Biology:

Physiology

(Image credit: © Andrew Reding 2010)

Homeostasis

Sea otters are endotherms (meaning they produce their own body heat rather than relying on external heat to maintain homeostasis), primarily regulating temperature through their dense fur. They groom their fur to trap air and this grooming is a large part of their daily activity. Since water has a high thermal conductivity, sea otters have a metabolic rate almost three times that of land mammals. (Zellmer et al., 2021) This high metabolic rate necessitates high quantities of food intake to acquire the necessary intake of calories, nitrogen, electrolytes, and water. Their large, lobulate kidneys are suspected to aid in producing large volumes of urine to filter out toxins in their diet (Strobel et al., 2020).

(Image credit: © Alan Wolf, 2007)

Sensory

Sea otters can hear underwater but their hearing is mainly adapted for air. They discriminate smells, especially pheromones that influence sexual behavior. Their taste buds and keen sense of smell are important tools in avoiding paralytic shellfish poisoning as some of their main food sources have the chance of containing high levels of toxins (Kvitek et al., 1991). They have adapted amphibious eyes with small pupils and retinas dominated by rods, similar to carnivores such as cats and ferrets. Their eyes have a thick outer nuclear layers like many amphibious predators, with a wide pupil size range for the vast differences of light on the ocean floor versus out in broad daylight (Strobel et al., 2020).

(Image credit: © Travis 2008)

Musculoskeletal

Their skeletons are adapted for locomotion through water. Their spines are flexible, and their short limbs reduce drag in the water. They use undulation with pelvic paddling to swim while completely submerged (Zellmer et al., 2021). Their hearts are normally-sized compared to pinnipeds and other marine mammals, making up on average between 0.66 and 0.72% of total body weight (Morejohn, 1975).

(Image credit: © McGann 2011)

Respiration

Sea otters have a large lung capacity. While their respiration is similar to other mammals, their large lung capacity keeps them buoyant while sleeping and helps with their swimming (Zellmer et al., 2021). However, this buoyancy has its disadvantages while foraging the seafloor for prey, making hunting quite energy-costly (Thometz et al., 2015).

References:

Zellmer, N. T., Timm-Davis, L. L., & Davis, R. W. (2021). Sea otter behavior: Morphologic, physiologic, and sensory adaptations. Ethology and Behavioral Ecology of Sea Otters and Polar Bears, 23–55. https://doi.org/10.1007/978-3-030-66796-2_3

Kvitek, R. G., DeGunge, A. R., & Beitler, M. K. (1991). Paralytic shellfish poisoning toxins mediate feeding behavior of sea otters. Limnology and Oceanography, 36(2), 393–404. https://doi.org/10.4319/lo.1991.36.2.0393

Reding, A. (2010). Sea otters. Flickr. Retrieved December 18, 2022, from https://www.flickr.com/photos/seaotter/15909543933/in/album-72157631763622164/

Wolf, A. (2007). Sea otter peek-a-boo. Flickr. Retrieved December 18, 2022, from https://www.flickr.com/photos/alumroot/734669148/in/photolist-27Vnxs-2jNtABa-2ha9stx-2hCPHka-wMxtyZ-XZmUYg-xJq6A6-oYMjFU-x6Rhxi-6teqjy-pfZASV-wNSJDw-6pkxiZ-6dL3Pt-dLuJDj-wPcrPQ-wPer2f-y7HjkJ-ovRCes-jboJpK-wj8Yh1-rYP1K-TQu4rd-re1Hc-x1zLXu-8rHAWL-xsRTzU-zP7uJZ-84aaNo-sM2sQg-ovRBAo-oepvrx-xDHLNv-xndzye-f4h589-xq9TiL-x1zwsQ-8QeYL7-syBKz-xjznNg-6YFMtz-61PGrQ-6u9Pqy-wKpA9q-dMWPZ3-xVdzq-6BZvao-84aaqs-84a9Sw-84aaxj.

Travis. (2008). Sea otter. Flickr. Retrieved December 18, 2022, from https://www.flickr.com/photos/baggis/2558236032/in/photolist-4U4Cnu-4U4CrN-q1W7Qd-6rEDYA-4U4Cwy-oeSm1N-71pGg6-oviNxj-xXRTFt-w9Wn3Z-wPer2f-6geWCx-wjuMkt-qij2RB-wPEYgQ-wJfnvu-2hoa5xn-xndzye-xDnx4g-wtecZ7-x99DRw-xb5x81-wYe3op-9zsA1f.

McGann, P. (2011). Sea otter. Flickr. Retrieved December 18, 2022, from https://www.flickr.com/photos/pattymc/6296348274/in/photolist-aAoqYS-5j52vC.

Strobel, S. M. K., Moore, B. A., Freeman, K. S., Murray, M. J., & Reichmuth, C. (2020). Adaptations for amphibious vision in Sea Otters (enhydra lutris): Structural and functional observations. Journal of Comparative Physiology A, 206(5), 767–782. https://doi.org/10.1007/s00359-020-01436-4

Morejohn, G. V. (1975). Post mortem studies of sea otters, Enhydra Lutris L., in California. California Department of Fish and Games.

Thometz, N. M., Murray, M. J., & Williams, T. M. (2015). Ontogeny of oxygen storage capacity and diving ability in the Southern Sea Otter (Enhydra lutris nereis): Costs and benefits of large lungs. Physiological and Biochemical Zoology, 88(3), 311–327. https://doi.org/10.1086/681019

Page updated

Google Sites

Report abuse