BBC Learning English
Words in the News
4nd March 2011
Orcas have cunning hunting strategy
Orcas are usually highly communicative killer whales, but researchers from St Andrews
University have found out that they hunt in complete silence to avoid being overheard by their
prey. Victoria Gill reports.
Killer whales whistle to talk to each other and click to find their way around. It's the echoes
from these clicks that help the animals to map their surroundings and to pinpoint the
location of their next meal.
But while one type of killer whale eats fish, the other hunts marine mammals, including seals
and porpoises. A shoal of salmon can't hear the clicking of an approaching killer whale, but
the mammals, with their highly sensitive underwater hearing, can.
The researchers used underwater microphones to listen to killer whales hunting seals off the
coast of Alaska. They found that the animals fell completely silent when they were hunting.
But, somehow, they still managed to organise themselves into groups - often spreading out
up to a mile apart, before coming back together and calling loudly to each other while they
shared their catch.
The scientists now hope to attach satellite trackers to individual killer whales, to find out more
about this stealthy behaviour.
Victoria Gill, BBC News
Words in the News © British Broadcasting Corporation 2011
Page 1 of 2
bbclearningenglish.com
Vocabulary and definitions
whistle make a loud, high sound
echoes sounds which can be heard to repeat after the original
noise has stopped
surroundings the area around a person or animal
to pinpoint to search and find
mammals certain types of warm-blooded animals (e.g. humans, dogs)
shoal large group of fish, swimming together
fell silent became completely quiet
spreading out separating to cover a wider area
catch food caught while hunting
stealthy moving about in a careful way, trying not to be seen
More on this story: http://www.bbc.co.uk/nature/life/Killer_whale
Read and listen to the story and the vocabulary online:
http://www.bbc.co.uk/worldservice/learningenglish/language/wordsinthenews/2011/03/110304_witn_killer_whale_page.shtml
Words in the News © British Broadcasting Corporation 2011
Page 2 of 2
bbclearningenglish.com