![]() The main food source for sperm whales are medium sized squid (0.5 m and 1–3 kg), of which 70–80% are slow moving, ammoniacal species 4, 5, while the remainder are faster moving squid and fish targeted at meso- and epipelagic depths 6, 7, 8. Sperm whales are mainly teuthophagous predators that spend more than half of their life below 500 meters depth where they target meso- and benthopelagic prey. Today, almost 200 years later, that question is still relevant for the largest tooth-bearing predator on the planet, a major nutrient recycler in the world’s oceans 2 responsible for an annual biomass turnover that has been compared to the combined catches of human fisheries 3. “ It remains, then, to be inquired in what way the sperm whale (Physeter macrocephalus) usually does supply his enormous frame with sufficient food” wrote the whaling surgeon Beale in 1840 1. The high temporal resolution helps to guide motor patterns during occasionally prolonged chases in which prey are eventually subdued with the aid of fast jaw movements and/or buccal suction as indicated by acceleration transients (jerks) near the end of buzzes. Rather, buzzing involves high-frequency, low amplitude clicks well suited to provide high-resolution biosonar updates during the last stages of capture. As a result, received levels at the prey are more than an order of magnitude below levels required for debilitation, precluding acoustic stunning to facilitate prey capture. We show that in the terminal buzz phase, sperm whales reduce inter-click intervals and estimated source levels by 1–2 orders of magnitude. Here we test these hypotheses by using sound and movement recording tags in a fine-scale study of buzz sequences to relate the acoustic behaviour of sperm whales with changes in acceleration in their head region during prey capture attempts. ![]() Several hypotheses have been advanced to propose both active and passive means to acquire prey, including acoustic debilitation of prey with very powerful clicks. However, it remains a conundrum how this bizarrely shaped apex predator catches its prey. The sperm whale carries a hypertrophied nose that generates powerful clicks for long-range echolocation.
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