SUMMARY The feeding kinematics of dwarf and pygmy sperm whales (Kogia simaand K. breviceps) and bottlenose dolphins Tursiops truncatuswere characterized and compared incorporating the Ram-Suction Index (RSI). Mean RSI data support a suction feeding strategy for Kogia(-0.67±0.29; mean ± s.d.) and a ram feeding strategy for Tursiops (0.94±0.11; mean ± s.d.). Tursiops displayed two ram-based feeding behaviours: open gape approach, where gape was at least 50% of maximum in the first video field, and closed gape approach, where gape increased near food items. Four feeding phases were identified in both odontocetes: preparatory, jaw opening, gular depression and jaw closing. The mean Kogia feeding cycle duration(470±139 ms) was significantly shorter (P<0.003) than all Tursiops groups (pooled: 863±337 ms; open gape approach:1211±207 ms; closed gape approach: 662±207 ms). Kogiamean maximum gape angle (39.8±18.9°), mean maximum opening and closing gape angle velocities (293±261 deg. s-1 and 223±121 deg. s-1, respectively) were significantly greater(P<0.005) than pooled Tursiops mean maximum gape angle(24.8±6.6°), mean maximum opening and closing gape angle velocities(84±56 deg. s-1 and 120±54 deg. s-1,respectively). Negative Kogia RSI values were correlated with increasing maximum gular depression and retraction, wide gape angle, and rapid opening gape angle velocity. Kinematic data support functional hypotheses that odontocetes generate suction by rapid depression of the hyoid and tongue.

The development of advanced technologies to enhance conservation science often outpaces the abilities of wildlife managers to assess and ensure such new tools are safely used in proximity to wild animals. Recently, unmanned aerial systems (UAS) have become more accessible to civilian operators and are quickly being integrated into existing research paradigms to replace manned aircraft. Several federal statutes require scientists to obtain research permits to closely approach protected species of wildlife, such as marine mammals, but the lack of available information on the effects of UAS operations on these species has made it difficult to evaluate and mitigate potential impacts. Here, we present a synthesis of the current state of scientific understanding of the impacts of UAS usage near marine mammals. We also identify key data gaps that are currently limiting the ability of marine resource managers to develop appropriate guidelines, policies, or regulations for safe and responsible operation of UAS near marine mammals. We recommend researchers prioritize collecting, analyzing, and disseminating data on marine mammal responses to UAS when using the devices to better inform the scientific community, regulators, and hobbyists about potential effects and assist with the development of appropriate mitigation measures.

Kogia breviceps (de Blainville, 1838) is a cetacean commonly called the pygmy sperm whale. A diminutive relative of the sperm whale and difficult to identify in the field, it is 1 of only 2 members of the genus Kogia. It is endemic to offshore waters of the Pacific, Atlantic, and Indian oceans in temperate and tropical regions. It is considered solitary and deep-diving in pursuit of cephalopod prey. Abundance is poorly known, although it is protected under U.S. federal and international law. No specimens have ever been maintained permanently in captivity, and, temporary holding of stranded individuals has rarely been nonlethal.

The function of the hyolingual complex in three odontocete species was investigated to compare adaptations of divergent feeding strategies, suction and ram feeding. Pygmy and dwarf sperm whales, members of the genus Kogia (or kogiids), are known to be strong suction feeders. We tested the hypotheses that kogiids would have a larger, more robust hyolingual complex, and that hyolingual muscles would have a greater maximum theoretical muscle tension compared with ram-based feeders such as bottlenose dolphins ( Tursiops truncatus ). A robustness index and surface area was calculated for bony hyoid elements in kogiids and bottlenose dolphins. The anatomy, muscle architecture, pinnation, two-dimensional angle of attachment and maximum theoretical muscle tension were measured in each hyolingual muscle. A functional model incorporating vector analyses of hyolingual musculature was created for kogiids and bottlenose dolphins to assess differences in function of their hyolingual complexes. Kogiid hyoid surface areas were significantly greater ( P = 0.01) than in bottlenose dolphins. Most maximum theoretical muscle tensions of hyolingual complexes were not significantly different within or between species. The data suggest that associated orofacial and tongue morphology, particularly the relationship of hyoid shape and tongue retractor muscles, greatly influences suction capability in odontocetes. Kogiids demonstrated adaptations that occlude lateral gape, including a novel vertical ridge on each side of the mandible, and a shortened mandible that is capable of a large gape, and gape angle. These adaptations presumably assist in maintaining negative intraoral pressure generated by the depression and retraction of the relatively short and wide kogiid tongue. The tongues of kogiids should be capable of generating greater intraoral volume changes compared with the long, narrow tongue of bottlenose dolphins.