bait according to where they think the fish are.
Using passive sonar was the normal routine in such a case.
There is another dark world where animals use sonar to find their way around.
That has long meant using sonar to "see" the terrain under the boat.