Captive Dall's porpoises often repeatedly ran into the walls of their enclosures, refused food, and exhibited skin sloughing. And if you imagine yourself as a baby porpoise or a baby whale or a baby dolphin, perhaps it’s … Odontocetes possess teeth with cementum cells overlying dentine cells. It came to worldwide attention in the 1970s when it was disclosed for the first time to the public that salmon fishing trawls were killing thousands of Dall’s porpoises and other cetaceans each year by accidentally capturing them in their nets. Incidental mortality caused by the fleet of El Golfo de Santa Clara was estimated to be at around 39 vaquitas per year, which is over 17% of the population size. CS1 maint: multiple names: authors list (, narrow-ridged (or Yangtze) finless porpoise, Convention on the Conservation of Migratory Species of Wild Animals, Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas, Agreement on the Conservation of Cetaceans in the Black Sea, Mediterranean Sea and Contiguous Atlantic Area, International Committee for the Recovery of the Vaquita, 10.1671/0272-4634(2005)025[0655:htanep]2.0.co;2, 10.1671/0272-4634(2000)020[0561:ANFPCD]2.0.CO;2, 10.1671/0272-4634(2008)28[863:ANPCOP]2.0.CO;2, "Natural hybridization between Dall's porpoises (, "The digestive organs of the finless porpoise", "Sound transmission in archaic and modern whales: Anatomical adaptations for underwater hearing", "The Marine Mammal Ear: Specializations for Aquatic Audition and Echolocation", "Functional morphology of the reproductive system in Cetecea", "An account of the dissection of a porpess", "Tab for forskningen: Marsvinet Eigil er død", "Porpoise is 2nd to give birth in captivity", "Porpoise rescued in Horseshoe Bay now a permanent resident of aquarium", "Harbour porpoise Daisy, rescued in 2008, dies at Vancouver Aquarium", "Jack the harbour porpoise dies at Vancouver Aquarium", "Wayback Machine: Dall's Porpoises in Captivity", "Captivity: Last hope for saving the vaquita? A dissection of three Burmeister's porpoises shows that they consume shrimp and euphausiids (krill). Females have mammary glands, but the shape of a newborn calf's mouth does not allow it to obtain a seal around the nipple— instead of the calf sucking milk, the mother squirts milk into the calf's mouth. This may lead to a bubbling out of blood gases, and the animal then dies because the blood vessels become blocked, so-called decompression sickness. Cetaceans are entirely carnivorous, although members of the order Sirenia…, cetaceans (porpoises and dolphins) migrate in the same way, as indicated by population fluctuations within a particular area; but little is known about their distribution and migration.…. Unlike human teeth, which are composed mostly of enamel on the portion of the tooth outside of the gum, whale teeth have cementum outside the gum. hamsun.at. The Dall porpoise is black with a large white patch on each side of the body. During the Middle Ages this animal was considered a royal delicacy. They are, however, more closely related to narwhals and belugas than to the true dolphins. , The porpoise eye is relatively small for its size, yet they do retain a good degree of eyesight. The Baiji Dolphinarium, was established in 1992 at the Institute of Hydrobiology of the Chinese Academy of Sciences in Wuhan which allowing the study of behavioral and biological factors affecting the finless porpoise, specifically breeding biology like seasonal changes in reproductive hormones and breeding behavior. Like other mammals, porpoises have defensive features that help them escape predators. The NMMF is a key partner in VaquitaCPR (Conservation, Protection, & Recovery), a consortium comprised of marine mammal scientists, veterinarians, and biologists from around the world that came together to attempt to save the vaquita porpoise from extinction. a mammal that lives in the sea, swims in groups, and looks similar … The much larger killer whales can porpoise only if the surrounding water is laminar, or at most half turbulent. , Finless porpoises have commonly been kept in Japan, as well as China and Indonesia. The baby porpoise is called a calf, just like whales and dolphins which they are closely related to. Marine mammals that make use of biosonar for orientation and communication are not only hindered by the extra noise, but may race to the surface in panic. This porpoise often ventures up rivers, and has been seen hundreds of miles from the sea. Porpoises produce ultrasonic clicks, which are used for both navigation (echolocation) and social communication. porpoise definition: 1. a mammal that lives in the sea, swims in groups, and looks similar to a dolphin but has a…. Definitely one of the strangest looking marine mammals, the spectacled porpoise (Phocoena dioptrica) is also one of the least well known.Rare photograph of a spectacled porpoise breaching. Whale Trackers – An online documentary series about whales, dolphins and porpoises. Dolphins and porpoises are different. Porpoises are fast swimmers in comparison to seals, which typically cruise at 9–28 km/h (5–15 kn). A porpoise is a marine mammal. , As of 2014, only 505 Yangtze finless porpoises remained in the main section of the Yangtze, with an alarming population density in Ezhou and Zhenjiang. A porpoise is a cetacean, like whales and dolphins, and is definitely a mammal. In the art of this and subsequent periods, porpoises are portrayed … The number of individuals taken each year is in the thousands, although a quota of around 17,000 per year is in effect today making it the largest direct hunt of any cetacean species in the world  and the sustainability of the hunt has been questioned. “They are putting in the right pieces to keep this animal from going extinct,” said Robeck, vice president of conservation research at SeaWorld Parks & Entertainment in Orlando, Florida. Whales and porpoises are also mammals. Flipper movement is continuous. Their escape is prevented by closing off the route to the ocean with other boats or nets. Almost all species have female-biased sexual dimorphism, with the females being larger than the males, although those physical differences are generally small; one exception is Dall's porpoise.. Porpoise cannot move their heads from side to side easily. Both were stranded individuals that only survived a few days after their rescue. The four Phocoena species are primarily fish eaters that usually swim in pairs or small groups along coastlines and occasionally in rivers. It is usually seen in groups of 2 to 20 along the northern rim of the Pacific Ocean, where it eats squid and fish. The porpoise is a mammal.  Harbour porpoises have a very long captive history, with poorly documented attempts as early as the 15th century, and better documented starting in the 1860s and 1870s in London Zoo, the now-closed Brighton Aquarium & Dolphinarium, and a zoo in Germany. Although it is the world's most endangered marine cetacean, the vaquita continues to be caught in small-mesh gillnet fisheries throughout much of its range. All but two were incidental catches in fishing nets or strandings. See more ideas about Porpoise, Cetacean, Marine mammals.  Attempts of rehabilitation seven rescued individuals in 1986 only resulted in three that could be released 6 months later. The porpoise family consists of three genera: Phocoena, Phocoenoides, and Neophocaena. They are gray or black above and white below. While many threatened species decline rate slows after their classification, population decline rates of the porpoise are actually accelerating. The finless porpoises (Neophocaena phocaenoides and N. asiaeorientalis) are small slow-moving inhabitants of coastal waters and rivers along the Indian Ocean and western Pacific Ocean. 3. Nearly half of these died within a month of diseases caught before they were captured or from damage sustained during capture. The porpoise is … ", "Gulf of California Harbor Porpoise / Vaquita / Cochito (, "President of Mexico launches plan to save the vaquita".  It nevertheless referred to the porpoise as a fish, most likely not in the modern-day sense, where it refers to a zoolgical group, but the older reference as simply a creature of the sea (cf.  One of the first anatomical descriptions of the airways of the whales on the basis of a harbor porpoise dates from 1671 by John Ray. Dall's Porpoise is a stocky compact porpoise with small head. Porpoises usually swim about in groups. In Japan, sightings of small pods of them herding sand lance onto shore are common year-round. NOW 50% OFF! Dall’s porpoise as fastest aquatic mammal is a species of porpoise found on the North Pacific. Learn more. Porpoises usually swim... | Meaning, pronunciation, translations and examples The Vaquita (Phocoena sinus), literally “little cow” in Spanish, is a species of porpoise endemic to the northern end of the Gulf of California (Sea of Cortez, Vermilion Sea).  This effect, of course, only occurs in porpoises that dive to great depths, such as Dall's porpoise. Averaging 150 cm (for females) or 140 cm (for males) in length, it is the smallest of all living cetaceans. Porpoises, along with whales and dolphins, are descendants of land-living ungulates (hoofed animals) that first entered the oceans around 50 million years ago (Mya). While population decline tracked from 1994 to 2008 has been pegged at a rate of 6.06% annually, from 2006 to 2012, the porpoise population decreased by more than half. The vaquita nearly became extinct in the twentieth century, due to bycatch in gill nets, with a predicted population of fewer than 100 individuals. Finless porpoises live alone or in small groups and eat crustaceans, fish, and squid.  Five protected natural reserves have been established in areas of the highest population density and mortality rates with measures being taken to ban patrolling and harmful fishing gear in those areas. Members of the family Phocoenidae are related to the oceanic dolphins (family Delphinidae), river dolphins, and other toothed whales of the suborder Odontoceti. Calving takes place entirely under water, with the foetus positioned for tail-first delivery to help prevent drowning. Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree.... dolphins, and porpoises. Porpoise definition is - any of a family (Phocoenidae) of small gregarious toothed whales; especially : a blunt-snouted usually dark gray whale (Phocoena phocoena) of the North Atlantic and North Pacific that typically ranges from 5 to 6 feet (1.5 to 1.8 meters) in length. Corrections? It came to worldwide attention in the 1970s when it was disclosed for the first time to the public that salmon fishing trawls were killing thousands of Dall’s porpoises and other cetaceans each year by accidentally capturing them in their nets. Up until 1984, none lived for more than 14 months. These marine mammals have many things in common. As amended by the Conference of the Parties in 1985, 1988, 1991, 1994, 1997, 1999, 2002, 2005 and 2008", "HELCOM Red List of Baltic Sea species in danger of becoming extinct", "Memorandum of Understanding Concerning the Conservation of the Manatee and Small Cetaceans of Western Africa and Macaronesia", "The Yangtze Finless Porpoise: On an Accelerating Path to Extinction? In porpoise. Almost all Dall's porpoises introduced to aquaria died shortly after, typically within days. Source(s): ... Porpoises, along with whales and dolphins, are descendants of land-living mammals, most likely of the Artiodactyl order. In North America the name is sometimes applied to dolphins. Let us know if you have suggestions to improve this article (requires login). Law enforcement officers saw the aquatic mammals frolicking in the water and chasing each other around when patrolling the lake. Let’s start with what they have in common: both dolphins and porpoises are cetaceans, an order of marine mammal that also includes whales. Porpoises, belonging to the Phocoenidae family, are smaller and stouter, with other anatomical differences.Though both animals are very intelligent, dolphins are deemed to be more social and live in larger, more stable groups. Nothing is known about the diet of the spectacled porpoise. They have a very well defined and triangular dorsal fin, allowing them to steer better in the water. Teeth. It is the smallest known Cetacean (whale, dolphin, or porpoise) alive today, reaching lengths of only 4-5 feet (1.2-1.5 m) and weights of not much more than 100 pounds (45 kg).  His detailed descriptions were assimilated by the Romans, but mixed with a more accurate knowledge of the dolphins, as mentioned by Pliny the Elder in his “Natural history”. First of all, the emitted sound level is reduced when the target range decreases. Another word for porpoise.  As part of an attempt of saving the narrow-ridged (or Yangtze) finless porpoise, several are kept in the Baiji Dolphinarium in China. In order to try to prevent extinction, the Mexican government has created a nature reserve covering the upper part of the Gulf of California and the Colorado River delta.  The captive history is best documented from Denmark where about 100 harbour porpoises have been kept, most in the 1960s and 1970s. There have also been efforts to study porpoise biology to help specialize conservation through captivation breeding. Our harbor porpoise study suggests that besides these two mechanisms, there is a … , As part of last-ditch effort of saving the extremely rare vaquita (the tiny remaining population is rapidly declining because of bycatch in gillnets), there have been attempts of transferring some to captivity. The tail and the dorsal fin is usually tipped withy whitish gray.  Very few have been brought into captivity later, but they have lived considerably longer. The ancient Greeks recognized that cetaceans breathe air, give birth to live young, produce milk, and have hair—all features of mammals. Porpoises use echolocation as their primary sensory system. A porpoise is a sea animal that looks like a large grey fish. In North America the name is sometimes applied to dolphins. ", "The Plan to Rescue a Nearly Extinct Porpoise Goes Terribly Awry", "Update: After death of captured vaquita, conservationists call off rescue effort", "Letter to Japanese Government Regarding Dolphin and Small Whale Hunts", "Vaquita Bycatch in Mexico's Artisanal Gillnet Fisheries: Driving a Small Population to Extinction", "Harbor Porpoise and Fisheries: an Uncertainty Analysis of Incidental Mortality", 10.1890/1051-0761(1998)008[1226:hpafau]2.0.co;2, "America's Favorite Fish Tainted by Porpoise Deaths", "Appendix II of the Convention on the Conservation of Migratory Species of Wild Animals (CMS). It is known that populations in the mouth of the Indus River migrate to the sea from April through October to feed on the annual spawning of prawns. Porpoises are mammals. In … Calves are born with only a thin layer of blubber, but rapidly gains a thick layer from the milk, which has a very high fat content. Finless porpoise population decrease of 69.8% in just a 22-year span from 1976 to 2000.  Soon after the project was abandoned. a sea animal that looks similar to a dolphin and breathes air (porpois, from porcopiscis, from porcus ( PORK) + piscis ).  Most porpoises have slightly flattened eyeballs, enlarged pupils (which shrink as they surface to prevent damage), slightly flattened corneas and a tapetum lucidum; these adaptations allow for large amounts of light to pass through the eye and, therefore, they are able to form a very clear image of the surrounding area. The Inuit in the Arctic hunt harbour porpoises by shooting and drive hunt for Dall's porpoise still takes place in Japan.  Their conservation statuses are either at least concern or data deficient. All mammals sleep, but porpoises cannot afford to become unconscious for long because they may drown. Any of various marine toothed whales of the genus Phocoena and related genera, characteristically having a blunt snout and a triangular dorsal fin. for example star-fish, cuttle-fish, jelly-fish and whale-fish). The platypus is a relatively small, semiaquatic mammal native to Australia. Whales and porpoises are also mammals.  In addition to the few kept in Europe, harbour porpoise were displayed at the Vancouver Aquarium (Canada) until recently. The NMMF is a key partner in VaquitaCPR (Conservation, Protection, & Recovery), a consortium comprised of marine mammal scientists, veterinarians, and biologists from around the world that came together to attempt to save the vaquita porpoise from extinction. )The terms porpoise and dolphin are often used interchangeably. To protect the species, China's Ministry of Agriculture classified the species as being National First Grade Key Protected Wild Animal, the strictest classification by law, meaning it is illegal to bring harm to a porpoise.  Odontocetes send out high frequency clicks from an organ known as a melon. This blubber can help with insulation from the harsh underwater climate, protection to some extent as predators would have a hard time getting through a thick layer of fat, and energy for leaner times.  A majority of factors of this population decline are being driven by the massive growth in Chinese industry since 1990 which caused increased shipping and pollution and ultimately environmental degradation. , The fishing market, historically has always had a porpoise bycatch. A porpoise in the Yangtze river, near Nanjing.  This milk contains high amounts of fat, which aids in the development of blubber; it contains so much fat that it has the consistency of toothpaste. Porpoises are placed either in their own family, Phocoenidae, or with the dolphins in the family Delphinidae. People use the terms dolphins, porpoises, and whales to describe marine mammals belonging to the order Cetacea (from the Greek work ketos, “large sea creature”), and often use them interchangeably. A newly born Yangtze finless porpoise (center) swims with his mother (left) and brother at the Hydrobiology Institute of the Chinese Academy of Sciences. , The military and geologists employ strong sonar and produce an increases in noise in the oceans. Porpoises in each ocean basin are reproductively isolated. Harbor porpoises, a marine mammal resembling dolphins, but in the same family as whales, have made several appearances in Utqiaġvik recently. “It may be too little too late, but what they are doing is unprecedented,” Todd Robeck, author of a recent study into the Yangtze porpoise, said of the effort to save the mammal. Males play no part in rearing calves. It is found only near Japan. dolphins, and porpoises. Averaging 150 cm (4.9 ft) (females) or 140 cm (4.6 ft) (males) in length, it is the smallest of all living cetaceans.Today, the species is on … There are seven extant species of porpoise, all among the smallest of the toothed whales. The vaquita, or cochito (P. sinus), is listed as a critically endangered species by the International Union for Conservation of Nature (IUCN). These animals consistently failed to thrive.  Harbour porpoises from the English Channel were found to have accumulated heavy metals. The calf is dependent for one to two years, and maturity occurs after seven to ten years, all varying between species. However, some have preferences between different kinds of fish, indicating some sort of attachment to taste. Also, like all mammals, dolphins even have a tiny amount of hair, right around the blowhole, which is a little different than the scales of a fish. Porpoises are placed either in their own family, Phocoenidae, or with the dolphins in the family Delphinidae. One of the main ways to tell the difference between a dolphin and a porpoise is from their teeth. very social and playful, they will often “surf” in the bow (front) wake of boats Instead of sound passing through the outer ear to the middle ear, porpoises receive sound through the throat, from which it passes through a low-impedance fat-filled cavity to the inner ear. Their flippers, for example, contain four digits. Also, like all mammals, dolphins even have a tiny amount of hair, right around the blowhole. There are 75 species of dolphins, whales, and porpoises living in the ocean. The finless porpoises (Neophocaena phocaenoides and N. asiaeorientalis) are small slow-moving inhabitants of coastal waters and rivers along the Indian Ocean and western Pacific Ocean.Black above and white below, finless porpoises have a rounded head. Today, the Marine Mammal Protection Act of 1972 has enforced the use of safer fishing equipment to reduce bycatch. Porpoise definition: A porpoise is a sea animal that looks like a large grey fish . Once they’ve moved on, cooler temperate species such as harbor porpoises and seals arrive for the winter and tend to stay until spring. Some species log out of the water, which may allow then to travel faster, and sometimes they porpoise out of the water, meaning jump out of the water. This type of fishery for harbour porpoises is well documented from the Danish Straits, where it occurred regularly until the end of the 19th century, and picked up again during World war I and World War II. Researchers recognize seven different species of these of animals, including the Harbor, Dall’s, Finless, Narrow-Ridged Finless, Spectacled, and Burmeister’s Porpoise, and the Vaquita. Little is known about reproductive behaviour. In contrast to many dolphin species, porpoises do not form large social groups. POP for a Porpoise (Prevent Ocean Plastics) is an educational program presented by the National Marine Mammal Foundation (NMMF) which aims to educate kids about the plastic ocean pollution epidemic. Porpoises range in size from the vaquita, at 1.4 metres (4 feet 7 inches) in length and 54 kilograms (119 pounds) in weight, to the Dall's porpoise, at 2.3 m (7 ft 7 in) and 220 kg (490 lb). / ˈpɔːr.pəs / uk.  Increasing pollution is a serious problem for marine mammals. While they’re both highly intelligent, dolphins are typically more curious around humans than porpoises are. The Vaquita is a small harbor porpoise native to a very small area in the extreme northern part of the Gulf of California, Mexico. In Aristotle's time, the 4th century BCE, porpoises were regarded as fish due to their superficial similarity. To find a porpoise in the bathtub in your home represents negative outside influences. Unlike other porpoises, they lack a dorsal fin entirely. Both species are considered vulnerable; however, the population of the Yangtze finless porpoise (N. asiaeorientalis asiaeorientalis), a subspecies of narrow-ridged finless porpoise found only in the Yangtze River, has declined significantly since 1984. Protective measures in the Tian-e-Zhou Oxbow Nature Reserve has increased its population of porpoises from five to forty in 25 years. noun [ C ] us. A porpoise looks like a fish, but is really a mammal. , Porpoises are not thought to have a good sense of taste, as their taste buds are atrophied or missing altogether. With Less than 10 Left, It’s the Rarest Marine Mammal on Earth . Porpoise, (family Phocoenidae), specifically, any of seven species of toothed whales distinguishable from dolphins by their more compact build, generally smaller size (maximum length about 2 metres, or 6.6 feet), and curved blunt snout with spatulate rather than conical teeth. , The porpoise ear has specific adaptations to the marine environment. Porpoises are in fact often confused with dolphins. 36 sentence examples: 1. the common porpoise of the North Atlantic and Pacific. As of 1986, three establishments in Japan had bred them, and there had been five recorded births. Dall’s porpoises are compact, muscular porpoises that rival killer whales as the fastest marine mammals in Alaska waters. The harbour porpoise was one of the most accessible species for early cetologists, because it could be seen very close to land, inhabiting shallow coastal areas of Europe. Other articles where Common porpoise is discussed: porpoise: …known of these is the harbour porpoise, Phocoena phocoena, a shy cetacean that generally avoids boats and rarely leaps above the water. Porpoises have two flippers on the front, and a tail fin. 2. Dolphins are by far more prevalent than porpoises. Harbor porpoises, a marine mammal resembling dolphins, but in the same family as whales, have made several appearances in Utqiaġvik recently.  CIRVA has worked together with the CITES, the Endangered Species Act, and the Marine Mammal Protection Act (MMPA) to nurse the vaquita population back to a point at which they can sustain themselves. This is a Vaquita. Burmeister’s porpoise (P. spinipinnis) has blunt tubercles on its dorsal fin and lives off the coasts of eastern and western South America.  In addition, the Harbour porpoise is covered by the Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas (ASCOBANS), the Agreement on the Conservation of Cetaceans in the Black Sea, Mediterranean Sea and Contiguous Atlantic Area (ACCOBAMS) and the Memorandum of Understanding Concerning the Conservation of the Manatee and Small Cetaceans of Western Africa and Macaronesia. You have to feed. How to use porpoise in a sentence. The orca, or killer whale, for example, is actually the largest member of the dolphin family. Their stomachs also contained some deep-sea benthic organisms. , Little is known about the diets of other species of porpoises. Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox. Even the 1975 Florida legislature, adopting the creature as the official saltwater mammal, left the issue open, designating the " porpoise, also commonly known as the dolphin," (Tursiops truncates.) And as with the other whales and dolphins, when these animals are born, they have a few little whiskers just around their snout. The Dall porpoise (Phocoenoides dalli) is the largest porpoise and the only member of its genus. Check out our porpoise mammal selection for the very best in unique or custom, handmade pieces from our shops. Even the 1975 Florida legislature, adopting the creature as the official saltwater mammal, left the issue open, designating the "porpoise, also commonly known as the dolphin," (Tursiops truncates. The oldest fossils are known from the shallow seas around the North Pacific, with animals spreading to the European coasts and Southern Hemisphere only much later, during the Pliocene. This melon consists of fat, and the skull of any such creature containing a melon will have a large depression. In the art of this and subsequent periods, porpoises are portrayed with a long snout (typical of dolphins) and a high-arched head. The harbour porpoise (Phocoena phocoena) is one of seven species of porpoise. Similar to the navy, some boats produce waves that attract porpoises, while others may repel them.  The porpoise ear is acoustically isolated from the skull by air-filled sinus pockets, which allow for greater directional hearing underwater. And as with the other whales and dolphins, when these animals are born, they have a few little whiskers just around their snout. , Porpoises eat a wide variety of creatures. By 2020, ecologists had estimated that no more than 18 adults remained. , The olfactory lobes are absent in porpoises, suggesting that they have no sense of smell. They’re further classified as toothed whales along with belugas, narwhals and sperm whales. While knowledge of sleep in wild cetaceans is limited, porpoises in captivity have been recorded to sleep with one side of their brain at a time, so that they may swim, breathe consciously, and avoid both predators and social contact during their period of rest. Several species exhibit sexual dimorphism in that the females are larger than males.  Disregarding one born more than 100 years ago that was the result of a pregnant female being brought into captivity, the world's first full captive breeding was in 2007 in the Fjord & Bælt Centre, followed by another in 2009 in the Dolfinarium Harderwijk, the Netherlands. The Porpoise is a group of marine mammals that are closely related to dolphins. There maybe a challenging time in the future. People use the terms dolphins, porpoises, and whales to describe marine mammals belonging to the order Cetacea (from the Greek work ketos, “large sea creature”), and often use them interchangeably. They are actually a type of dolphin, and belong to the same family as dolphins and whales. “It may be too little too late, but what they are doing is unprecedented,” Todd Robeck, author of a recent study into the Yangtze porpoise, said of the effort to save the mammal. Among the three rescues, one (father of world's first harbour porpoise born in captivity) lived for 20 years in captivity and another 15 years, while the third (mother of first born in captivity) was still alive in 2018 after 20 years. True’s porpoise (P. dalli truei) is considered by some authorities to be a separate subspecies and is distinguished from the Dall porpoise by its absence of the striking white body patches. From the Cambridge English Corpus The arrival of pelagic—mid-water—trawlers also coincides with the washing up of huge numbers of dead dolphins, porpoises and whales. China counted 1,012 Yangtze porpoises in its last census in 2017, down from 2,500 in 1991, and the numbers are falling by about 10% a year, officials said. This helps them to blend into their watery environment. This can help them get away from some predators as well.
2020 is a porpoise a mammal