Pilot Whale are known to swim very fast underwater. They actively pursue squid, and their unique hunting strategy is very successful.
Some Whale Diving and Hunting Strategies
Sperm Whales dive passively – they lift their heavy flukes far out of the water and probably adjust their buoyancy so that they are pushed very deep, without having to actually use up energy swimming down. Conserving energy like this means that they can spend a long time (up to 2 hours) locating giant squid and catching them. Exactly how sperm whales kill the squid is still a matter of speculation, but it has been suggested that they might be able to generate sufficiently loud bursts of sound to stun them. If this is true then their hunting also conserves energy.
Pilot Whales have evolved completely different techniques for hunting similar, if somewhat smaller, squid. They also lift their flukes out of the water to help start the dive, but after that they swim down very fast. Once they have found squid they simply run them down. This highly energetic behaviour means that Pilot Whales cannot dive as deep as Sperm Whales, nor stay under for as long – but the strategy must work well because Pilot Whales are very successful!
Echo-location and Communication
The large ‘melon’ on the head of the pilot whale is very similar to that of the Beluga, and it is certainly related to precise echo-location. Belugas are probably concerned with finding holes in the ice as much as locating prey, but the tropical Short-finned (or Pacific) Pilot Whale must use it entirely for hunting. Belugas are very social and ‘chatty’, and similarly Pilot Whales live in large pods and seem to communicate with one-another – both on the surface and when underwater. Pilot Whales have been recorded hunting co-operatively (as have Humpback Whales), and this implies detailed ‘conversations’ about strategy.
Pilot Whale Strandings
Exactly why groups of Pilot Whales get stranded on the shore so frequently is not known. It might be that something confuses their navigational systems, or maybe they become over-enthusiastic chasing prey towards shallow water? Certainly when one is stuck others from the pod seem to come ashore to help, adding to the numbers that will die. In the past this behaviour was exploited by whalers who used to ‘drive’ them towards the land and then kill them on the beach, and this is still done today on the Faroe Islands. In other parts of the world they are also caught by harpooning, and many become entangled in fishing nets. In spite of this Pilot Whales are still very numerous worldwide.
