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For anyone planning to embark on a whale watching cruise, the incredible documentary series Blue Planet II, hosted by veteran naturalist Sir David Attenborough, makes for compelling viewing. It features many of the cetaceans that may be encountered on a whale watching cruise, including Humpback, Killer, pilot and Sperm Whales. The World's Largest Whale Found in nearly all the world's oceans, the Sperm Whale is one of the most commonly sighted species on whale watching tours. From the Azores or the Maldives, to Baja California or Norway's spectacular Lofoten Islands, the opportunities to catch sightings of the largest toothed predator on the planet are diverse and exciting. A Family Affair Using hi-tech suction cap cameras attached to the bodies of the animals themselves, Blue Planet II featured incredible footage of a pod of Sperm Whales hunting for squid hundreds of metres down, which revealed some fascinating feeding behaviours. The aim of the Blue Planet II team was to capture intimate footage of a family to understand how they use their complex social networks for hunting and survival. Because they spend a great deal of their time at extreme depths, filming them for sustained periods was a huge challenge. Enter the D-tag camera tags, which were attached to multiple members of the pod. While there has been previous footage of a Sperm Whale diving, a complete dive cycle had never been captured before the astonishing Blue Planet II sequences. Hunting Behaviours Requiring up to 900kg of food a day, Sperm Whales use a sophisticated echolocation technique to find prey by emitting a series of clicks, which are, in fact, the loudest noise of any animal on the planet. Their diet consists mainly of squid, octopuses, rays and smaller fish. When hunting small fish, the pod works co-operatively to drive the feeder fish into a tight ball at the surface of the water, which they then consume in huge mouthfuls. Their preferred food, however, is the giant squid, and they are capable of diving as deep as two kilometres on the hunt – although more commonly they dive between 300-1200m. It's believed that adults can hold their breath for anything up to two hours, with an average dive lasting around an hour. One interesting thing that the Blue Planet II footage revealed is the inability of calves to dive with the rest of the pod while hunting squid. It appeared that, while diving in unison, the members of the pod were trying to teach the calves to dive but, unable to keep up, the calves eventually returned to wait near the surface of the water until their mothers returned from the deep with their cache of giant squid. Even then, it appeared that the adults used pieces of the squid to teach them techniques for catching their own. The whale is a ruthless predator of the squid, but as yet it is not yet known how they actually kill them. One theory is that they use powerful ultrasound vibrations to render the squid unconscious before scooping them up in their giant toothed jaws. See Them for Yourself A whale watching cruise offers a rare and privileged glimpse into the life of these magnificent creatures as they come to the surface of the ocean, but Sir David Attenborough and Blue Planet II remind us there is so much more that we don't yet know about their secret deep water existence. Author Plate Marissa Ellis-Snow is a freelance nature writer with a special interest in whale watching. As a passionate lover of marine wildlife, Marissa chooses the expert-led whale watching cruise itneraries organised by Naturetrek, which have brought her unforgettable sightings of a wide range of wildlife in some of the most spectacular regions on Earth.
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