Using Digital Tags With Integrated Video and Inertial Sensors to Study Moving Morphology and Associated Function in Large Aquatic Vertebrates

Abstract

The anatomy of large cetaceans has been well documented, mostly through dissection of dead specimens. However, the difficulty of studying the world's largest animals in their natural environment means the functions of anatomical structures must be inferred. Recently, non-invasive tracking devices have been developed that measure body position and orientation, thereby enabling the detailed reconstruction of underwater trajectories. The addition of cameras to the whale-borne tags allows the sensor data to be matched with real-time observations of how whales use their morphological structures, such as flukes, flippers, feeding apparatuses, and blowholes for the physiological functions of locomotion, feeding, and breathing. Here, we describe a new tag design with integrated video and inertial sensors and how it can be used to provide insights to the function of whale anatomy. This technology has the potential to facilitate a wide range of discoveries and comparative studies, but many challenges remain to increase the resolution and applicability of the data.

New views of humpback whale flow dynamics and oral morphology during prey engulfment

“…Unfortunately, some of the most relevant phenomena of whale feeding-indeed, the most pertinent aspects of filtration, including directions, quantities, and timing of intraoral current flow and their relation to intraoral morphology-can be surmised only indirectly given the inability, at present, of placing a tag and recording directly within a whale's mouth. Nonetheless, tag data or calculations from related mathematical modeling have substantially clarified diverse intraoral events (Goldbogen et al , 2015(Goldbogen et al , 2017a. Although video footage from whale-mounted cameras reveals valuable findings directly from foraging animals, often at depths or positions otherwise unavailable to human researchers (Cade et al 2016, Goldbogen et al 2017a, they are somewhat constrained by the limited vantage points they provide from their affixed location on the backs or flanks of whales.…”

“…Nonetheless, tag data or calculations from related mathematical modeling have substantially clarified diverse intraoral events (Goldbogen et al , 2015(Goldbogen et al , 2017a. Although video footage from whale-mounted cameras reveals valuable findings directly from foraging animals, often at depths or positions otherwise unavailable to human researchers (Cade et al 2016, Goldbogen et al 2017a, they are somewhat constrained by the limited vantage points they provide from their affixed location on the backs or flanks of whales. Importantly, these cameras can only provide views within the mouth or show a whole whale interacting with its environment when a second whale serendipitously enters the frame of a tagged whale (Segre et al 2017).…”

“…Nonetheless, tag data or calculations from related mathematical modeling have substantially clarified diverse intraoral events (Goldbogen et al . , , , b ). Although video footage from whale‐mounted cameras reveals valuable findings directly from foraging animals, often at depths or positions otherwise unavailable to human researchers (Cade et al .…”

“…, Goldbogen et al . ), they are somewhat constrained by the limited vantage points they provide from their affixed location on the backs or flanks of whales. Importantly, these cameras can only provide views within the mouth or show a whole whale interacting with its environment when a second whale serendipitously enters the frame of a tagged whale (Segre et al .…”

“…Fortunately, just as digital tags have gained new capabilities while decreasing in size and cost (Goldbogen et al . , ; Goldbogen and Meir ), other recent technological advances have made it easier to capture and analyze video recordings of marine mammal behavior (Nowacek et al . , ; Anderson and Gaston ; Hunt et al .…”