genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

sperm whale The sperm whale or cachalot (''Physeter macrocephalus'') is the largest of the toothed whales and the largest toothed predator. It is the only living member of the genus '' Physeter'' and one of three extant species in the sperm whale famil ...

biblical The Bible (from Koine Greek , , 'the books') is a collection of religious texts or scriptures that are held to be sacred in Christianity, Judaism, Samaritanism, and many other religions. The Bible is an anthologya compilation of texts of a ...

Leviathan Leviathan (; he, לִוְיָתָן, ) is a sea serpent noted in theology and mythology. It is referenced in several books of the Hebrew Bible, including Psalms, the Book of Job, the Book of Isaiah, the Book of Amos, and, according to so ...

Herman Melville Herman Melville (born Melvill; August 1, 1819 – September 28, 1891) was an American novelist, short story writer, and poet of the American Renaissance period. Among his best-known works are ''Moby-Dick'' (1851); '' Typee'' (1846), a r ...

Moby-Dick ''Moby-Dick; or, The Whale'' is an 1851 novel by American writer Herman Melville. The book is the sailor Ishmael's narrative of the obsessive quest of Ahab, captain of the whaling ship ''Pequod'', for revenge against Moby Dick, the giant white ...

Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = Seal (emblem), National seal , national_motto = "Fi ...

Tortonian The Tortonian is in the geologic time scale an age or stage of the late Miocene that spans the time between 11.608 ± 0.005 Ma and 7.246 ± 0.005 Ma (million years ago). It follows the Serravallian and is followed by the Messinian. The Tort ...

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" ...

epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided by ...

year A year or annus is the orbital period of a planetary body, for example, the Earth, moving in its orbit around the Sun. Due to the Earth's axial tilt, the course of a year sees the passing of the seasons, marked by change in weather, the ...

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the eas ...

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, t ...

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring count ...

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58macroraptorial sperm whales (or "raptorial sperm whales") and was probably an

apex predator An apex predator, also known as a top predator, is a predator at the top of a food chain, without natural predators of its own. Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the highest trophic le ...

, preying on whales, seals, and so forth. Characteristically of raptorial sperm whales, ''Livyatan'' had functional, enamel-coated teeth on the upper and lower jaws, as well as several features suitable for hunting large prey. ''Livyatan''s total length has been estimated to be about , similar to that of the modern

sperm whale The sperm whale or cachalot (''Physeter macrocephalus'') is the largest of the toothed whales and the largest toothed predator. It is the only living member of the genus '' Physeter'' and one of three extant species in the sperm whale famil ...

(''Physeter macrocephalus''), making it one of the largest predators known to have existed. The teeth of ''Livyatan'' measured , and are the largest biting teeth of any known animal, excluding tusks. It is distinguished from the other raptorial sperm whales by the basin on the skull, spanning the length of the

snout A snout is the protruding portion of an animal's face, consisting of its nose, mouth, and jaw. In many animals, the structure is called a muzzle, rostrum, or proboscis. The wet furless surface around the nostrils of the nose of many mammals is ...

. The

spermaceti organ The spermaceti organ is an organ present in the heads of toothed whales of the family Physeteroidea, in particular the sperm whale. This organ contains a waxy liquid called spermaceti and is involved in the generation of sound. Description In ...

, contained in that basin is thought to have been used in echolocation and communication, or for ramming prey and other sperm whales. The whale may have interacted with the large extinct shark

Megalodon Megalodon (''Otodus megalodon''), meaning "big tooth", is an extinct species of mackerel shark that lived approximately 23 to 3.6 million years ago (Mya), from the Early Miocene to the Pliocene epochs. It was formerly thought to be a me ...

(''Otodus megalodon''), competing with it for a similar food source. Its extinction was probably caused by a cooling event at the end of the Miocene period causing a reduction in food populations. The geological formation where the whale has been found has also preserved a large assemblage of marine life, such as sharks and

marine mammal Marine mammals are aquatic mammals that rely on the ocean and other marine ecosystems for their existence. They include animals such as Pinniped, seals, Cetacea, whales, Sirenia, manatees, sea otters and polar bears. They are an informal group, ...

s.

Taxonomy

Research history

In November 2008, a partially preserved skull, as well as teeth and the lower jaw, belonging to ''L. melvillei'', the holotype specimen MUSM 1676, were discovered in the coastal desert of Peru in the sediments of the Pisco Formation, southwest of the city of Ica. Klaas Post, a researcher for the Natural History Museum Rotterdam in the Netherlands, stumbled across them on the final day of a field trip. The fossils were prepared in

Lima Lima ( ; ), originally founded as Ciudad de Los Reyes (City of The Kings) is the capital and the largest city of Peru. It is located in the valleys of the Chillón, Rímac and Lurín Rivers, in the desert zone of the central coastal part of t ...

, and are now part of the collection of the Museum of Natural History, Lima of

National University of San Marcos The National University of San Marcos ( es, Universidad Nacional Mayor de San Marcos, link=no, UNMSM) is a public research university located in Lima, the capital of Peru. It is considered the most important, recognized and representative educ ...

. The discoverers originally assigned—in July 2010—the English name of the biblical monster, Leviathan, to the whale as ''Leviathan melvillei''. However, the scientific name ''Leviathan'' was also the junior synonym for the

mastodon A mastodon ( 'breast' + 'tooth') is any proboscidean belonging to the extinct genus ''Mammut'' (family Mammutidae). Mastodons inhabited North and Central America during the late Miocene or late Pliocene up to their extinction at the end of th ...

(''Mammut''), so, in August 2010, the authors rectified this situation by coining a new genus name for the whale, ''Livyatan'', from the original

Hebrew Hebrew (; ; ) is a Northwest Semitic language of the Afroasiatic language family. Historically, it is one of the spoken languages of the Israelites and their longest-surviving descendants, the Jews and Samaritans. It was largely preserved ...

name of the monster. The

species name In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bo ...

''melvillei'' is a reference to

Herman Melville Herman Melville (born Melvill; August 1, 1819 – September 28, 1891) was an American novelist, short story writer, and poet of the American Renaissance period. Among his best-known works are ''Moby-Dick'' (1851); '' Typee'' (1846), a r ...

, author of the book ''

Moby-Dick ''Moby-Dick; or, The Whale'' is an 1851 novel by American writer Herman Melville. The book is the sailor Ishmael's narrative of the obsessive quest of Ahab, captain of the whaling ship ''Pequod'', for revenge against Moby Dick, the giant white ...

'', which features a gigantic sperm whale as the main antagonist. The first ''Livyatan'' fossils from Peru were initially dated to around 13–12 million years ago (mya) in the

Serravallian The Serravallian is, in the geologic timescale, an age or a stage in the middle Miocene Epoch/ Series, which spans the time between 13.82 Ma and 11.63 Ma (million years ago). The Serravallian follows the Langhian and is followed by the Tort ...

Age of the Miocene, but this was revised to 9.9–8.9 mya in the

Tortonian The Tortonian is in the geologic time scale an age or stage of the late Miocene that spans the time between 11.608 ± 0.005 Ma and 7.246 ± 0.005 Ma (million years ago). It follows the Serravallian and is followed by the Messinian. The Tort ...

Age of the Miocene. During the late 2010s, fossils of large isolated sperm whale teeth were reported from various Miocene and Pliocene localities along the Southern Hemisphere. These teeth have been identified to be of similar size and shape with that of the ''L. melvillei'' holotype and may be species of ''Livyatan''. However, it is commonplace that authors do not identify such teeth as a conclusive species of ''Livyatan'', instead opting to assign an open nomenclature in which the biological classifications of the specimens are restricted to comparisons or affinities with ''Livyatan''. This is mostly because isolated teeth tend to not be informative enough to be identified at the species level, meaning that there is some undeterminable possibility that they belong to an undescribed close relative of ''Livyatan'' rather than ''Livyatan'' itself. In 2016 in Beaumaris Bay, Australia, a large sperm whale tooth measuring , specimen NMV P16205, was discovered in Pliocene

strata In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as e ...

by a local named Murray Orr, and was nicknamed the "Beaumaris sperm whale" or the "giant sperm whale". The tooth was donated to Museums Victoria at

Melbourne Melbourne ( ; Boonwurrung/ Woiwurrung: ''Narrm'' or ''Naarm'') is the capital and most populous city of the Australian state of Victoria, and the second-most populous city in both Australia and Oceania. Its name generally refers to a me ...

. Though it has not been given a species designation, the tooth looks similar to those of ''L. melvillei'', indicating it was a close relative. The tooth is dated to around 5mya, and so is younger than the ''L. melvillei'' holotype by around 4or 5million years. In 2018, palaeontologists led by David Sebastian Piazza, while revising the collections of the Bariloche Paleontological Museum and the Municipal Paleontological Museum of Lamarque, uncovered two incomplete sperm whale teeth cataloged as MML 882 and BAR-2601 that were recovered from the Saladar Member of the Gran Bajo del Gualicho Formation in the Río Negro Province of

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, t ...

, a deposit that dates between around 20-14 mya. The partial teeth measure and in height respectively. Anatomical analyses of the specimens found that much of their characteristics are identical to ''L. melvillei'' except in width, in which the diameter of both teeth are smaller. Because of this, along with only isolated teeth being available, the palaeontologists chose to assign an open nomenclature, identifying both specimens as ''aff. Livyatan sp.'' In 2019, palaeontologist Romala Govender reported the discovery of two large sperm whale teeth from Pliocene deposits near the

Hondeklip Bay Hondeklip Bay ( af, Hondeklipbaai, which translates as ''dog stone bay'') is a coastal village in the Namakwa district of the Northern Cape province of South Africa. It lies about 95 km south west of the district capital Springbok. This vi ...

village of

Namaqualand Namaqualand ( khoekhoe: "Nama-kwa" meaning Nama Khoe people's land) is an arid region of Namibia and South Africa, extending along the west coast over and covering a total area of . It is divided by the lower course of the Orange River in ...

in

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring count ...

. The pair of teeth, which are stored in the Iziko South African Museum and cataloged as SAM-PQHB-433 and SAM-PQHB-1519, measure and in height respectively, the latter having its crown missing. Both teeth have open pulp cavities, indicating that both whales were young. The teeth are very similar in shape and size to the mandibular teeth of the ''L. melvillei'' holotype, and were identified as ''cf. Livyatan''. Like the Beaumaris specimen, the South African teeth are dated to around 5mya.

Phylogeny

''Livyatan'' was part of a fossil

stem group In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor ...

of hyper-predatory

sperm whales The sperm whale or cachalot (''Physeter macrocephalus'') is the largest of the toothed whales and the largest toothed predator. It is the only living member of the genus '' Physeter'' and one of three extant species in the sperm whale famil ...

commonly known as macroraptorial sperm whales, or raptorial sperm whales, alongside the extinct whales '' Brygmophyseter'', '' Acrophyseter'', and '' Zygophyseter''. This group is known for having large, functional teeth in both the upper and lower jaws, which were used in capturing large prey, and had an enamel coating. Conversely, the modern

sperm whale The sperm whale or cachalot (''Physeter macrocephalus'') is the largest of the toothed whales and the largest toothed predator. It is the only living member of the genus '' Physeter'' and one of three extant species in the sperm whale famil ...

(''Physeter macrocephalus'') lacks teeth in the upper jaw, and the ability to use its teeth to catch prey. ''Livyatan'' belongs to a different lineage in respect to the other raptorial sperm whales, and the size increase and the development of the

spermaceti organ The spermaceti organ is an organ present in the heads of toothed whales of the family Physeteroidea, in particular the sperm whale. This organ contains a waxy liquid called spermaceti and is involved in the generation of sound. Description In ...

, an organ that is characteristic of sperm whales, are thought to have evolved independently from other raptorial sperm whales. The large teeth of the raptorial sperm whales either evolved once in the group with a basilosaurid-like common ancestor, or independently in ''Livyatan''. The large temporal fossa in the skull of raptorial sperm whales is thought to a

plesiomorphic In phylogenetics, a plesiomorphy ("near form") and symplesiomorphy are synonyms for an ancestral character shared by all members of a clade, which does not distinguish the clade from other clades. Plesiomorphy, symplesiomorphy, apomorphy, an ...

feature, that is, a trait inherited from a common ancestor. Since the teeth of foetal modern sperm whales (''Physeter macrocephalus'') have enamel on them before being coated with

cementum Cementum is a specialized calcified substance covering the root of a tooth. The cementum is the part of the periodontium that attaches the teeth to the alveolar bone by anchoring the periodontal ligament.Illustrated Dental Embryology, Histology, ...

, it is thought that the enamel is also an ancient characteristic (

basal Basal or basilar is a term meaning ''base'', ''bottom'', or ''minimum''. Science * Basal (anatomy), an anatomical term of location for features associated with the base of an organism or structure * Basal (medicine), a minimal level that is nec ...

). The appearance of raptorial sperm whales in the fossil record coincides with the diversification of

baleen whale Baleen whales ( systematic name Mysticeti), also known as whalebone whales, are a parvorder of carnivorous marine mammals of the infraorder Cetacea ( whales, dolphins and porpoises) which use keratinaceous baleen plates (or "whalebone") in th ...

s in the

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" ...

, implying that they evolved specifically to exploit baleen whales. It has also been suggested that the raptorial sperm whales should be placed into the subfamily Hoplocetinae, alongside the genera ''

Diaphorocetus ''Diaphorocetus'' is an extinct genus of odontocete cetacean belonging to Physeteroidea. Its remains were found in the Monte León Formation of Argentina, dating to the Early Miocene.Idiorophus'', '' Scaldicetus'', and ''

Hoplocetus ''Hoplocetus'' is an extinct genus of raptorial cetacean of the sperm whale superfamily (biology), superfamily, Physeteroidea. Its remains have been found in the Miocene of Belgium, France, Germany and Malta, the Pliocene of Belgium and France, a ...

'', which are known from the Miocene to the lower

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58wastebasket taxa Wastebasket taxon (also called a wastebin taxon, dustbin taxon or catch-all taxon) is a term used by some taxonomists to refer to a taxon that has the sole purpose of classifying organisms that do not fit anywhere else. They are typically defined ...

for non-diagnostic material of stem physeteroids. This subfamily is characterized by their robust and enamel-coated teeth. The cladogram below is modified from Lambert et al. (2017) and represents the phylogenetic relationships between ''Livyatan'' and other sperm whales, with genera identified as macroraptorial sperm whales in bold.

Description

The body length of ''Livyatan'' is unknown since only the holotype skull is preserved. Lambert and colleagues estimated the body length of ''Livyatan'' using ''Zygophyseter'' and modern

sperm whales The sperm whale or cachalot (''Physeter macrocephalus'') is the largest of the toothed whales and the largest toothed predator. It is the only living member of the genus '' Physeter'' and one of three extant species in the sperm whale famil ...

as a guide''.'' The authors opted to use the relationship between the bizygomatic width (distance between the opposite zygomatic processes) of the skull and body length because of the variable rostrum length in modern sperm whales and the rostrum of ''Livyatan'' being proportionally shorter. Doing so produced length estimates of when using the modern sperm whale and when using ''Zygophyseter.'' It has been estimated to weigh based on the length estimate of . By comparison, the modern sperm whale length measures on average for females and for males, with some males reaching up to long. The large size was probably an anti-predator adaptation, and allowed it to feed on larger prey. ''Livyatan'' is the largest fossil sperm whale discovered, and was also one of the biggest-known predators, having the largest bite of any

tetrapod Tetrapods (; ) are four-limb (anatomy), limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant taxon, extant and extinct amphibians, sauropsids (reptiles, including dinosaurs and therefore birds) and synapsids (p ...

.

Skull

The holotype skull of ''Livyatan'' was about long. Like other raptorial sperm whales, ''Livyatan'' had a wide gap in between the temporal fossae on the sides of the skull and the zygomatic processes on the front of the skull, indicating a large space for holding strong temporal muscles, which are the most powerful muscles between the skull and the jaw. The

snout A snout is the protruding portion of an animal's face, consisting of its nose, mouth, and jaw. In many animals, the structure is called a muzzle, rostrum, or proboscis. The wet furless surface around the nostrils of the nose of many mammals is ...

was robust, thick, and relatively short, which allowed it to clamp down harder and better handle struggling prey. The left and right

premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has ...

e on the snout probably did not intersect at the tip of the snout, though the premaxillae took up most of the front end of the snout. Unlike in the modern sperm whale, the premaxillae reached the sides of the snout. The upper jaw was thick, especially midway through the snout. The snout was asymmetrical, with the right

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The ...

in the upper jaw becoming slightly convex towards the back of the snout, and the left maxilla becoming slightly concave towards the back of the snout. The

vomer The vomer (; lat, vomer, lit=ploughshare) is one of the unpaired facial bones of the skull. It is located in the midsagittal line, and articulates with the sphenoid, the ethmoid, the left and right palatine bones, and the left and right maxil ...

reached the tip of the snout, and was slightly concave, decreasing in thickness from the back to the front. A sudden thickening in the middle-left side of the vomer may indicate the location of the nose plug muscles. Each

mandible In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bon ...

in the lower jaw was higher than it was wide, with a larger gap in between the two than in the modern sperm whale. The

mandibular symphysis In human anatomy, the facial skeleton of the skull The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more p ...

which connects the two halves of the mandibles in the middle of the lower jaw was unfused. The condyloid process, which connects the lower jaw to the skull, was located near the bottom of the mandible like other sperm whales.

Teeth

Unlike the modern sperm whale, ''Livyatan'' had functional teeth in both jaws. The wearing on the teeth indicates that the teeth sheared past each other while biting down, meaning it could bite off large portions of flesh from its prey. Also, the teeth were deeply embedded into the gums and could interlock, which were adaptations to holding struggling prey. None of the teeth of the holotype were complete, and none of the back teeth were well-preserved. The lower jaw contained 22 teeth, and the upper jaw contained 18 teeth. Unlike other sperm whales with functional teeth in the upper jaw, none of the

tooth roots Dental anatomy is a field of anatomy dedicated to the study of human tooth structures. The development, appearance, and classification of teeth fall within its purview. (The function of teeth as they contact one another falls elsewhere, under den ...

were entirely present in the

premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has ...

portion of the snout, being at least partially in the maxilla. Consequently, its tooth count was lower than those sperm whales, and, aside from the modern dwarf (''Kogia sima'') and

pygmy In anthropology, pygmy peoples are ethnic groups whose average height is unusually short. The term pygmyism is used to describe the phenotype of endemic short stature (as opposed to disproportionate dwarfism occurring in isolated cases in a pop ...

(''K. breviceps'') sperm whales, it had the lowest tooth count in the lower jaw of any sperm whale. The most robust teeth in ''Livyatan'' were the fourth, fifth, and sixth teeth in each side of the jaw. The well-preserved teeth all had a height greater than , and the largest teeth of the holotype were the second and third on the left lower jaw, which were calculated to be around high. The first right tooth was the smallest at around . The Beaumaris sperm whale tooth measured around in length, and is the largest fossil tooth discovered in Australia. These teeth are thought to be among the largest of any known animal, excluding

tusk Tusks are elongated, continuously growing front teeth that protrude well beyond the mouth of certain mammal species. They are most commonly canine teeth, as with pigs and walruses, or, in the case of elephants, elongated incisors. Tusks share ...

s. Some of the lower teeth have been shown to contain a facet for when the jaws close, which may have been used to properly fit the largest teeth inside the jaw. In the front teeth, the tooth diameter decreased towards the base. This was the opposite for the back teeth, and the biggest diameters for these teeth were around in the lower jaw. All teeth featured a rapid shortening of the diameter towards the tip of the tooth, which were probably in part due to wearing throughout their lifetimes. The curvature of the teeth decreased from front to back, and the lower teeth were more curved at the tips than the upper teeth. The front teeth projected forward at a 45° angle, and, as in other sperm whales, cementum was probably added onto the teeth throughout the animal's lifetime. Livyatan skull

All tooth sockets were cylindrical and single-rooted. The tooth sockets increased in size from the first to the fourth and then decreased, the fourth being the largest at around in diameter in the upper jaws, which is the largest of any known whale species. The tooth sockets were smaller in the lower jaw than they were in the upper jaw, and they were circular in shape, except for the front sockets which were more ovular.

Basin

The fossil skull of ''Livyatan'' had a curved basin, known as the supracranial basin, which was deep and wide. Unlike other raptorial sperm whales, but much like in the modern sperm whale, the basin spanned the entire length of the snout, causing the entire skull to be concave on the top rather than creating a snout as seen in '' Zygophyseter'' and '' Acrophyseter''. The supracranial basin was the deepest and widest over the braincase, and, unlike other raptorial sperm whales, it did not overhang the eye socket. It was defined by high walls on the sides. The antorbital notches, which are usually slit-like notches on the sides of the skull right before the snout, were inside the basin. A slanting crest on the temporal fossa directed towards the back of the skull separated the snout from the rest of the skull, and was defined by a groove starting at the antorbital processes on the cheekbones. The basin had two foramina in the front, as opposed to the modern sperm whale which has one foramen on the maxilla, and to the modern dwarf and pygmy sperm whales which have several in the basin. The suture in the basin between the maxilla and the forehead had an interlocking pattern.

Palaeobiology

Hunting

''Livyatan'' was an

apex predator An apex predator, also known as a top predator, is a predator at the top of a food chain, without natural predators of its own. Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the highest trophic le ...

, and probably had a profound impact on the structuring of Miocene marine communities. Using its large and deeply rooted teeth, it is likely to have hunted large prey near the surface, its diet probably consisting mainly of medium-sized baleen whales ranging from in length. It probably also preyed upon sharks, seals, dolphins, and other large marine vertebrates, occupying a niche similar to the modern

killer whale The orca or killer whale (''Orcinus orca'') is a toothed whale belonging to the oceanic dolphin family, of which it is the largest member. It is the only extant species in the genus '' Orcinus'' and is recognizable by its black-and-white ...

(''Orcinus orca''). It was contemporaneous with and occupied the same region as the otodontid shark '' O. megalodon'', which was likely also an apex predator, implying

competition Competition is a rivalry where two or more parties strive for a common goal which cannot be shared: where one's gain is the other's loss (an example of which is a zero-sum game). Competition can arise between entities such as organisms, ind ...

over their similar food sources. It is assumed that the hunting tactics of ''Livyatan'' for hunting whales were similar to that of the modern killer whale, pursuing prey to wear it out, and then drowning it. Modern killer whales work in groups to isolate and kill whales, but, given its size, ''Livyatan'' may have been able to hunt alone.

Isotopic analysis Isotope analysis is the identification of isotopic signature, abundance of certain stable isotopes of chemical elements within organic and inorganic compounds. Isotopic analysis can be used to understand the flow of energy through a food web, ...

of enamel from a tooth from Chile enamel revealed that this individual likely operated at latitudes south of 40°S. Isotopic analyses of contemporary baleen whales in the same formation show that this ''Livyatan'' was not commonly feeding on them, indicating it probably did not exclusively eat large prey, though it may have targeted baleen whales from higher latitudes.

Spermaceti organ

Sperm whale head anatomy (transverse + sagittal)

The supracranial basin in its head suggests that ''Livyatan'' had a large

spermaceti organ The spermaceti organ is an organ present in the heads of toothed whales of the family Physeteroidea, in particular the sperm whale. This organ contains a waxy liquid called spermaceti and is involved in the generation of sound. Description In ...

, a series of oil and wax reservoirs separated by

connective tissue Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesenchyme derived from the mesoderm the middle embryonic germ layer. Connective tissue ...

. The uses for the spermaceti organ in ''Livyatan'' are unknown. Much like in the modern sperm whale, it could have been used in the process of

biosonar Echolocation, also called bio sonar, is a biological sonar used by several animal species. Echolocating animals emit calls out to the environment and listen to the echoes of those calls that return from various objects near them. They use these ...

to generate sound for locating prey. It is possible that it was also used as a means of acoustic displays, such as for communication purposes between individuals. It may have been used for acoustic stunning, which would have caused the bodily functions of a target animal to shut down from exposure to the intense sounds. Another theory says that the enlarged forehead caused by the presence of the spermaceti organ is used in all sperm whales between males fighting for females during mating season by head-butting each other, including ''Livyatan'' and the modern sperm whale. It may have also been used to ram into prey; if this is the case, in support of this, there have been two reports of modern sperm whales attacking whaling vessels by ramming into them, and the organ is disproportionally larger in male modern sperm whales. An alternate theory is that sperm whales, including ''Livyatan'', can alter the temperature of the wax in the organ to aid in buoyancy. Lowering the temperature increases the density to have it act as a weight for deep-sea diving, and raising the temperature decreases the density to have it pull the whale to the surface.

Palaeoecology

Fossils conclusively identified as ''L. melvillei'' have been found in Peru and Chile. However, additional isolated large sperm whale teeth from other locations including Australia, Argentina, and South Africa have been identified as a species or possible close relative of ''Livyatan''. On the basis of these fossils, it was likely that the distribution of ''Livyatan'' was widespread but restricted to the Southern Hemisphere. The warmer waters around the equator have been known to be a climatic barrier for numerous cetaceans since Neogene times, and a possible hypothesis is that ''Livyatan'' may have been among the cetaceans unable to cross the equatorial barrier. However, due to a poor fossil record of ''Livyatan'',

collecting bias In statistics, sampling bias is a bias in which a sample is collected in such a way that some members of the intended population have a lower or higher sampling probability than others. It results in a biased sample of a population (or non-human fa ...

is another possible explanation. The holotype of ''L. melvillei'' is from the

Tortonian The Tortonian is in the geologic time scale an age or stage of the late Miocene that spans the time between 11.608 ± 0.005 Ma and 7.246 ± 0.005 Ma (million years ago). It follows the Serravallian and is followed by the Messinian. The Tort ...

stage of the Upper

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" ...

9.9–8.9 mya in the Pisco Formation of Peru, which is known for its well-preserved assemblage of marine vertebrates. Among the baleen whales found, the most common was an undescribed species of cetotheriid whale measuring around , and most of the other baleen whales found were roughly the same size. Toothed whale remains found consist of beaked whales (such as '' Messapicetus gregarius''), ancient pontoporiids (such as ''

Brachydelphis ''Brachydelphis'' is a genus of pontoporiid known from the Late Miocene Pisco Formation of Peru and the Bahía Inglesa Formation of Chile. Taxonomy Two species are recognized, ''B. jahuayensis'' and ''B. mazeasi''. ''B. mazeasi'' has a shorten ...

mazeasi''),

oceanic dolphin Oceanic dolphins or Delphinidae are a widely distributed family of dolphins that live in the sea. Close to forty extant species are recognised. They include several big species whose common names contain "whale" rather than "dolphin", such as th ...

s, and the raptorial sperm whale ''Acrophyseter''. All seal remains found represent the earless seals. Also found were large sea turtles such as '' Pacifichelys urbinai'', which points to the development of

seagrass Seagrasses are the only flowering plants which grow in marine environments. There are about 60 species of fully marine seagrasses which belong to four families ( Posidoniaceae, Zosteraceae, Hydrocharitaceae and Cymodoceaceae), all in the ...

es in this area. Partial bones of crocodiles were discovered. Of the seabirds, fragmentary bones of

cormorant Phalacrocoracidae is a family of approximately 40 species of aquatic birds commonly known as cormorants and shags. Several different classifications of the family have been proposed, but in 2021 the IOC adopted a consensus taxonomy of seven ge ...

s and petrels were discovered, as well as two species of boobies. The remains of many cartilaginous fish were discovered in this formation, including more than 3,500 shark teeth, which mainly belonged to the ground sharks, such as requiem sharks and

hammerhead shark The hammerhead sharks are a group of sharks that form the family Sphyrnidae, so named for the unusual and distinctive structure of their heads, which are flattened and laterally extended into a "hammer" shape called a cephalofoil. Most hammerhe ...

s. To a lesser extent, mackerel sharks were also found, such as white sharks,

sand shark Sand sharks, also known as sand tiger sharks, gray nurse sharks or ragged tooth sharks, are mackerel sharks of the family Odontaspididae. They are found worldwide in temperate and tropical waters. The three species are in two genera. Descripti ...

s, and Otodontidae. Many shark teeth were associated with the extinct broad-tooth mako (''Cosmopolitodus/Carcharodon hastalis'') and megalodon, and the teeth of these two sharks were found near whale and seal remains. Eagle rays,

sawfish Sawfish, also known as carpenter sharks, are a family of rays characterized by a long, narrow, flattened rostrum, or nose extension, lined with sharp transverse teeth, arranged in a way that resembles a saw. They are among the largest fish ...

, and angelsharks were other cartilaginous fish found. Most of the

bony fish Osteichthyes (), popularly referred to as the bony fish, is a diverse superclass of fish that have skeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes, which have skeletons primarily composed of cartila ...

findings belonged to

tuna A tuna is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae ( mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary greatly, ranging from the bullet tuna (max le ...

s and croakers. ''Livyatan'' and megalodon were likely the apex predators of this area during this time. ''L. melvillei'' is also known from the

Bahía Inglesa Formation Caldera Basin ( es, Cuenca de Caldera) is a sedimentary basin located in the coast of northern Chile west of Copiapó. The basin has a fill of marine sediments of Late Cenozoic age. With a north-south extension of and an east-west width of t ...

of Chile, whose fossiliferous beds are dated between the Tortonian and

Messinian The Messinian is in the geologic timescale the last age or uppermost stage of the Miocene. It spans the time between 7.246 ± 0.005 Ma and 5.333 ± 0.005 Ma (million years ago). It follows the Tortonian and is followed by the Zanclean, the fir ...

9.03–6.45 mya. Like the Pisco Formation, the Bahía Inglesa Formation famously holds one of the richest marine vertebrate assemblages. Baleen whale remains include ancient

minke whale The minke whale (), or lesser rorqual, is a species complex of baleen whale. The two species of minke whale are the common (or northern) minke whale and the Antarctic (or southern) minke whale. The minke whale was first described by the Danish na ...

s, grey whales,

bowhead whale The bowhead whale (''Balaena mysticetus'') is a species of baleen whale belonging to the family Balaenidae and the only living representative of the genus '' Balaena''. They are the only baleen whale endemic to the Arctic and subarctic waters, ...

s, and cetotheriids. Of the toothed whales, five species of pontoporiids as well as beaked whales,

porpoise Porpoises are a group of fully aquatic marine mammals, all of which are classified under the family Phocoenidae, parvorder Odontoceti (toothed whales). Although similar in appearance to dolphins, they are more closely related to narwhals ...

s, three other species of sperm whales such as ''cf. Scaldicetus'', and the '' Odobenocetops'' have been yielded. Other marine mammals include the marine sloth '' Thalassocnus'' and pinnipeds like ''

Acrophoca ''Acrophoca longirostris'', sometimes called the swan-necked seal, is an extinct genus of Late Miocene pinniped. It was thought to have been the ancestor of the modern leopard seal, however it is now thought to be a species of monk seal. Taxono ...

''. At least 28 different species of sharks have been described, including many extant ground sharks and white sharks as well as extinct species such as the false mako (''Parotodus sp.''), broad-toothed mako, megalodon, and the transitional great white '' Carcharodon hubbelli''. Other marine vertebrates include

penguin Penguins ( order Sphenisciformes , family Spheniscidae ) are a group of aquatic flightless birds. They live almost exclusively in the Southern Hemisphere: only one species, the Galápagos penguin, is found north of the Equator. Highly adapt ...

s and other seabirds, and species of crocodiles and ghavials. The Beaumaris sperm whale was found in the Beaumaris Bay Black Rock Sandstone Formation in Australia near the city of

Melbourne Melbourne ( ; Boonwurrung/ Woiwurrung: ''Narrm'' or ''Naarm'') is the capital and most populous city of the Australian state of Victoria, and the second-most populous city in both Australia and Oceania. Its name generally refers to a me ...

, dating to 5mya in the Pliocene. Beaumaris Bay is one of the most productive marine fossil sites in Australia for marine megafauna. Shark teeth belonging to twenty different species have been discovered there, such as from the

whale shark The whale shark (''Rhincodon typus'') is a slow-moving, filter-feeding carpet shark and the largest known extant fish species. The largest confirmed individual had a length of .McClain CR, Balk MA, Benfield MC, Branch TA, Chen C, Cosgrove J, ...

(''Rhincodon typus''), the Port Jackson shark (''Heterodontus portusjacksoni''), the broad-toothed mako, and megalodon. Some examples of whales found include the ancient humpback whale '' Megaptera miocaena'', the

dolphin A dolphin is an aquatic mammal within the infraorder Cetacea. Dolphin species belong to the families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), Iniidae (the New World river dolphins), Pontoporiidae (t ...

''

Steno cudmorei Steno may refer to: * Steno, Salamis, a small community at the northwest of Salamis Island, Greece * Stenography, the process of writing in shorthand ** Stenotype, a specialized chorded keyboard or typewriter used by stenographers for shorthand ...

'', and the sperm whale '' Physetodon baileyi''. Other large marine animals found include ancient

elephant seal Elephant seals are very large, oceangoing earless seals in the genus ''Mirounga''. Both species, the northern elephant seal (''M. angustirostris'') and the southern elephant seal (''M. leonina''), were hunted to the brink of extinction for oil ...

s,

dugong The dugong (; ''Dugong dugon'') is a marine mammal. It is one of four living species of the order Sirenia, which also includes three species of manatees. It is the only living representative of the once-diverse family Dugongidae; its close ...

s, sea turtles, ancient penguins such as '' Pseudaptenodytes'', the extinct albatross '' Diomedea thyridata'', and the extinct toothed seabirds of the genus '' Pelagornis''. The South African teeth attributed as ''cf. Livyatan'' are from the

Avontuur Member Avontuur is a town situated in the Garden Route District Municipality in the Western Cape province of South Africa. The town is located 13km south-east of Uniondale on an intersection of the R339 and R62 regional routes. History The name is ...

of the Alexander Bay Formation near the village of Hondeklip Bay, Namaqualand, which is also dated to around 5mya in the Pliocene. The Hondeklip Bay locality enjoys a rich heritage of marine fossils, whose diversity may have been thanks to the initiation of the Benguela Upwelling during the late Miocene, which likely provided large populations of phytoplankton traveling the cold nutrient-rich waters. Cetaceans are the most abundant fauna in the bay, although remains tend to be difficult to conclusively identify. Included are three species of balaenopterids including two undetermined species and one identified as ''cf.

Plesiobalaenoptera ''Plesiobalaenoptera'' is a genus of extinct rorqual which existed in Italy during the late Miocene epoch. The type species is ''P. quarantellii''. It is the oldest known rorqual from the Mediterranean basin. Fossils have been found from sediment ...

'', an ancient grey whale (''cf. Eschrichtius sp.''), an undetermined balaenid, an unidentified dolphin, and another undetermined species of macroraptorial sperm whale. Other localities of similar age on the South African west coast have also yielded many additional species of balaenopterids and sperm whales as well as ten species of beaked whales. Large sperm whale teeth of up to around ~ in length are common in Hondeklip Bay, indicating a high presence of large sperm whales like ''Livyatan'' in the area. The locality has also a high presence of sharks indicated by a large abundance of shark teeth; however, most of these teeth have not been identified. Megalodon teeth have been found in the bay, and evidence from bite marks in whale bones indicate the additional presence of the

great white shark The great white shark (''Carcharodon carcharias''), also known as the white shark, white pointer, or simply great white, is a species of large Lamniformes, mackerel shark which can be found in the coastal surface waters of all the major ocean ...

, shortfin mako, and broad-toothed mako. Other marine fauna known in Hondeklip Bay include pinnipeds such as '' Homiphoca capensis'', bony fish, and rays.

Extinction

''Livyatan''-like sperm whales became extinct by the early Pliocene likely due to a cooling trend causing baleen whales to increase in size and decrease in diversity, becoming

coextinct Coextinction and cothreatened refer to the phenomena of the loss or decline of a host species resulting in the loss or endangerment of an other species that depends on it, potentially leading to cascading effects across trophic levels. The term or ...

with the smaller whales they fed on. Their extinction also coincides with the emergence of the killer whale as well as large predatory globicephaline dolphins, possibly acting as an additional stressor to their already collapsing niche.

References

External links

'Sea monster' fossil found in Peru desert
by CNN
Ancient sperm whale's giant head uncovered
from Los Angeles Times (The skull is on display in National History Museum in Lima)
A killer sperm whale
with details on sperm whale evolution ;Videos * * * (a collection of images of discovery) {{Taxonbar, from=Q131759 Miocene mammals of Africa Sperm whales Prehistoric toothed whales Prehistoric cetacean genera Miocene cetaceans Miocene mammals of South America Neogene Peru Fossils of Peru Pisco Formation Fossil taxa described in 2010 Herman Melville