Fujii Jessica A, McLeish Don, Brooks Andrew J, Gaskell John, Van Houtan Kyle S
Monterey Bay Aquarium, Monterey, CA, United States of America.
Hawaiian Hawksbill Conservation, Lahaina, HI, United States of America.
PeerJ. 2018 Mar 28;6:e4565. doi: 10.7717/peerj.4565. eCollection 2018.
The use of limbs for foraging is documented in both marine and terrestrial tetrapods. These behaviors were once believed to be less likely in marine tetrapods due to the physical constraints of body plans adapted to locomotion in a fluid environment. Despite these obstacles, ten distinct types of limb-use while foraging have been previously reported in nine marine tetrapod families. Here, we expand the types of limb-use documented in marine turtles and put it in context with the diversity of marine tetrapods currently known to use limbs for foraging. Additionally, we suggest that such behaviors could have occurred in ancestral turtles, and thus, possibly extend the evolutionary timeline of limb-use behavior in marine tetrapods back approximately 70 million years. Through direct observation and crowd-sourcing, we document the range of behaviors across habitats and prey types, suggesting its widespread occurrence. We argue the presence of these behaviors among marine tetrapods may be limited by limb mobility and evolutionary history, rather than foraging ecology or social learning. These behaviors may also be remnant of ancestral forelimb-use that have been maintained due to a semi-aquatic life history.
海洋和陆地四足动物都有利用四肢觅食的记录。由于身体结构适应在流体环境中运动的物理限制，这些行为曾被认为在海洋四足动物中不太可能出现。尽管存在这些障碍，但此前已在9个海洋四足动物科中报道了10种不同类型的觅食时肢体使用方式。在此，我们扩展了海龟觅食时肢体使用方式的类型，并将其与目前已知利用四肢觅食的海洋四足动物的多样性联系起来。此外，我们认为这种行为可能在海龟祖先中就已出现，因此，可能将海洋四足动物肢体使用行为的进化时间线向前推大约7000万年。通过直接观察和众包，我们记录了不同栖息地和猎物类型的行为范围，表明其广泛存在。我们认为，这些行为在海洋四足动物中的存在可能受到肢体灵活性和进化历史的限制，而非觅食生态或社会学习。这些行为也可能是由于半水生生活史而保留下来的祖先前肢使用方式的残余。
