[MARMAM] New publication:"Visual and behavioral evidence indicates active hunting by sperm whales"
aokikagari at mac.com
Tue Apr 28 11:48:12 PDT 2015
I'm pleased to announce the publication of
a new paper:
"Visual and behavioral evidence indicates active hunting by sperm whales"
K Aoki, M Amano, T Kubodera, K Mori,R Okamoto, K Sato
Mar Ecol Prog Ser 523:233-241
ABSTRACT: It is hypothesized that sperm whales employ active pursuit strategies for hunting
prey, mainly deep-sea squid at great depths, but no visual evidence has been obtained to confirm
this. We recorded the hunting behavior of sperm whales using animal-borne cameras and
accelerometers simultaneously deployed on 17 whales, and obtained 42.8 h of diving data, including
17 715 images. A statistical comparison indicated no clear effect of light (with or without flashing
white lights from cameras) on diving behavior of tagged whales. Although 98.5% of the still
images were of empty water and uninformative, 5 classes of images with visible material were
identified: (1) suspended material, possibly squid ink (n = 17), (2) unidentified particles (n = 4), (3)
possible animal body parts (n = 2), (4) other sperm whales (n = 221), and (5) the seafloor (n = 8). All
image classes were recorded at deeper depths (mean ± SD = 785 ± 140 m), except Class 4 images,
which were recorded only at depths <339 m, suggesting that tagged whales swam alone while foraging
at great depths. Simultaneous use of speed and image sensors revealed that Class 1 images
were associated with bursts of speed up to approximately twice (3.3 ± 1.0 m s－1, max. 6 m s－1) the
mean swim speed (1.8 ± 0.4 m s－1). These images, likely derived during chasing prey, support the
hypothesis that sperm whales actively hunt to capture prey.
A PDF version of the paper is available online at:
Supplementary movies are here:
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