Videos, audio clips and information about the killer whale species.
This autumn Gordon Buchanan hitches a ride on a Shetland trawler to follow up reports on some clever killer whales.
Read his High Seas Diary entries on the 2009 Autumnwatch blog.
The killer whale is not a whale but in fact a member of the dolphin family. Some people therefore prefer to call them orcas.
Killer whales have distinctive black and white bodies and dorsal fins that are larger in the males. Individuals can be identified by their dorsal fin shape as well as DNA samples.
They inhabit wide areas of all the world's oceans but many social groups show significant behavioural differences. While some feed on fish, others go for marine mammals including seals and other cetaceans.
Reports of killer whales associating with fishing trawlers date back to the 19th century, but only recently have studies with the populations just off the Shetland Isles begun.
These trawler-feeding pods follow shoals of mackerel from Norway around the west of Scotland and Ireland. It is thought that they recognise the sounds that trawlers make as they haul in their nets.
The whales follow the trawlers picking off mackerel from outside the nets and sucking them in through their teeth. This causes characteristic damage to their teeth, allowing researchers to see which individuals take part in suction feeding.
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UK's largest resident deer species.
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Radio 4 team recording at a Manx bird sanctuary.