seals do not need the excess intestine to soak up the nutrients membrane that covers the eyes to protect them from the harsh Similar to harp seals, ribbon seals exhibit a serpentine motion, using their front claws to grip the ice and pulling with alternating fore-flippers while moving the head and hips in a side-to-side motion when they move rapidly on the ice. Adaptation. The lack of a pinna in “earless” seals, like the harp seal, and the presence of a long ear canal partially plugged with wax, may reduce hearing capacity in air. Female foraging efficiency is strongly linked to body mass, which was the sole predictor of residence time in foraging zones (Hassrick et al. Blubber also rounds out the body contours to streamline the seal's body and reduce drag when swimming. This is because they need to be able navigate their ways through large bodies of water. Individuals generally show high philopatry, returning to the same foraging areas during postbreeding and postmolt migrations. Kit M. Kovacs, in Encyclopedia of Marine Mammals (Third Edition), 2018. 2012, Biuw et al. That value became clearer when a plan to allow sea otters to expand their range southward to Santa Barbara, was subjected to a cost-benefit analysis. The value and extent of dedicated non cetacean marine mammal tourism has been estimated in a number of areas. are supported by smooth muscle and cartilage, as well as alveoli diffusion for gases and nutrients. Harp seals, hooded seals, both northern and southern elephant seals, and possibly Weddell seals change their locations in predictable, seasonal patterns that are likely, at least in part, linked to the availability of prey. The fitness of individuals that begin at age 4 is greater than those that begin at age 3 because there is a cost, in terms of reduced survivorship, for those that begin breeding at age 3 (Reiter and Le Boeuf, 1991). Seals molt once a year to get rid of their old skin and have a new skin. penguin. With the advances in biotelemetric tracking technologies (i.e., multisensor satellite-linked tags, including CTD-SRDLs—conductivity, temperature depth Satellite Relay Data Loggers; also see Chapter 10 and Section 14.3.2 of Chapter 14), details of the foraging behavior and foraging habitat(s) of these deep-diving seals have been documented. In some areas where marine mammals are hunted, comparisons have been made between the value of tourism vs hunting. They spend lots of time on land while molting to maintain their body temperature Erich Hoyt, in Encyclopedia of Marine Mammals (Third Edition), 2018. Their sense of smell may also allow harp seals to detect approaching predators when on ice. In years of high harvests, up to 150,000 animals were taken in the North Atlantic. to be proportionally large, and contains a large spherical lens Harp seals also have well-developed beaded whiskers. Nevertheless, these extremely long migrations are not undertaken by all northern elephant seals. The 2008 world totals revealed that nearly 13 million people went whale watching in 119 countries and overseas territories, spending more than USD $2.1 billion (Hoyt, 2001; O’Connor et al., 2009) (Table 1). University of Wisconsin La Crosse. Because adult females remain on the ice to defend their pups against hunters, many adult females were killed. Additionally, jaw sensor detectors and animal-borne cameras have contributed to understanding foraging behavior of these animals (Naito et al. Sea-ice predictions suggest that the breeding habitat of hooded seals will decline dramatically in the decades to come, and the precipitous declines in the abundance of the Northeast Atlantic hooded seal stock in recent decades might be linked to changes already taking place in sea-ice conditions and distribution as well as broader ecosystems shifts. mobile. They conserve oxygen by lowering their heart rate by 90%; only the 2001). return to is normal chemistry. marine waters. Mainland Norway’s whale watching industry offers sperm whales and various dolphins (May–September) and killer, humpback, sperm and fin whales during the low-light winter months; the whale watchers primarily come from other European countries. A seal can spend approximately 15 important to the seals for navigation, their eyes have evolved Han and Shahidi (1995) extracted crude gastric proteinase from harp seal stomach which showed optimum stability at pH 3.0 but was unstable at alkaline pH; however, the extract maintained activities of 70 and 90% at 5 and 25°C, respectively, and was active after ∼40 min at 70°C. Sperm whales exhibit similar patterns of latitudinal segregation by gender in North Pacific foraging areas. Harp seals also have well developed, beaded whiskers, called vibrissae, arranged in horizontal rows on both sides of the snout. Around Monterey, California, sea otters (Enhydra lutris) have become mascots for the region, with a value to tourism in the millions of dollars. Interestingly enough, in order to deal with the intense glare of The principal prey of these elephant seals are mesopelagic squid and fish that spend daylight hours below 400 m and ascend nearer the surface at night, which explains the diel rhythms in the seals’ dive depths. In addition to providing propulsion in water, the flippers serve to regulate heat loss by means of countercurrent heat exchangers. commonly known as capillaries. Inshore and offshore migratory patterns are seen in other species, such as the spotted seals (Phoca largha). Animals from colonies at the southernmost reaches of the species range did not undertake such long northward migrations; a large proportion of seals from these breeding congregations foraged locally, implying plasticity in foraging strategies and possibly prey types (Robinson et al. By attaching various types of “tags” to animals while they occupy their island rookeries, dive behaviors of individual animals can be recorded continuously for many months. Even more remarkably, seals possess good directional hearing both in air and under water. have a longer intestinal tract than an animal with a comparable Hooded seals have been commercially exploited for centuries; usually in conjunction with hunts whose primary target was the more abundant harp seal.