Supplementary material from "The long-range echo scene of the sperm whale biosonar"

• Main Authors: Tønnesen, Pernille, Oliveira, Cláudia, Johnson, Mark, Madsen, Peter Teglberg
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: The Royal Society 2020
• Subjects: Ecology; FOS Biological sciences; 170299 Cognitive Science not elsewhere classified; FOS Psychology; 60801 Animal Behaviour; Sperm whale
• Online Access: https://dx.doi.org/10.6084/m9.figshare.c.5069688; https://rs.figshare.com/collections/Supplementary_material_from_The_long-range_echo_scene_of_the_sperm_whale_biosonar_/5069688

Sperm whales use their gigantic nose to produce the most powerful sounds in the animal kingdom, presumably to echolocate deep-sea prey at long ranges and possibly to debilitate prey. To test these hypotheses, we deployed sound recording tags (DTAG-4) on the tip of the nose of three sperm whales. One of these recordings yielded over 6000 echo streams from organisms detected up to 144 m ahead of the whale, supporting a long-range prey detection function of the sperm whale biosonar. The whale navigated this complex acoustic scene by maintaining a stable, long-range acoustic gaze suggesting continual resource evaluation. Less than 10% of the echoic organisms recorded by the tag were targeted for capture and only 18% of the buzzes were emitted within the 50 m depth interval of maximum organism encounter rate, demonstrating echo-guided prey selection. Buzzes were initiated greater than 20 m from the prey, showing that sperm whales do not debilitate their prey with sound, but trade echo levels for reduced forward masking and rapid updates on prey location in keeping with the lower manoeuvrability of these large predators. We conclude that the powerful biosonar of sperm whales enables long-range echolocation and selection of prey, but not acoustic debilitation.