What Family Does the Sperm Whale Belong to

Sperm Whale

Hal Whitehead , in Encyclopedia of Marine Mammals (Tertiary Edition), 2018

I Characteristics and Taxonomy

In 1758, Linnaeus described four sperm whales in the genus Physeter. Information technology soon became clear that all refer to the aforementioned species, simply at that place has been a long, and sometimes contentious, argue equally to whether Physeter catodon or Physeter macrocephalus has precedence. Currently, well-nigh, but not all, government prefer P. macrocephalus.

The common name, "sperm whale," seems to accept resulted from whalers misinterpreting the function of the spermaceti oil found in the massive brow of the whale, or considering cooled spermaceti has some physical resemblance to mammalian sperm.

The closest living relatives of the sperm whale are the much smaller dwarf and pygmy sperm whales (Kogia breviceps and Kogia sima). Sperm whales seem to have separated from other odontocetes early in mod cetacean evolution, almost xx–30 million years ago. Run across Sperm and Beaked Whales, Development for more information.

Sperm whales are the largest of the odontocetes (Fig. ane), and the near sexually dimorphic cetaceans in body length and weight. While adult females achieve about eleven k in length and 15 t, a physically mature male is approximately 16 yard and 45 t (Rice, 1989).

The near distinctive feature of the sperm whale is a massive nasal complex (Fig. 2; Ellis, 1980), i quarter to one-third of the length of the brute, situated above the lower jaw and in front of the skull (Cranford, 1999). It principally contains the spermaceti organ, which is enclosed in a muscular "instance" (Fig. two). This is a roughly ellipsoidal shaped structure made of spongy tissue filled with spermaceti oil and divisional at both ends by air sacs. Between the spermaceti organ and the upper jaws is the "junk," a complex arrangement of spermaceti oil and connective tissue. Spermaceti oil, which has the properties of a wax, differs chemically from the oils institute in the "melons" of most other odontocetes.

There is considerable asymmetry in the parts of the skull and air passages that surround the spermaceti organ. This is externally manifested nigh clearly past a blow which is pointed forwards and to the left from the tip of the snout. Compared with the blows of similarly sized baleen whales, the blow of a sperm whale is comparatively weak, depression, and hard to meet.

Backside the sperm whales skull lies a brain, which, together with that of the killer whale (Orcinus orca), is the largest brain of any animal (mean of 7.8 kg in mature male person sperm whales) (Ridgway and Hanson, 2014). However, as a proportion of body size, the sperm whale's brain is not remarkable, and we have no directly data on the sperm whale'southward cognitive abilities, although its complex social organization is consonant with those found in other cognitively advanced mammals.

The sperm whale has 20–26 large conical teeth in each rod-like lower jaw. These teeth do not seem to be necessary for feeding, equally they practice not erupt until near puberty, and well-nourished sperm whales have been caught that lack teeth, or even lower jaws. The teeth in the upper jaw seem to exist vestigial and rarely erupt.

Large corrugations cover most of the body backside the center, just the surface of the caput and the flukes are smooth. The majority of the body is dark gray in most sperm whales, but there is oftentimes a bright white lining to the mouth and sometimes white patches on the abdomen. The occasional sperm whale has larger white patches, peculiarly in mature males, around the head. The flippers are relatively small and paddle shaped, and the flukes are adequately apartment and triangular shaped. The dorsal fin is low, thick, and usually rounded. Especially in mature females, it may be topped past a white or yellowish rough callus. The dorsal ridge, behind the dorsal fin, consists of a series of large crenulations.

Read full chapter

URL:

https://world wide web.sciencedirect.com/scientific discipline/article/pii/B9780128043271002429

Acoustic Scattering past Marine Organisms*

M.G. Foote , in Encyclopedia of Bounding main Sciences (Second Edition), 2001

Marine Mammals

A few measurements have been reported on the target strength of the sperm whale ( Physeter catodon) and the humpback whale (Megaptera novaeangliae) in situ. Measurements have been made of the Atlantic bottlenose dolphin (Tursiops truncatus) in captivity. Measurements made on a 2.2 one thousand long 126 kg female dolphin in broadside attribute at the surface revealed a hateful target strength that decreased from about −10 dB at the everyman measurement frequency of 23 kHz to most −24 dB at 45 kHz, ascent to about −20 dB at 65 kHz, then falling to −25 dB at eighty kHz. The observed degree of variability about these nominal values due to repeated insonification was 4–11 dB to within the showtime standard deviation to either side.

Read full affiliate

URL:

https://www.sciencedirect.com/science/article/pii/B9780123744739003118

Sperm Whales, Evolution

Guram A. Mchedlidze , in Encyclopedia of Marine Mammals (Second Edition), 2009

II Kogiidae

One genus with two modem species constitutes the Kogiidae (Kogia brevieeps and Grand. sima). Kogia is similar to Physeter but the trunk of Kogia is much smaller (body length approximately four m) and the head is smaller (one-6th to one-eighth of the body). The spermaceti organ is smaller than in Physeter, the blowhole more posterior, and the rostrum shorter. Proportions of the caput in Physeter embryos are similar to those of adult Kogia. This suggests that these cetaceans are closely related and that Physeter has a more derived facial morphology.

Kogiids are poorly represented in the fossil record, and most specimens are incomplete, although some localities have yielded good material. The genus Kogiopsis is known from a unmarried mandible, and fragmentary skulls are known for Miocene Scaphokogia and Pliocene Praekogia. Another tendency in the evolution of kogiids is the reduction of dental enamel. This trend started in the Miocene. In modem Kogia some enamel covers the tips of the teeth, whereas Miocene kogiids lack all enamel.

Phylogenetically, Scaphokogia is a basal branch of kogiids, retaining primitive morphologies of rostrum, premaxillae, and intermaxillary groove. It is, nonetheless, more than derived than other kogiids in having a well-developed supracranial basin. Scaphokogia may represent an early, specialized branch of kogiids, the subfamily Scaphokogiidae. These went extinct most the end of the Miocene. Praekogia is closely related to Kogia in that both the nasal passages are anterior due to poorly adult telescoping. The new genus Aprixokogia from the late Tertiary of North Carolina is known from a well-preserved skull (Whitmore and Kaltenback, 2008).

Read total chapter

URL:

https://world wide web.sciencedirect.com/science/commodity/pii/B9780123735539002492

Anatomy of the Viscera

Stefan Huggenberger , ... Bruno Cozzi , in Atlas of the Anatomy of Dolphins and Whales, 2019

The images of the viscera (heart, lungs, liver, stomach complex) of the Cuvier'due south beaked whale Ziphius cavirostris, the sperm whale Physeter microcephalus, and the fin whale Balaenoptera physalus are based on actual dissections and photographic documentation. All the drawings follow the same style of those prepared for Beefcake of Dolphins: Insights into Body Structure and Office that represent the bottlenose dolphin Tursiops truncatus (hither reprinted in larger format). The fin whale is the but species seen from the right, because the topography of the organ was fully available for that side, simply only approximate from the left side.

Read full chapter

URL:

https://www.sciencedirect.com/science/article/pii/B9780128024461000060

Sperm and Beaked Whales, Evolution

Olivier Lambert , ... Christian de Muizon , in Encyclopedia of Marine Mammals (Tertiary Edition), 2018

I Sperm Whales, Fossil Record, and Phylogeny

The superfamily Physeteroidea is fabricated of three groups: the paraphyletic stem Physeteroidea and the families Kogiidae and Physeteridae. Fossil and extant sperm whales are all characterized by: (1) the presence of a vast supracranial basin, housing in mod species the spermaceti organ and adjoining soft tissue elements, (2) highly asymmetrical bony nares and surrounding facial bones, and (3) relatively enlarged dental roots (Fig. 1). In add-on, Kogia and Physeter differ from all other extant odontocetes in separating the right and left soft tissue nasal passages. The earliest fossil physeteroid originates from the Late Oligocene of Caucasus (Ferecetotherium; Mchedlidze, 1976). However, the affinities of this fragmentarily known taxon should be reinvestigated in the calorie-free of more complete specimens.

Stem physeteroids retain a functional upper dentition, with enamel-covered teeth, and their torso length ranges from about four m (Acrophyseter, from Peru) to mayhap up to 17 one thousand (the behemothic Livyatan, too from Republic of peru; Fig. 2; e.1000., Lambert et al., 2017). Most stem sperm whales were constitute in Miocene deposits, with several taxa based on relatively consummate skeletons.

The family Kogiidae is a well-defined clade, with most species beingness characterized by a relatively small size, a curt snout, the presence of a sagittal crest in the supracranial basin, and the loss of the two nasals. A high level of cranial morphological disparity is observed within the group, from the oldest, presumably late early to middle Miocene kogiids to the Pliocene and extant species (Velez-Juarbe et al., 2015); with its broader supracranial bowl and longer and thicker rostrum, the late Miocene Scaphokogia is even placed in its own subfamily Scaphokogiinae.

The content of the family Physeteridae is more debated; several presumed physeterids (e.g., the Miocene Orycterocetus) were occasionally considered as stem physeteroids. As a consequence, cardinal morphological characters of the family unit are for now not available, although a trend in the reduction of the upper dentition, coupled with a loss of dental enamel, and an increase in body size (with the Miocene Aulophyseter and the extant Physeter as the largest taxa) are observed within the family unit. The oldest currently recognized physeterids date from the early Miocene.

Read full chapter

URL:

https://www.sciencedirect.com/science/article/pii/B9780128043271002417

Marine Ecosystems of Andaman and Nicobar Islands – Species Abundance and Distribution

Nambali Valsalan Vinithkumar , ... Nambali Valsalan Sujathkumar , in Biodiversity and Climate Alter Accommodation in Tropical Islands, 2008

iv.10 Marine Mammals Biodiversity and Distribution

The marine mammals in Republic of india are represented by 25 species (Kumaran, 2002) including, sea moo-cow, dolphins and whales. All the species are endangered and are protected nether the Indian Wildlife (Protection) Act 1972 (Rajagopalan and Menon, 2003). The studies on marine mammals in India are very scanty due to difficulty in accessing offshore h2o based enquiry back up. Kannan and Rajagopalan (2013) reported about 21 siting of marine mammals fabricated during 2005 in N, Middle, South and Fiddling Andaman equally well as from Nicobar Islands. The species observed include Physeter microcephalus (sperm whale), Tursiops sp., (dolphin) and Stenella longirostris (spinner dolphin).

The highly endangered marine mammal species in India is Dugong dugon which is unremarkably called as Sea Cow belongs to the Gild Sirenia. This is the merely herbivorous mammal lives exclusively in the seas of tropical and subtropical waters of Indo-Pacific region including India.They are found along the coast of Gulf of Mannar, Palk Bay, Gulf of Kutch and Andaman and Nicobar Islands, numbering about 200 individuals (Sivakumar, 2013). These animals are classified on the global Red List of IUCN as 'Vulnerable to extinction' and also included in the Appendix I of the Convention on International Merchandise in Endangered Species of Wild fauna and Flora. Sivakumar (2013) too reported that to conserve and manage the declining population in India, a Chore Forcefulness for Conservation of Dugong in Bharat was constituted past the Authorities of India to formulate the conservation action plan for Dugong. In Andaman and Nicobar Islands they are found in trophy and around the coasts of Interview Isle, reported from Ritchie's Archipelago, Due north reef. Picayune Andaman, Camorta, Little Nicobar (Das, 1996). The population of Dugong estimated betwixt 131 and 254 individuals using an interview based survey by the GEER foundation during 2009 and in that the number arrived for Andaman and Nicobar Islands were very small as 44–81 individuals (Pandey et al., 2010).

Read full chapter

URL:

https://www.sciencedirect.com/science/commodity/pii/B9780128130643000089

Development past Loss

Nelson R. Cabej , in Epigenetic Principles of Development, 2012

Loss/Reduction of Limbs in Aquatic Mammals

Paleontological evidence shows that the ancestral forms of modern cetaceans, such as Pakicetus inachus of Early Eocene (ca. 58–48 mya) in Pakistan, may accept been country tetrapods exhibiting all of the typical features of terrestrial mammals (Figure 14.2). A after stage (ca. 47 mya) in the evolution of cetaceans in the fossil evidence is exemplified by Ambulocetus natans, which shows signs of transition to aquatic morphology characterized by reduction of forelimbs but still retains well-developed hind limbs with webbed feet, reminiscent of hind limbs of the sea otter. Information technology probably swam by vertical axial undulations of the spine, while using hind limbs like a fluke. The adjacent stage (ca. 40 mya) in the evolution of cetaceans is the elongation of the torso and increment in the number of vertebrae also as marked vestigialization of hind limbs (Basilosaurus) indicating adaptation to a fully aquatic life (Thewissen and Bajpai, 2001). At a final stage of evolution of cetaceans, flukes evolved, and the swimming by axial undulation was complemented by tail oscillations.

Evolution of terrestrial mammals into marine swimmers followed, and/or was correlated with, changes in locomotory and other behaviors that the aquatic life imposed. Adaptive changes in the locomotory behavior and accompanying changes in morphology in the course of development of aquatic mammals tin can be illustrated with eclectic examples of mod animals that presumably are in the process of the evolutionary accommodation to the aquatic life (Figures 14.3–14.7).

In brusk, minks (Mustela vison) paddle quadrupedally (Figure xiv.4), and freshwater otters (Lontra canadensis) (Figure 14.5) swim mainly with their hind limbs (pelvic paddling), although they derive some additional lift from the tail (pelvic undulation). The body of water otter, Enhydra lutris (Figure 14.6), uses its highly asymmetrical anxiety equally the propelling surfaces, but near of the power for the movements comes from undulations of the vertebral cavalcade (pelvic undulation) rather than from the muscles of the hind limbs. The giant S American freshwater otter, Pteronura brasiliensis, uses caudal undulations: sinusoidal motions of the vertebral column, similar a wave moving through the entire spine, power a long and narrow tail that is dorsoventrally flat (Effigy 14.vii). No otter swims like a modern cetacean, simply the swimming mode of Pteronura approximates whale pond. Modern cetaceans differ from Pteronura in having a rigid body with most of the movement concentrated at one point: undulation, thus, became oscillation. In addition, mod cetaceans evolved a fluke (Thewissen and Bajpai, 2001).

Given that the loss of limbs is a procedure of adaptation to new atmospheric condition of living (aquatic, fossorial, or dense grass environment), animals offset had to acquire new modes of limbless locomotion (e.yard., lateral undulation, swimming undulation, concertina). The procedure of learning may accept been facilitated by the fact that ancestral motor patterns and fixed motor patterns (FAPs) during evolution are conserved, and motor circuits generating these FAPs could be activated under stressful habitat conditions. Indeed, all of the basic modes of locomotion, swimming (undulatory waves passing downwardly the body), crawling, and lateral undulation are functions of a unmarried motor pattern circuit that evolved in invertebrate ancestors. The motor blueprint for swimming was not lost in tetrapods adapted to terrestrial life, and most tetrapods are still capable of learning to swim.

Concertina locomotion (Figure fourteen.8A) implies that some part of the body is fixed on the ground in order to push the balance of the body frontwards. While this form of locomotion is widespread among burrowing snakes, another form, the so-called internal concertina, has been adopted by many caecilians, limbless ophidian-like amphibians (Figure 14.eightB). This manner of locomotion consists in undulatory movements performed by vertebral column only (not the torso every bit a whole).

Changes in the locomotory behavior preceded and facilitated vestigialization and loss of hind limbs in the development of these aquatic mammals from terrestrial tetrapods (Figure fourteen.9). Two crucial steps in this process were a reduction of the time of expression of Shh in the hind limb bud and afterwards a loss of ZPA in the hind limbs (Thewissen et al., 2006).

Information technology is noteworthy that during the ontogeny, cetaceans develop hind limb buds showing all the initial steps of terrestrial mammal limb bud evolution, including cell differentiation, formation of both signaling centers, the AER and ZPA, innervation, and secretion of FGF8, before entering the regression stage, as a result of Shh suppression. It is believed that the evolutionary reduction of the expression of Shh in the limb bud of aquatic mammals (and the corresponding limb reduction) started ca. 41 mya, whereas the total loss of Shh expression (and resulting loss of hind limbs) occurred ca. 34 mya (Thewissen et al., 2006).

Embryos of the limbless river mammal Stenella attenuata also develop limb buds. The limb bud grows to attain a length of 10–30 cm before starting regressive processes that lead to their reduction and total disappearance. Moreover, individuals with vestigial hind limbs are observed, at a low frequency, amid the adult populations of the spotted dolphin (Sedmera et al., 1997). The sperm whale ( Physeter catadon) is the simply toothed whale with a hind limb skeleton (fifteen cm long), although its expression is variable (Hall, 1995). Reduction of limb development in whales is extreme, but rudiments of the tetrapod bones are nowadays and 37% of individuals of the Antarctic population of minke whale have ossified femoral rudiment. Sometimes the following are also observed:

Atavistic skeletal elements can be surprisingly complete; 79 cm long bones in 125 cm long left and right "hindlimbs" in a female humpback whale.

Bejder and Hall (2002)

As for development of flippers from terrestrial mammalian limbs in the spotted dolphin, like other cetaceans, these organs, plain adaptations for aquatic life, have retained the inner mammalian limb structure, except for a marked increment in the number of phalanges, which is clearly an adaptation for the aquatic life (Sedmera et al., 1997).

The brief review of the normal development of limbs in tetrapods in Affiliate 13 (Section Role of the Nervous System in Limb Development) may be illuminating on the possible mechanisms of the evolutionary loss of limbs in limbless vertebrate groups.

Neo-Darwinian Explanation of Loss of Limbs

No changes in the office of the "limb-determining" or other relevant genes, other key limb-inducing genes or regulatory regions are involved in the loss of limbs in vertebrates, equally is proven, amidst other things, by the fact that most of the limbless species initially actuate the genes, form AER and ZPA, and even develop limbs to advanced stages earlier arresting their development or starting the programmed jail cell death of limb tissues.

From the neo-Darwinian view, the occurrence of such radical morphological differences every bit the presence and absence of limbs, eastward.g., exteriorization and posteriorization of limb buds, betwixt species that accept functionally unchanged all of the limb-determining genes (including Hox genes) is unexplainable at best.

Epigenetic Explanation

A await at expression patterns of HoxC-eight gene shows that in both chicks and mice embryos information technology is expressed in the midthoracic mesoderm and in the brachial region of the neural tube. Nonetheless, the anterior boundary of expression extends less anteriorly in chicks than in mice, thus determining the longer cervical region, more posterior advent of limb bud likewise equally the smaller number of thoracic segments in chickens (Effigy 14.x). It is noteworthy that the anterior boundary of HoxC-8 expression in both species coincides with the site of origin of the brachial nerves that innervate limbs (Bejder and Hall, 2002). Likewise remember, expression of Hox genes in general, and HoxC-eight in detail, are regulated by RA, which downregulates expression of posterior Hox genes along the embryonic anterior–posterior and causes corresponding truncation of the embryo (Kessel, 1992).

Genes for RA synthesis enzymes in vertebrates have not changed. What has inverse is the spatiotemporal pattern of expression of RA in limbed and limbless tetrapods every bit well as in chickens and mice, as shown in Figure 14.x. This change is clearly nongenetic (all of the limb-inducing genes are nowadays and functional in both limbed and limbless species).

Where may be the source of the epigenetic information that is used for these adaptive changes in expression patterns of Hox and other genes involved in the development of limbs or leading to limblessness in tetrapods?

The evidence presented in this chapter as well as in Chapter 13 (Department Part of the Nervous Organization in Limb Development) on the evolution of limbs in vertebrates shows that RA signals from the neural tube and local innervation are essential for the evolution of limbs in tetrapods.

In the process of vertebrate limb loss and reduction are too involved mechanisms of programmed cell death, which are epigenetically regulated every bit well. The procedure of apoptosis that leads to regression of the limb bud is known to be related to the fact that the AER does not secrete FGF, specially FGF8 and FGF4 (Boulet et al., 2004).

As shown earlier (Sections Apoptosis in Invertebrates and Neural Control of Apoptosis in Affiliate v), the programmed cell expiry during the individual evolution is epigenetically determined via point cascades that ultimately originate in the nervous arrangement.

Read full chapter

URL:

https://www.sciencedirect.com/scientific discipline/article/pii/B9780124158313000148

Whaling, Aboriginal and Western Traditional

Richard Ellis , in Encyclopedia of Marine Mammals (Third Edition), 2018

I Humans Run across Whales

One of the primeval records of human's interactions with whales can be found in the chronicles of the conquests of Alexander the Slap-up, which took place in the 4th century BC, and were transcribed some 300 years later by the Greek historian Arrian, probably of sperm whales ( Physeter macrocephalus), but likewise baleen whales, every bit being encountered at sea, and of people building parts of their houses with whale bones and jaws (all parts of western whaling summarized in more detail in Ellis, 2009a,b). Equally early as 350 BC, Aristotle (translation 1910) recognized that whales were mammals and not fish. Pliny the Elderberry (who often relied upon Aristotle and other authors) included whales in his Naturalis Historia, written soon before he was killed at Pompeii in the AD 79 eruption of Vesuvius (Pliny, translation 1933).

Much of what was known nigh whales came from beached carcasses. Aristotle (translation 1910) wrote, "it is not known for what reason they run themselves aground on dry land, at all events it is said that they exercise so at times, and for no obvious reason." In the 22 centuries that have elapsed since Aristotle fabricated his comments, we have come no closer to solving the mystery of whale strandings than the Greeks (although see Strandings, this edition). Beached whales represented the outset important contact between men and whales that would set the tone for the interaction of these two mammals for centuries.

Every species of whale has come aground, but the most celebrated of all stranders is the sperm whale. With its great square head filled with a mysterious waxy substance, its wrinkled hide and peg-like ivory teeth, a sperm whale appearing on the beach became a crusade célèbre. In many of the early descriptions of beached whales, the species is open to question, simply in one case y'all take seen Physeter, in that location is no possibility of confusing information technology with any other animal on earth, let alone any other whale.

Effectually 1577, the beginning engraving of a stranded whale appeared in print. By the plow of the 17th century, more than whales had stranded on European coasts, and with the heightened interest in popular science, more than engravings appeared. Either because the whales preferred the coasts of kingdom of the netherlands, or because the Dutch had a item interest in stranded whales, the bulk of the early illustrations of whales were the work of Low Country artists. In these elaborately detailed drawings, the good burghers of Holland are oftentimes seen perched upon the carcass, standing around in fashionable attire, or occasionally carrying off a bucket of what may very well take been whale oil.

The North Sea coast of Holland would appear to be one of those places (noteworthy others are in New Zealand and Cape Cod) where whales strand with some caste of regularity. From 1531 to around 1690, some xl whales of assorted species beached themselves on these shingled coasts. Most of them seem to take been sperm whales, and with their huge heads, a mouthful of ivory teeth, and—in what appear to be a majority of the cases—its male person genitalia prominently exposed, the dead whale must accept been a wonder of wonders to the Dutchmen who came to view these monsters. It would be some other one-half-century earlier whalers of Rotterdam and Delft would head for the icy seas of Spitsbergen, where they would hunt a totally different beast, the Greenland right whale (or bowhead whale, Balaena mysticetus).

Non all knowledge of whales came from those that beached; seafarers encountered cetaceans as they plied their trade routes or began their hesitant explorations of distant coasts. Men sailed from the ports of Europe, Asia, and Africa; for conquest, for trade, or to spread the word of their god, but they did not set sail casually. Discovery equally an cease in itself, exploration in intellectual pursuit of geographical knowledge, or in the romantic pursuit of unusual adventure, is characteristic of a safer, richer, more comfortable society than that of 15th century Europe (Parry, 1974). There was no such thing as science for the sake of science, and if men found whales, they took them for what they believed them to be: huge, mysterious, threatening creatures. On their early maps, they figured them as large, scaly animals with a frightening assortment of unlikely appendages: horns, fringes, crests, armor, lumps, bumps, ridges, horrific dentition, and often twin pipes gushing h2o into the air.

Information technology was non the intention of early western mapmakers to frighten their fellow men; everyone believed that foreign lands harbored mysterious animals and every bit strange varieties of men. For medieval man, these superstitions proved to be true, as the bounding main spewed along monsters larger and more terrible than any animal imaginable. There are giant squid with arms fifteen–20 m long, and at that place are leviathans. Although they did not have scales, horns or twin blowpipes, the leviathans had equally improbable characteristics: behemothic flattened tails, foreign plates where terrestrial mammals had teeth, gigantic reproductive organs (often grotesquely distended in death), and no legs where proper mammals were supposed to have legs. Who could fault the ancients for suspecting that the sea harbored monsters?

We have no mode of knowing when or where the first aborigines encountered the start beached whales, but it is obvious that this come across would somewhen lead to whaling. As soon as the inhabitants of what would become Kingdom of the netherlands, Norway, Japan, or Vancouver realized that they did not accept to depend on the uncertain generosity of the sea to provide a bounty of meat or oil, they would take to the sea themselves, to hunt the whale.

In that location is an almost consummate lack of data on Norse whaling, but the waters in which they sailed were then (and are even so) amidst the whale richest in the globe. There are right whales, humpbacks, fin whales, sperm whales, belugas (Delphinapterus leucas), narwhals, pilot whales (Globicephala spp.), and diverse species of dolphins in the cold, productive waters of the North Atlantic. The Norse sagas are silent on the subject of whales and whaling, simply information technology would be hard to imagine these hardy seafarers ignoring a plentiful source of nutrient and oil as they plied the otherwise inhospitable seas around Iceland, Greenland, and Labrador. There are references, however, to battles purple between diverse "families" equally they dispute the ownership of whale carcasses, which indicates the importance of whales—at least of dead whales—in the lives of the early Norsemen. They left no tryworks, their settlements provide no trace of harpoons or lances, merely at that place are tantalizing hints of Norse whaling in some of the more recent discussions. In his History of Whaling, Sydney Harmer (1928) says, "The Icelanders seem to take engaged in whaling … and the whale known as 'Slettibaka' … is believed to have been the Biscay whale." (The modernistic Icelandic for the right whale is sletbag, which means "smooth back.")

Read full chapter

URL:

https://www.sciencedirect.com/science/article/pii/B9780128043271002697

Alimentary canal

James G. Mead , in Encyclopedia of Marine Mammals (Second Edition), 2009

3 Cetacea

The cetacean stomach is a diverticulated composite tum, consisting of regions of stratified squamous epithelium, fundic mucosa, and pyloric mucosa. The stomach, as typified by a delphinids, consists of 4 chambers. These have been referred to by various anatomical terms: forestomach (first, esophageal compartment, paunch) main tummy (second, cardiac, fundus glandular, proximal), connecting chamber (3rd, 4th, "narrow tunneled passage," "conduit ètroit," intermediate, connecting aqueduct, connecting segmentation), and pyloric tummy (third, fourth, 5th, pyloric glandular, distal).

A Forestomach

There is no total consensus about the homology of the forestomach in Cetacea. It is lined with stratified squamous epithelium, such as the esophagus, and in that location was reason to believe that information technology was just an esophageal sacculation. Embryological work in the minke whale (Balaenoptera acutorostrata) demonstrated that the forestomach was formed from the tummy bud, but that the esophagus was non. This indicates that the cetacean esophagus is homologous to the forestomach of ruminants.

The forestomach of delphinoids (also called paunch) is lined with stratified squamous not-keratinized epithelium. The epithelial lining is white in freshly dead animals and is thrown into a series of longitudinal folds when empty. Similar to the other chambers in the tum it is variable in size. It is pyriform and on the gild of xxx-cm long in an adult Tursiops truncatus (280 cm total length). The forestomach is highly muscular but has no glandular functions. The forestomach/chief breadbasket aperture is a broad opening (three–v cm in adult Tursiops) in the wall of the forestomach near the esophageal end. The forestomach functions as a holding cavity coordinating to the crop of birds or the forestomach of ungulates. Considering the communication with the chief stomach is then broad, there is a reflux of digestive fluids from the main tummy and some digestion takes identify in the forestomach. The same general relationships hold in Phocoena, Delphinapterus, and Monodon.

The forestomach of platanistoids is unusual in Inia geoffrensis and Platanista gangetica in that the esophagus runs direct into the main stomach and the forestomach branches off the esophagus. In the two other genera of platanistids the forestomach is lacking entirely.

The forestomach is present in Physeter catodon, where it was approximately 140 by 140 cm and lined with xanthous-white epithelium in a 15.6 m male. The forestomach is absent in all ziphiids, and nowadays in all species of mysticetes.

B Main Stomach

The chief tum has a highly vascular, glandular epithelium which is grossly trabeculate. The epithelium of the principal breadbasket is dark pink to purple. The main breadbasket is the compartment which secretes most of the digestive enzymes and acids and in which identify digestion commences. It has likewise been known every bit the fundic tummy. It is present in all cetaceans.

In delphinoids, the master breadbasket is approximately spherical and on the order of ten–15 cm in adult Tursiops. The same general relationships hold in Phocoena, Delphinapterus, and Monodon. In Platanista there is a constricting septum of the master stomach which forms a small distal bedroom, through which the digesta must pass. Lipotes vexillifer presents an unusual state of affairs in having three serially arranged main tum compartments. The second and tertiary compartments are very much smaller than the first and are topographically homologous with the connecting chambers. However they are lined by epithelium that has fundic glands, typical of the main tum.

There is nil remarkable about the primary stomach of physeteroids, but in some ziphiids there is a subdivision in their main stomach. At that place is an incipient constriction in the main stomach of Berardius bairdii and Mesoplodon bidens that divides the stomach into 2 compartments. The connecting chambers exit off the second compartment. Some other type of stomach modification has occurred in Mesoplodon europaeus and M. mirus, where a large septum has adult forming a blind diverticulum in the main tummy. An boosted septum has developed in the diverticulum in Mesoplodon europaeus subdividing information technology Fig. 2. In that location is nothing remarkable well-nigh the main tum in mysticetes.

C Connecting Chambers

The connecting chambers, also called the connecting aqueduct, the intermediate tummy, or the third stomach, are nowadays in all Cetacea. They are lined with pyloric epithelium and are easily overlooked in dissections. They are small in most cetaceans but have been greatly developed in ziphiids. Because of their proliferation in ziphiids, where they seem to function equally something more than channels between the chief and pyloric stomachs, their name was inverse from connecting channels to connecting chambers.

The connecting chambers in a typical delphinoid consist of two narrow compartments lying between the main tum and the pyloric stomach. The diameter of the connecting chambers is 0.8 cm in adult Tursiops and the combined length is vii–9 cm. The epithelial lining is very similar to the pyloric stomachs. In some species the compartments are simple, serially arranged; in others they may have diverticulae. The same general relationships hold in Phocoena,Delphinapterus,and Monodon.

Connecting chambers occur in all the species of platanistids, with the exception of Lipotes. In that species, the compartments lying between the master stomach and the pyloric stomach (second and third compartments of the main tummy) are lined with epithelium containing fundic and mucous glands in the beginning compartment and fundic glands in the second compartment. This would make them subdivisions of the main stomach.

The connecting chambers in ziphiids are globular compartments, ranging in number from 3 to xi. They are separated by septa and communicate by openings in the septa. The openings are sometimes central in the septa, sometimes peripheral. The connecting chambers are lined with pyloric epithelium. The connecting chambers in specimens of adult Mesoplodon (∼5 m long) are about x cm in diameter.

Many workers have described the connecting chambers in a number of species of Balaenoptera (blueish, B. musculus; fin, B. physalus; sei, B. borealis; minke, B. acutorostrata and B. bonaerensis). The connecting chambers in common minke whales were 10–30 cm in length. The inflated connecting chambers in an viii.5-m female Balaena mysticetus were 5 cm in bore and 17 cm combined length. The presence of connecting chambers was non mentioned in dissections of right whales. The connecting chambers are relatively large in a newborn Eschrichtius.

D Pyloric Tum

The pyloric stomach in delphinoids is a simple tubular cavity lined by typical mucous producing pyloric glands. The epithelium is in many means similar to the epithelium of the small intestine. The pyloric stomach is almost 20-cm long and 4 cm in flat diameter in an adult Tursiops. The same general relationships hold in Phocoena, Delphinapterus, and Monodon.

The pyloric stomach in P. gangetica is a single sleeping accommodation about 12-cm long and contains abundant large tubular pyloric glands. The pyloric breadbasket is comparable in Inia and Pontoporia merely differs markedly in Lipotes. In that species it is differentiated into a proximal bulbous compartment and a smaller distal compartment. The epithelial lining in Lipotes is similar to all other Cetacea.

The bachelor information on the pyloric breadbasket of physeteroids is scanty. The pyloric compartment is present and there is no reason to assume that it is different from the rest of the cetaceans. The pyloric stomach in a newborn Ziphius was a simple spherical compartment that measured nigh 10 cm in bore. Information technology was lined with smooth pyloric epithelium and communicated with the duodenum through a strong pyloric sphincter. This is also the case in Hyperoodon, Tasmacetus, and some species of Mesoplodon (M. densirostris, Grand. hectori, and M. stejnegeri). In B. bairdii the main pyloric compartment has expanded in book to where it is nigh the size of the primary stomach, and has developed a small distal accompaniment bedroom. The pyloric compartments are in series, accessory chamber lies betwixt it and the duodenum. In all other species of Mesoplodon examined to date (M. bidens, M. europaeus, and K. mirus), a blind diverticulum has adult. The diverticulum comes off the proximal side of the pyloric stomach and lies forth the distal connecting chambers. The accompaniment pyloric stomach communicates with the pyloric stomach through a wide opening.

In all of the balaenopterid species examined (B. acutorostrata, B. borealis, B. musculus, and B. physalus), the pyloric stomach is smaller than the primary stomach. The pyloric breadbasket contained 8.5–12.1% of the total inflated stomach volume (eighteen–39 ). It is lined with smooth pyloric epithelium. In balaenids and newborn Eschrichtius, the pyloric stomach appears to be similar to that of balaenopterids.

Read total chapter

URL:

https://www.sciencedirect.com/science/commodity/pii/B9780123735539001139

Cetacean Environmental

Lisa T. Ballance , in Encyclopedia of Marine Mammals (Third Edition), 2018

III Prey

A What Do Cetaceans Swallow?

Most of what is known almost the nutrient of cetaceans comes from information collected from expressionless animals, through directed fisheries, incidental bloodshed, or strandings; though increasingly, noninvasive methods (stable isotope or fat acid analysis from pare and blubber biopsy samples) are providing significant insights.

In that location are four general types of cetacean prey. The starting time tin can be characterized by pocket-sized individuals that school at relatively shallow depths (surface to several hundred meters). These are primarily planktonic crustaceans (euphausiids, copepods, amphipods) and small fish (e.g., herring (Clupea spp.), sardine (Sardinops spp.), anchovy (Engraulidae), sandlance (Ammodytidae)). They tend to occur in temperate or polar seas or in those tropical latitudes that are associated with loftier productivity (due east.g., eastern boundary currents). They more often than not occur at low trophic levels, take pocket-sized torso sizes, and occur in dumbo aggregations. Accordingly, the cetaceans feeding upon them capture multiple individuals simultaneously, have big body sizes, and take evolved filtering mechanisms (baleen) to strain prey items from the water. All mysticetes feed on this prey type.

The 2d casualty type is comprised of larger organisms that also schoolhouse at relatively shallow depths (surface to several hundred meters), or migrate up to shallow depths during the night. This includes many pelagic fishes (e.thousand., hake (Merluccius spp.), pollock (Pollachius spp., Theragra spp.), myctophids (Myctophidae)), and schooling squids (Loligo spp., Dosidicus spp.) that occur throughout the world's oceans. Because these prey are larger, they more often than not occupy higher trophic levels and are captured individually. Their cetacean predators typically have smaller body sizes. They include all of the big-schooling dolphins and some small-schooling or lone species. These cetaceans tend to have a high tooth count, pointed teeth, and pointed snouts, all adaptations for pursuing fast, individual prey.

The third prey type is comprised of big, lone squid (e.g., Gonatus spp.). These are nigh often constitute in deep waters throughout the globe's oceans. Because of their size and alone habits, they are captured individually. Cetacean predators of these casualty include the sperm whale ( Physeter microcephalus), dwarf and pygmy sperm whales (Kogia spp.), all of the beaked whales (Ziphiidae), and pilot whales (Globicephala spp.). These cetaceans are deep defined and tend to have reduced dentition, rounded heads, and well-developed melons, the latter mayhap indicative of the importance of echolocation for prey detection in the dark depths.

The final prey type includes species at loftier trophic levels that are themselves peak predators. These include predatory fishes (e.m., tunas (Scombridae), sharks, salmonids), marine birds, pinnipeds, and cetaceans, including the largest of whales (rorquals (Balaenoptera spp.) and sperm whales). Few cetaceans are able to accept these prey items. They include the killer whale (Pitman et al., 2011 and references therein) and, possibly, faux killer whale (Pseudorca crassidens), and airplane pilot whales. Killer whale ecotypes that specialize on fish, pinnipeds, sharks, and cetaceans are known from the northeastern Pacific, Due north Atlantic, and Antarctic ocean. The bear on of this predation has been hotly debated simply may exist meaning (run into below).

B How Exercise Cetaceans Capture Prey?

Cetaceans have two main types of feeding appliance: baleen and teeth. Baleen is used for straining prey items from the water or, in the example of the benthic-feeding gray whale, from the sediment. Teeth are used for communicable individual prey items. Species with a high tooth count employ them to grasp individual prey; those with a low molar count tend to be suction feeders.

Most of what is known about prey capture strategies is relevant to cetaceans that feed on small prey that school at relatively shallow depths (the mysticetes). This is because it is relatively easy to observe these animals feeding in the wild. Mysticetes have baleen plates suspended from the roof of their mouths that they use to strain prey items from the water. The number of baleen plates, their length, and the density of baleen fibers per plate vary between species and are correlated with prey size. The Balaenidae (right and bowhead whales) and sei whales (B. borealis) have the greatest number of plates with the finest filtering strands and feed mainly on tiny copepods. Bluish whales and most other rorquals have an intermediate number of plates with coarser filtering strands and feed on larger prey items such as euphausiids and small fishes. Grey whales have the fewest number of plates with the coarsest strands and are largely lesser feeders, sifting benthic infauna from muddy substrate.

In improver to specializing on different prey sizes, baleen whales have specialized feeding methods that as well correlate with the morphology of their baleen. "Skimmers" (Balaenidae) swim slowly with their mouths open through dense clouds of deadening-swimming copepods. "Gulpers" (almost rorquals) lunge into dense schools of euphausiids or fishes with their mouths open, endmost them rapidly to trap their prey. All rorquals have gular grooves that run forth the ventral surface of the oral cavity and pharynx, which permit the buccal cavity to expand during a lunge, taking in huge quantities of water, and with this, prey (Fig. two). A variation on this type of feeding is used by humpback whales (Megaptera novaeangliae) when they form "bubble nets": streams of bubbling emitted from the blowhole equally the whale swims in a circular blueprint toward the surface. The bubbles class an ascending curtain, which concentrates prey inside. Most of these cetaceans are lonely feeders only they regularly amass in areas of high prey density and, when prey are extremely dense, volition feed cooperatively at times, through bubble-net feeding or in staggered echelon formations.

Cetaceans that feed on larger fish and squid that school at relatively shallow depths capture individual prey items and eat them whole. High speed is important, every bit is vision. Typically, these predators forage cooperatively, herding prey into tight aggregations and capturing them in turn. Acoustic signaling is presumably important for the coordination of schooling activities. Some cetaceans in this group feed as individuals, particularly those found in coastal areas. They show a wide range of prey capture behaviors, including slapping fish with their flukes and deliberately stranding themselves on the embankment in pursuit of fishes.

Cetaceans taking big, alone squid feed at depth, in partial to full darkness. For this reason, not much is known virtually how they capture prey. They probably practise non feed cooperatively because their casualty practice not school and because about of these cetaceans occur in small schools and are slow swimming. Most take reduced dentition, and evidence indicates that they are suction feeders, using the gular muscles and tongue in a piston-like activeness to suck prey into their mouths (Heyning and Mead, 1996). How they are able to get close plenty to their prey to suck them in remains a mystery. One relatively dated though to this day intriguing idea is that they are able to partially stun prey with echolocation bursts (Norris and Møhl, 1983).

Cetaceans that casualty upon tiptop predators bear witness a broad range of prey capture methods and hunt as individuals and cooperatively in groups, depending upon prey size and characteristics. For example, killer whales may accept pinnipeds past beaching themselves intentionally to catch adults and pups from rookeries simply hunt cooperatively to accept dolphins and large whales. Cooperative behaviors include prey encirclement and capture, sectionalization of labor during an attack, and sharing of casualty. Among the more spectacular of these is the formation of a wave by (presumably) family groups of pack water ice killer whales (Blazon B) to wash seals off ice floes in waters surrounding the Antarctic Peninsula (Pitman and Durban, 2012).

C How Do Cetaceans Locate Prey?

Most cetaceans are visual predators, at least in part. For odontocetes, echolocation is equally if not more important in locating and targeting prey. Although not comprehensively confirmed, all odontocetes are causeless to echolocate and to employ this sense extensively when foraging. At present, there is no evidence that mysticetes have the ability to echolocate, although they exercise produce low-frequency sounds that travel long distances (hundreds of kilometers). The long wavelengths of these pulses cannot resolve features finer than the wavelengths themselves (tens of meters), and so, it is hundred-to-one that they could be used to locate and target prey patches. The effective range of vision and echolocation is a function of water properties and species-specific echolocation abilities, but both are probably limited to distances on the order of hundreds of meters to a few kilometers.

On a larger spatial scale, especially in oceanic waters, patchiness and variability in space and time are feature of about marine ecosystems and piffling is known about how cetaceans locate prey in such environments. Presumably, many species simply travel large distances in a continuous search. This is particularly likely to be the example in regions of low productivity such every bit the oceanic tropics, where casualty patches are few and far between. Here, schooling may increase the chances of encountering a patch (the more eyes and ears, the better), and dolphin schools accept been observed moving through the water in wide line-abreast formations, patently searching for prey.

There are circumstances under which prey occur predictably in space and time, and a wide range of examples indicate that cetaceans search for and exploit these opportunities. Oceanographic (e.g., boundaries between currents, eddies, and water masses) and topographic (e.m., continental shelf-slope breaks, islands, seamounts) features increase prey abundance or availability by enhancing primary production, by passively carrying planktonic organisms, and by maintaining property gradients (e.g., fronts) to which prey (and cetacean predators) actively respond. An entire customs of fishes and invertebrates lives at depth during the day and migrates to the surface at night when spotted, spinner, dusky, and common dolphins exploit them. Flotsam (natural or of anthropogenic origin) aggregates communities of animals at a wide range of trophic levels and rough-toothed dolphins (Steno bredanensis) oftentimes occur in association with these communities (Pitman and Stinchcomb, 2002). Killer whales amass effectually pinniped rookeries when young seals and bounding main lions are weaning, and a number of cetacean species associate with fishing operations to take their discards or target species through depredation (east.g., Schakner et al., 2014).

Read full chapter

URL:

https://www.sciencedirect.com/science/article/pii/B978012804327100087X

richardslifeastrom.blogspot.com

Source: https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/physeter

What Family Does the Sperm Whale Belong to

Sperm Whale

I Characteristics and Taxonomy

Acoustic Scattering past Marine Organisms*

Marine Mammals

Sperm Whales, Evolution

II Kogiidae

Anatomy of the Viscera

Sperm and Beaked Whales, Evolution

I Sperm Whales, Fossil Record, and Phylogeny

Marine Ecosystems of Andaman and Nicobar Islands – Species Abundance and Distribution

iv.10 Marine Mammals Biodiversity and Distribution

Development past Loss

Loss/Reduction of Limbs in Aquatic Mammals

Neo-Darwinian Explanation of Loss of Limbs

Epigenetic Explanation

Whaling, Aboriginal and Western Traditional

I Humans Run across Whales

Alimentary canal

3 Cetacea

A Forestomach

B Main Stomach

C Connecting Chambers

D Pyloric Tum

Cetacean Environmental

III Prey

A What Do Cetaceans Swallow?

B How Exercise Cetaceans Capture Prey?

C How Do Cetaceans Locate Prey?

0 Response to "What Family Does the Sperm Whale Belong to"

Post a Comment

Iklan Atas Artikel

Iklan Tengah Artikel 1

Iklan Tengah Artikel 2

Iklan Bawah Artikel