86-489: Moutohora Island (previously known as Whale Island ) ( Māori : Moutohorā ) is a small uninhabited island located off the Bay of Plenty coast of New Zealand 's North Island , about 9 kilometres (5.6 mi) north of the town of Whakatāne . The 1.43 km (0.55 sq mi) island is a remnant of a complex volcano which has eroded, leaving two peaks. This is still an area of volcanic activity and there are hot springs on
172-479: A V-shaped blow. They are surrounded by a fleshy ridge that keeps water away while the whale breathes. The septum that separates the blowholes has two plugs attached to it, making the blowholes water-tight while the whale dives. Like other mammals, the skin of baleen whales has an epidermis , a dermis , a hypodermis , and connective tissue . The epidermis, the pigmented layer, is 5 millimeters (0.2 in) thick, along with connective tissue. The epidermis itself
258-437: A fiber-reinforced structure made of intermediate filaments (proteins). The degree of calcification varies between species, with the sei whale having 14.5% hydroxyapatite , a mineral that coats teeth and bones, whereas minke whales have 1–4% hydroxyapatite. In most mammals, keratin structures, such as wool , air-dry, but aquatic whales rely on calcium salts to form on the plates to stiffen them. Baleen plates are attached to
344-468: A lunge-feeding behavior. Lunge-feeding is where a whale rams a bait ball (a swarm of small fish ) at high speed. Rorquals generally have streamlined physiques to reduce drag in the water while doing this. Balaenids rely on their huge heads, as opposed to the rorquals' throat pleats, to feed effectively. This feeding behavior allows them to grow very big and bulky, without the necessity for a streamlined body. They have callosities , unlike other whales, with
430-426: A nearly continuous stage of releasing volcanic gas at least since it was sighted by James Cook in 1769. Whakaari erupted continually from December 1975 until September 2000, marking the world's longest historic eruption episode, according to GeoNet , as well as in 2012, 2016, and 2019. The latter of these resulted in 22 deaths and 25 serious injuries, primarily of tourists from a nearby cruise ship who were exploring
516-546: A number of infrasonic vocalizations , notably the songs of the humpback whale . The meat, blubber, baleen, and oil of baleen whales have traditionally been used by the indigenous peoples of the Arctic . Once relentlessly hunted by commercial industries for these products, cetaceans are now protected by international law. These protections have allowed their numbers to recover. However, the North Atlantic right whale
602-422: A number of house terraces and garden sites, middens (food refuse dumps), stone tool manufacture areas and stone walls. After permanent Maori occupation ceased in the early nineteenth century, Ngāti Awa and Tūhoe continued to visit the island for sea food and muttonbirds and to collect stones for hāngī (underground ovens). The first European occupation came in the 1830s with an unsuccessful attempt to establish
688-444: A relatively small brain compared to their body mass . Like other mammals, their brain has a large, folded cerebrum , the part of the brain responsible for memory and processing sensory information. Their cerebrum only makes up about 68% of their brain's weight, as opposed to human's 83%. The cerebellum , the part of the brain responsible for balance and coordination, makes up 18% of their brain's weight, compared to 10% in humans, which
774-485: A sensory organ located in the middle of the jaw to regulate these functions. Baleen whales have two flippers on the front, near the head. Like all mammals, baleen whales breathe air and must surface periodically to do so. Their nostrils, or blowholes , are situated at the top of the cranium . Baleen whales have two blowholes, as opposed to toothed whales which have one. These paired blowholes are longitudinal slits that converge anteriorly and widen posteriorly, which causes
860-605: A shore-based whaling station. The venture failed without a single whale being captured. Forty years later came attempts to make money from sulphur . It was extracted and sold to a refinery in Auckland over a number of years but was of poor quality, and the venture was abandoned in 1895. The next phase of industrial activity came in 1915, when quarrying provided rock for the construction of the Whakatāne harbour wall. A total of 26,000 tonnes (25,589 long tons; 28,660 short tons) of rock
946-439: A spherical lens. The retina is surrounded by a reflective layer of cells ( tapetum lucidum ), which bounces light back at the retina, enhancing eyesight in dark areas. However, light is bent more near the surface of the eye when in air as opposed to water; consequently, they can see much better in the air than in the water. The eyeballs are protected by a thick outer layer to prevent abrasions and an oily fluid (instead of tears) on
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#17327905865171032-644: A translation error in early copies of Aristotle 's Historia Animalium (in Ancient Greek ), in which " ὁ μῦς τὸ κῆτος " ( ho mus to kētos , "the mouse, the whale so called") was mistakenly translated as " ὁ μυστικῆτος " ( ho mustikētos , "the Mysticetus"), which D. W. Rice (of the Society for Marine Mammalogy ) in Rice 1998 assumed was an ironic reference to the animals' great size. An alternate name for
1118-460: A wing-like manner similar to penguins and sea turtles . Flipper movement is continuous. While doing this, baleen whales use their tail fluke to propel themselves forward through vertical motion while using their flippers for steering, much like an otter . Some species leap out of the water, which may allow them to travel faster. Because of their great size, right whales are not flexible or agile like dolphins, and none can move their neck because of
1204-561: Is an archaic word for "whale", which came from Old French baleine , derived from the Latin word balæna , derived itself from the Ancient Greek φάλλαινα (phállaina) . Right whales got their name because of whalers preferring them over other species; they were essentially the "right whale" to catch. Rorquals use throat pleats to expand their mouths, which allow them to feed more effectively. However, rorquals need to build up water pressure in order to expand their mouths, leading to
1290-443: Is defined by 259 kilometres (161 mi) of open coastline used for economic, recreational and cultural purposes. The coastline from Waihi Beach in the west to Opape is defined as sandy coast, while the coast from Opape to Cape Runaway is rocky shore. Sizeable harbours are located at Tauranga, Whakatāne and Ohiwa. Major estuaries include Maketu , Little Waihi, Whakatāne, Waiotahe and Waioeka / Ōtara . Eight major rivers empty into
1376-455: Is disturbed by vibrations, it triggers sensory hairs which send electric current to the brain, where vibrations are processed into sound. Baleen whales have a small, yet functional, vomeronasal organ . This allows baleen whales to detect chemicals and pheromones released by their prey. It is thought that 'tasting' the water is important for finding prey and tracking down other whales. They are believed to have an impaired sense of smell due to
1462-428: Is likely due to climate change which caused seasonally shifting accumulations of plankton in various parts of the world, necessitating travel over long distances, as well as the ability to feed on large baitballs to make such trips worthwhile. A 2017 analysis of body size based on data from the fossil record and modern baleen whales indicates that the evolution of gigantism in baleen whales occurred rather recently, within
1548-501: Is only 1 millimeter (0.04 in) thick. The dermis, the layer underneath the epidermis, is also thin. The hypodermis, containing blubber, is the thickest part of the skin and functions as a means to conserve heat. Right whales have the thickest hypodermis of any cetacean, averaging 51 centimeters (20 in), though, as in all whales, it is thinner around openings (such as the blowhole) and limbs. Blubber may also be used to store energy during times of fasting. The connective tissue between
1634-472: Is probably due to the great degree of control necessary for constantly swimming. Necropsies on the brains of gray whales revealed iron oxide particles, which may allow them to find magnetic north like a compass . Unlike most animals, whales are conscious breathers. All mammals sleep, but whales cannot afford to become unconscious for long because they may drown. They are believed to exhibit unihemispheric slow-wave sleep , in which they sleep with half of
1720-509: Is ranked critically endangered by the International Union for Conservation of Nature . Besides hunting, baleen whales also face threats from marine pollution and ocean acidification . It has been speculated that man-made sonar results in strandings . They have rarely been kept in captivity, and this has only been attempted with juveniles or members of one of the smallest species. Baleen whales are cetaceans classified under
1806-957: Is the breeding colony of grey-faced petrels . Sooty shearwaters , little blue penguins , the threatened New Zealand dotterel and variable oystercatchers also breed on the island. Threatened species which are occasional visitors are the Caspian tern , the North Island kaka and New Zealand falcon . Other species present include common forest birds, captive-bred red crowned parakeets, three lizard species and fur seals . Surrounding areas hosts rich marine ecosystem including cetaceans , oceanic birds, sharks . Most common of cetaceans are smaller species such as common and bottlenose dolphins , pilot whales , and killer whales while larger migratory baleen whales ( southern rights and rorquals ) and toothed whales including beaked whales also appear from time to time. In March 1999 local Ngati Awa and
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#17327905865171892-414: Is the fastest among baleen whales, having been recorded travelling as fast as 10 m/s (36 km/h; 22 mph), and sustaining a speed of 2.5 m/s (9.0 km/h; 5.6 mph) for an extended period. While feeding, the rorqual jaw expands to a volume that can be bigger than the whale itself; to do this, the mouth inflates. The inflation of the mouth causes the cavum ventrale, the throat pleats on
1978-751: Is thought that their size increased with their dependence on baleen. However, the discovery of a skull of the toothed Llanocetus , the second-oldest mysticete, yielded a total length of 8 meters (26 ft), indicating filter feeding was not a driving feature in mysticete evolution. The discovery of Janjucetus and others like it suggests that baleen evolution went through several transitional phases. Species like Mammalodon colliveri had little to no baleen, while later species like Aetiocetus weltoni had both baleen and teeth, suggesting they had limited filter feeding capabilities; later genera like Cetotherium had no teeth in their mouth, meaning they were fully dependent on baleen and could only filter feed. However,
2064-411: Is unknown where this occurred, but it is generally believed that they, like their descendants, followed plankton migrations. These primitive baleen whales had lost their dentition in favor of baleen, and are believed to have lived on a specialized benthic, plankton, or copepod diet like modern baleen whales. Baleen whales experienced their first radiation in the mid-Miocene . It is thought this radiation
2150-518: Is usually reversed, with the males being larger, but the females of all baleen whales are usually five percent larger than males. Sexual dimorphism is also displayed through whale song , notably in humpback whales where the males of the species sing elaborate songs. Male right whales have bigger callosities than female right whales. The males are generally more scarred than females which is thought to be because of aggression during mating season. The unique lungs of baleen whales are built to collapse under
2236-471: The Arctic and Antarctic . Gray whales are specialized for feeding on bottom-dwelling crustaceans . Rorquals are specialized at lunge-feeding, and have a streamlined body to reduce drag while accelerating. Right whales skim-feed, meaning they use their enlarged head to effectively take in a large amount of water and sieve the slow-moving prey. Males typically mate with more than one female ( polygyny ), although
2322-648: The Coromandel Peninsula in the west to Cape Runaway in the east. Called Te Moana-a-Toitehuatahi (the Ocean of Toitehuatahi) in the Māori language after Toi-te-huatahi , an early ancestor, the name 'Bay of Plenty' was bestowed by James Cook in 1769 when he noticed the abundant food supplies at several Māori villages there, in stark contrast to observations he had made earlier in Poverty Bay . The bay
2408-544: The Muséum National d'Histoire Naturelle ) and colleagues suggested that, based on phylogenic criteria, there are four extant genera of rorquals. They recommend that the genus Balaenoptera be limited to the fin whale, have minke whales fall under the genus Pterobalaena , and have Rorqualus contain the Sei whale, Bryde's whale, Eden's whale (and by extension Rice's whale), the blue whale, and Omura's whale. The gray whale
2494-559: The Mātaatua tribes. Early Māori settlement also gave rise to many of the town and city names used today. The first recorded European contact came when James Cook sailed through the Bay of Plenty in 1769. Cook noted the abundance of food supplies, in comparison to Poverty Bay further back along the eastern coast of the North Island. Further reports of European contact are scarce prior to
2580-551: The New Zealand Department of Conservation joined forces to see the fulfilment of a dream. Forty North Island saddleback (tieke) were transferred from Cuvier Island (Repanga), off the coast of the Coromandel Peninsula , to Moutohora. This relocation followed the traditional flight made centuries ago when the Mataatua waka (canoe) was accompanied by two tīeke from Repanga to Whakatāne. This flight followed
2666-531: The Oligocene are the Mammalodontidae ( Mammalodon and Janjucetus ) from Australia . They were small with shortened rostra , and a primitive dental formula ( 3.1.4.3 3.1.4.3 ). In baleen whales, it is thought that enlarged mouths adapted for suction feeding evolved before specializations for bulk filter feeding . In the toothed Oligocene mammalodontid Janjucetus , the symphysis is short and
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2752-560: The fin whale ( B. physalus ), the Sei whale ( B. borealis ), Bryde's whale ( B. brydei ), Eden's whale ( B. edeni ), Rice's whale ( B. ricei ), the blue whale ( B. musculus ), the common minke whale ( B. acutorostrata ), the Antarctic minke whale ( B. bonaerensis ), Omura's whale ( B. omurai ), the humpback whale ( M. novaeangliae ), and the gray whale ( E. robustus ). In a 2012 review of cetacean taxonomy, Alexandre Hassanin (of
2838-434: The parvorder Mysticeti, and consist of four extant families : Balaenidae ( right whales ), Balaenopteridae (rorquals), Eschrichtiidae ( gray whale ) and Cetotheriidae ( pygmy right whale ). Balaenids are distinguished by their enlarged head and thick blubber , while rorquals and gray whales generally have a flat head, long throat pleats, and are more streamlined than Balaenids. Rorquals also tend to be longer than
2924-539: The respiratory tract to hold gas while diving. Doing so may cause serious complications such as embolism . Unlike other mammals, the lungs of baleen whales lack lobes and are more sacculated. Like in humans, the left lung is smaller than the right to make room for the heart. To conserve oxygen, blood is rerouted from pressure-tolerant-tissue to internal organs, and they have a high concentration of myoglobin which allows them to hold their breath longer. The heart of baleen whales functions similarly to other mammals, with
3010-549: The 1950s, as kiwifruit did later. On 5 October 2011, the MV Rena ran aground on the Astrolabe Reef in the bay causing a large oil spill , described as New Zealand's worst ever environmental disaster. A volcanic eruption occurred on Whakaari / White Island at 14:11 on 9 December 2019, which resulted in twenty fatalities and twenty-seven injuries, most suffering severe burns. Forty-seven people were reportedly on
3096-458: The 2018 discovery of the toothless Maiabalaena indicates some lineages evolved toothlessness before baleen. Mystacodon selenensis is the earliest mysticete, dating back to 37 to 33 million years ago ( mya ) in the Late Eocene , and, like other early toothed mysticetes, or "archaeomysticetes", M. selenensis had heterodont dentition used for suction feeding. Archaeomysticetes from
3182-545: The 6 m (20 ft) and 3,000 kg (6,600 lb) pygmy right whale to the 31 m (102 ft) and 190 t (210 short tons) blue whale , the largest known animal to have ever existed. They are sexually dimorphic . Baleen whales can have streamlined or large bodies, depending on the feeding behavior, and two limbs that are modified into flippers . The fin whale is the fastest baleen whale, recorded swimming at 10 m/s (36 km/h; 22 mph). Baleen whales use their baleen plates to filter out food from
3268-430: The 60 to 100 bpm in humans. When diving, their heart rate will drop to 4 to 15 bpm to conserve oxygen. Like toothed whales, they have a dense network of blood vessels ( rete mirabile ) which prevents heat-loss. Like in most mammals, heat is lost in their extremities , so, in baleen whales, warm blood in the arteries is surrounded by veins to prevent heat loss during transport. As well as this, heat inevitably given off by
3354-596: The Antarctic circumpolar current and its effects on global climate patterns is excluded as being causal for the same reason. Gigantism also was preceded by divergence of different mysticete lineages, meaning multiple lineages arrived at large size independently. It is possible the Plio-Pleistocene increase in seasonally intense upwellings , causing high-prey-density zones, led to gigantism. When swimming, baleen whales rely on their flippers for locomotion in
3440-483: The North Atlantic right whale ( E. glacialis ). Cetotheriidae consists of only one living member: the pygmy right whale ( Caperea marginata ). The first descriptions date back to the 1840s of bones and baleen plates resembling a smaller version of the right whale, and was named Balaena marginata . In 1864, it was moved into the genus Caperea after a skull of another specimen was discovered. Six years later,
3526-719: The Tauranga iwi, including at the famous Battle of Gate Pā in 1864. Further conflict with the government arose in 1865 when German missionary Carl Völkner and interpreter James Fulloon were killed by local Māori at Ōpōtiki and Whakatāne, respectively. The ensuing conflict resulted in the confiscation of considerable land from several Bay of Plenty iwi by the government. Confiscation of Māori land deprived local iwi of economic resources (among other things), and also provided land for expanding European settlement. The government established fortified positions, including at Tauranga, Whakatāne and Ōpōtiki. European settlers arrived throughout
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3612-553: The arrival of missionary Samuel Marsden to the Tauranga area in 1814. Bay whaling stations operated in the bay during the 19th century. During the 1820s and 1830s, northern iwi including Ngā Puhi invaded the Bay of Plenty during their campaign throughout the North Island, fighting local Māori tribes in what became known as the Musket Wars . However, the 1830s and 1840s saw increased contact between Bay of Plenty Māori and Europeans through trade, although few Europeans settled in
3698-500: The arteries warms blood in the surrounding veins as it travels back into the core . This is otherwise known as countercurrent exchange . To counteract overheating while in warmer waters, baleen whales reroute blood to the skin to accelerate heat-loss. They have the largest blood corpuscles ( red and white blood cells ) of any mammal, measuring 10 micrometers (4.1 × 10 in) in diameter, as opposed to human's 7.1-micrometer (2.8 × 10 in) blood corpuscles. When sieved from
3784-530: The bay from inland catchments, including the Wairoa , Kaituna , Tarawera , Rangitaiki , Whakatane , Waioeka , Motu and Raukokore rivers. The bay contains numerous islands, notably the active andesite stratovolcano Whakaari / White Island . Whakaari is New Zealand's most active cone volcano , and has been built up by continuous volcanic activity over the past 150,000 years. The nearest mainland towns are Whakatāne and Tauranga . The island has been in
3870-457: The brain while the other half remains active. This behavior was only documented in toothed whales until footage of a humpback whale sleeping (vertically) was shot in 2014. It is largely unknown how baleen whales produce sound because of the lack of a melon and vocal cords . In a 2007 study, it was discovered that the larynx had U-shaped folds which are thought to be similar to vocal cords. They are positioned parallel to air flow, as opposed to
3956-653: The capacity of their throats, allowing them to filter larger volumes of water at once. Gray whales are bottom-feeders, meaning they sift through sand to get their food. They usually turn on their sides, scoop up sediment into their mouths and filter out benthic creatures like amphipods , which leave noticeable marks on their heads. The pygmy right whale is easily confused with minke whales because of their similar characteristics, such as their small size, dark gray tops, light gray bottoms, and light eye patches. Molecular phylogeny suggests Mysticeti split from Odontoceti (toothed whales) between 26 and 17 million years ago between
4042-414: The degree of polygyny varies with the species. Male strategies for reproductive success vary between performing ritual displays ( whale song ) or lek mating . Calves are typically born in the winter and spring months and females bear all the responsibility for raising them. Mothers fast for a relatively long period of time over the period of migration, which varies between species. Baleen whales produce
4128-422: The descendent iwi maintain their traditional homelands ( rohe ) in the region, including Te Whānau-ā-Apanui , Te Whakatōhea , Ngāi Tai , Ngāi Tūhoe , Ngāti Awa , Ngāti Tūwharetoa ki Kawerau, Te Arawa , Ngāi Te Rangi , Ngāti Ranginui and Ngāti Pūkenga . Māori named the bay Te Moana-a-Toitehuatahi (the Ocean of Toitehuatahi), or Te Moana-a-Toi for short, after Toi-te-huatahi , an early ancestor of
4214-565: The drowning of the twin sons of Muriwai, sister of Toroa, the captain of the waka. The two tieke settled briefly on Moutohora before returning to Cuvier Island. Public access to Moutohora is restricted to Department of Conservation concession holders and approved scientific parties. During periods of high fire danger all access may be declined. The current concession holders are the local Maori tribe of Ngati Awa and three Whakatāne based tourist operators - Prosail /Whale Island Kayaking, Diveworks Charters Whale Island Tours and Ngāti Awa Tourism. In
4300-405: The end of the century the population had started to dwindle. But after experimenting with different crops, settlers found success with dairy production. Dairy factories sprang up across the Bay of Plenty in the 1900s, with butter and cheese feeding economic prosperity throughout the early 20th century; local Māori continued to live on the fringe of this prosperity. Timber also became a major export in
4386-430: The end of the mouth. This is probably because they feed on slow or immobile prey, combined with the fact that most sunlight does not pass 9.1 meters (30 ft), and hence they do not need acute vision. A whale's eye is adapted for seeing both in the euphotic and aphotic zones by increasing or decreasing the pupil 's size to prevent damage to the eye. As opposed to land mammals which have a flattened lens , whales have
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#17327905865174472-439: The exception of the bowhead whale. Rorquals have a higher proportion of muscle tissue and tend to be negatively buoyant, whereas right whales have a higher proportion of blubber and are positively buoyant. Gray whales are easily distinguished from the other rorquals by their sleet-gray color, dorsal ridges (knuckles on the back), and their gray-white scars left from parasites. As with the other rorquals, their throat pleats increase
4558-609: The fictional Harry Potter universe , Moutohora is the home of a professional Quidditch team, the Moutohora Macaws . The team players wear robes of red, yellow and blue. The racing video game Redout hosts one of the racing complexes at Moutohora called the Volcano. Bay of Plenty The Bay of Plenty ( Māori : Te Moana-a-Toitehuatahi ) is a large bight along the northern coast of New Zealand 's North Island . It stretches 260 kilometres (160 mi) from
4644-636: The first radiation in the late Oligocene. Eomysticetus and others like it showed no evidence in the skull of echolocation abilities, suggesting they mainly relied on their eyesight for navigation. The eomysticetes had long, flat rostra that lacked teeth and had blowholes located halfway up the dorsal side of the snout. Though the palate is not well-preserved in these specimens, they are thought to have had baleen and been filter feeders. Miocene baleen whales were preyed upon by larger predators like killer sperm whales and megalodon . The lineages of rorquals and right whales split almost 20 mya. It
4730-476: The fused cervical vertebrae ; this sacrifices speed for stability in the water. The hind legs are enclosed inside the body, and are thought to be vestigial organs . However, a 2014 study suggests that the pelvic bone serves as support for whale genitalia . Rorquals, needing to build speed to feed, have several adaptions for reducing drag , including a streamlined body; a small dorsal fin, relative to its size; and lack of external ears or long hair. The fin whale
4816-498: The goats which had been introduced to the island were eradicated, a planting programme began and 12,000 plants covering 45 species are now established. Today Moutohora is covered with a mosaic of pōhutukawa , māhoe , kānuka , bracken and grassland. There are 190 native and 110 introduced plant species. The island is now completely free of the goats, rats , cats and rabbits which previously devastated native plants and animals. The most significant feature of Moutohora's current fauna
4902-433: The hypodermis and muscles allows only limited movement to occur between them. Unlike toothed whales, baleen whales have small hairs on the top of their head, stretching from the tip of the rostrum to the blowhole, and, in right whales, on the chin. Like other marine mammals , they lack sebaceous and sweat glands. The baleen of baleen whales are keratinous plates. They are made of a calcified, hard α-keratin material,
4988-399: The island at the time. Whakaari / White Island is roughly circular, about 2 km (1.2 mi) in diameter, and rises to a height of 321 m (1,053 ft) above sea level. It covers an area of approximately 325 ha (800 acres). The exposed island is only the peak of a much larger submarine volcano , which rises up to 1,600 m (5,249 ft) above the nearby seafloor. Sulphur
5074-737: The island in Sulphur Valley, McEwans Bay, and Sulphur Bay. The Māori name, Moutohorā , is a contracted form of Motutohorā , meaning "Whale Island" or "Captured Whale". The spelling "Moutohorā" (with a macron ) is sometimes also used in English, although the official name of the island omits it. The spelling "Motuhora" is also used. ( Tohorā is the Māori name for the southern right whale .) Numerous archaeological sites of both Māori and European origin have been recorded, including an extensive pa (fortified earthworks) site on Pa Hill and
5160-410: The island when it erupted. A second eruption closely followed the first. Baleen whale Baleen whales ( / b ə ˈ l iː n / ), also known as whalebone whales , are marine mammals of the parvorder Mysticeti in the infraorder Cetacea ( whales , dolphins and porpoises ), which use keratinaceous baleen plates (or "whalebone") in their mouths to sieve planktonic creatures from
5246-428: The lack of the olfactory bulb , but they do have an olfactory tract . Baleen whales have few if any taste buds, suggesting they have lost their sense of taste. They do retain salt-receptor taste-buds suggesting that they can taste saltiness. Most species of baleen whale migrate long distances from high latitude waters during spring and summer months to more tropical waters during winter months. This migration cycle
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#17327905865175332-413: The last 3 million years. Before 4.5 million years ago, few baleen whales exceeded 10 meters (33 ft) in length; the two largest Miocene species were less than 13 m (43 ft) in length. The initial evolution of baleen and filter feeding long preceded the evolution of gigantic body size, indicating the evolution of novel feeding mechanisms did not cause the evolution of gigantism. The formation of
5418-851: The late Oligocene or middle Miocene , but the earliest Mysticeti fossils date to at least 34 million years ago. Their evolutionary link to archaic toothed cetaceans ( Archaeoceti ) remained unknown until the extinct Janjucetus hunderi was discovered in the early 1990s in Victoria, Australia . While, unlike a modern baleen whale, Janjucetus lacked baleen in its jaw, the anatomy shows sufficient similarity to baleen whales. It appears to have had very limited apparent biosonar capabilities. Its jaw contained teeth, with incisors and canines built for stabbing and molars and premolars built for tearing. These early mysticetes were exceedingly small compared to modern baleen whales, with species like Mammalodon measuring no greater than 3 meters (10 ft). It
5504-517: The latter half of the 19th century, establishing settlements in Katikati , Te Puke and the Rangitaiki area. In 1876, settlements were incorporated into counties following the nationwide dissolution of the provincial system. Initial settlements in the region struggled: the climate was ill-suited to sheep farming and the geography was inaccessible, further hindered by a lack of infrastructure. By
5590-1055: The latter. Cetaceans ( whales , dolphins , and porpoises ) and artiodactyls are now classified under the order Cetartiodactyla , often still referred to as Artiodactyla (given that the cetaceans are deeply nested with the artiodactyls). The closest living relatives to baleen whales are toothed whales both from the infraorder Cetacea . Bowhead whale [REDACTED] Southern right whale [REDACTED] North Atlantic right whale [REDACTED] North Pacific right whale [REDACTED] Pygmy right whale [REDACTED] Common minke whale [REDACTED] Southern minke whale [REDACTED] Gray whale [REDACTED] Humpback whale [REDACTED] Fin whale [REDACTED] Blue whale [REDACTED] Omura's whale Eden's whale [REDACTED] Rice's whale [REDACTED] Sei whale [REDACTED] Bryde's whale [REDACTED] Balaenidae consists of two genera: Eubalaena (right whales) and Balaena (the bowhead whale , B. mysticetus ). Balaenidae
5676-406: The lower jaw. The auditory meatus is blocked by connective tissue and an ear plug, which connects to the eardrum . The inner-ear bones are contained in the tympanic bulla , a bony capsule. However, this is attached to the skull, suggesting that vibrations passing through the bone is important. Sinuses may reflect vibrations towards the cochlea . It is known that when the fluid inside the cochlea
5762-435: The major difference being the size. The heart can reach 454 kilograms (1,000 lb), but is still proportional to the whale's size. The muscular wall of the ventricle , which is responsible for pumping blood out of the heart, can be 7.6 to 12.7 centimeters (3 to 5 in) thick. The aorta, an artery , can be 1.9 centimeters (.75 in) thick. Their resting heart rate is 60 to 140 beats per minute (bpm), as opposed to
5848-467: The mouth enlarged, the rostrum is wide, and the edges of the maxillae are thin, indicating an adaptation for suction feeding. The aetiocetid Chonecetus still had teeth, but the presence of a groove on the interior side of each mandible indicates the symphysis was elastic, which would have enabled rotation of each mandible, an initial adaptation for bulk feeding like in modern mysticetes. The first toothless ancestors of baleen whales appeared before
5934-440: The parvorder is "Mystacoceti" (from Greek μύσταξ "mustache" + κῆτος "whale"), which, although obviously more appropriate and occasionally used in the past, has been superseded by "Mysticeti" ( junior synonym ). Mysticetes are also known as baleen whales for their baleen , which they use to sieve plankton and other small organisms from the water. The term "baleen" ( Middle English baleyn, ballayne, ballien, bellane , etc.)
6020-408: The perpendicular vocal cords of terrestrial mammals. These may control air flow and cause vibrations. The walls of the larynx are able to contract which may generate sound with support from the arytenoid cartilages . The muscles surrounding the larynx may expel air rapidly or maintain a constant volume while diving. The eyes of baleen whales are relatively small for their size and are positioned near
6106-400: The pressure instead of resisting the pressure which would damage the lungs, enabling some, like the fin whale, to dive to a depth of −470 meters (−1,540 ft). The whale lungs are very efficient at extracting oxygen from the air, usually 80%, whereas humans only extract 20% of oxygen from inhaled air. Lung volume is relatively low compared to terrestrial mammals because of the inability of
6192-529: The pygmy right whale was classified under the family Neobalaenidae. Despite its name, the pygmy right whale is more genetically similar to rorquals and gray whales than to right whales. A study published in 2012, based on bone structure, moved the pygmy right whale from the family Neobalaenidae to the family Cetotheriidae, making it a living fossil ; Neobalaenidae was demoted to subfamily level as Neobalaeninae. Rorquals consist of three genera ( Balaenoptera , Megaptera , and Eschrichtius ) and 11 species:
6278-585: The region. Missionary activity in the region also increased during this time. In 1853, New Zealand was subdivided into provinces , with the Bay of Plenty incorporated into Auckland Province . Conflict returned to the Bay of Plenty during the 1860s with the New Zealand Wars . Initially this stemmed from Tauranga iwi supporting the Waikato iwi in their conflict with the government. In retaliation, British Crown and government-allied Māori forces attacked
6364-435: The surface of the eye. Baleen whales appear to have limited color vision, as they lack S-cones . The mysticete ear is adapted for hearing underwater, where it can hear sound frequencies as low as 7 Hz and as high as 22 kHz , distinct from odontocetes whose hearing is optimized for ultrasonic frequencies. It is largely unknown how sound is received by baleen whales. Unlike in toothed whales, sound does not pass through
6450-437: The third stomach, where it meets fat-digesting enzymes, and is then mixed with an alkaline liquid to neutralize the acid from the fore-stomach to prevent damage to the intestinal tract . Their intestinal tract is highly adapted to absorb the most nutrients from food; the walls are folded and contain copious blood vessels , allowing for a greater surface area over which digested food and water can be absorbed. Baleen whales get
6536-414: The underside stretching to the navel , to expand, increasing the amount of water that the mouth can store. The mandible is connected to the skull by dense fibers and cartilage ( fibrocartilage ), allowing the jaw to swing open at almost a 90° angle. The mandibular symphysis is also fibrocartilaginous, allowing the jaw to bend which lets in more water. To prevent stretching the mouth too far, rorquals have
6622-410: The upper jaw and are absent in the mid-jaw, forming two separate combs of baleen. The plates decrease in size as they go further back into the jaw; the largest ones are called the "main baleen plates" and the smallest ones are called the "accessory plates". Accessory plates taper off into small hairs. Unlike other whales (and most other mammals), the females are larger than the males. Sexual dimorphism
6708-401: The water by either lunge-feeding or skim-feeding. Baleen whales have fused neck vertebrae , and are unable to turn their heads at all. Baleen whales have two blowholes . Some species are well adapted for diving to great depths. They have a layer of fat, or blubber , under the skin to keep warm in the cold water. Although baleen whales are widespread, most species prefer the colder waters of
6794-434: The water they need from their food; however, the salt content of most of their prey ( invertebrates ) is similar to that of seawater, whereas the salt content of a whale's blood is considerably lower (three times lower) than that of seawater. The whale kidney is adapted to excreting excess salt; however, while producing urine more concentrated than seawater, it wastes a lot of water which must be replaced. Baleen whales have
6880-401: The water, food is swallowed and travels through the esophagus where it enters a three-chambered-stomach. The first compartment is known as the fore-stomach; this is where food gets ground up into an acidic liquid, which is then squirted into the main stomach. Like in humans, the food is mixed with hydrochloric acid and protein-digesting enzymes . Then, the partly digested food is moved into
6966-555: The water. Mysticeti comprises the families Balaenidae ( right and bowhead whales), Balaenopteridae ( rorquals ), Eschrichtiidae (the gray whale ) and Cetotheriidae (the pygmy right whale ). There are currently 16 species of baleen whales. While cetaceans were historically thought to have descended from mesonychians , molecular evidence instead supports them as a clade of even-toed ungulates (Artiodactyla). Baleen whales split from toothed whales (Odontoceti) around 34 million years ago . Baleen whales range in size from
7052-555: Was caused by global climate change and major tectonic activity when Antarctica and Australia separated from each other, creating the Antarctic Circumpolar Current . Balaenopterids grew bigger during this time, with species like Balaenoptera sibbaldina perhaps rivaling the blue whale in terms of size, though other studies disagree that any baleen whale grew that large in the Miocene. The increase in size
7138-526: Was formerly classified in its own family. The two populations, one in the Sea of Okhotsk and Sea of Japan and the other in eastern Pacific are thought to be genetically and physiologically dissimilar. However, there is some discussion as to whether the gray whale should be classified into its own family, or as a rorqual, with recent studies favoring the latter. The taxonomic name "Mysticeti" ( / ˌ m ɪ s t ɪ ˈ s iː t aɪ / ) apparently derives from
7224-519: Was mined on the island until the 1930s. Ten miners were killed in 1914 when part of the crater wall collapsed. The Bay of Plenty has a temperate , maritime climate, with warm, humid summers and mild winters. According to local Māori traditions , the Bay of Plenty was the landing point of several migration canoes that brought Māori settlers to New Zealand. These include the Mātaatua , Nukutere , Tākitimu , Arawa and Tainui canoes. Many of
7310-578: Was removed over five years. The island is not included in the boundaries of a territorial authority council (district council) and the Minister of Local Government is its territorial authority, with support from the Department of Internal Affairs . In 1965 Moutohora was declared as a wildlife refuge, named as Moutohora Wildlife Management Reserve , and the island was bought by the Crown in 1984. Once
7396-572: Was thought to have consisted of only one genus until studies done through the early 2000s reported that bowhead whales and right whales are morphologically (different skull shape) and phylogenically different. According to a study done by H. C. Rosenbaum (of the American Museum of Natural History ) and colleagues, the North Pacific ( E. japonica ) and Southern right ( E. australis ) whales are more closely related to each other than to
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