1. High-powered outboard motors were considered to be one of the major threats to the survival of the Beluga whales.

A. With these, hunters could approach Belugas within hunting range and profit from its inner skin and blubber.

B. To escape an approaching motor, Belugas have learned to dive to the ocean bottom and stay there for up to 20 minutes, by which time the confused predator has left.

C. Today, however, even with much more powerful engines, it is difficult to come close, because the whales seem to disappear suddenly just when you thought you had them in your sights.

D. When the first outboard engines arrived in the early 1930s, one came across 4 and 8 HP motors.

6. Belugas seem to have used their well-known sensitivity to noise to evolve an ‘avoidance' strategy to outsmart hunters and their powerful technologies.