Mysticetes. Scientist, Science, 20 February). They say that in shape and proportions it is intermediate Let us know if you have suggestions to improve this article (requires login). halfway stage. Whales' relationships with humans are also a focus. The excavation site is now a rocky, mountainous desert, but 50 million years ago, it was located beneath the southern edge of an immense, ancient ocean called the Tethys Sea. One important feature that links extinct organisms such as Pakicetus and Indohyus to cetaceans is: the shape of a bone in the middle ear New mutations: are random with respect to their effects on fitness Modern day cetaceans are thought to have evolved from ______ - grazing hooved land mammals. in the early 1980s, after studying the back part of a Pakicetus skull. Why did the descendants of Pakicetus eventually begin moving into the water and evolving into whales? In 2001, scientists found fossils which confirmed the fact that this mammal lived entirely on the land and never went into the water. Odontocete cetaceans produce echolocation clicks, whistles, cries, chirps, and similar sounds. Top 10 Reasons Why Animals and Plants Go Extinct. [2] It was a wolf-like animal, [3] about 1 metre (3 ft 3 in) to 2 metres (6 ft 7 in) long, [4] and lived in and around water where it ate fish and other small animals. During the early Eocene times, "Imagine your hip bones just started to float off your body that is what that is," he said. According to new dating of fossils from Java, Indonesia, H. erectus persisted in this region until around 108,000 to 117,000 years ago. Thewissen and Hussain say primitive whales were probably amphibians, As previously mentioned, the Pakicetus' upward-facing eye placement was a significant indication of its habitat. The cookie is used to store the user consent for the cookies in the category "Performance". About Acanthostega . Heres how it works. In contrast, the origin of cetaceans, which includes whales, began as four-legged land animals who actively used locomotion and were great runners as a result.[14]. These cookies will be stored in your browser only with your consent. "It's odd to have a big predator in this hoofed plant-eating mammal group," said John Flynn, co-curator of the exhibit, referring to the group to which whales and the now-extinct Andrewsarchus belonged. Pakicetus is a prehistoric cetacean mammal which lived approximately 50 million years ago during the Early Eocene Period. Scientific classifiation: Known locations: Pakistan. It belongs to the even-toed ungulates with the closest living non-cetacean relative being the hippopotamus. This species was the longest-lived relative of our own species, first evolving in Africa around 2 million years ago and then spreading into Asia. Pakicetus was classified as an early cetacean due to characteristic features of the inner ear found only in cetaceans (namely, the large auditory bulla is formed from the ectotympanic bone only). Pakicetus (pictured above) looked nothing like a whale, but it would have felt at home in the water. Odontocetes use high frequency vocalizations for echolocation and bio-sonar. Pakicetus itself spent more time out of the water One of the best-known of all the Devonian tetrapods--the first, lobe-finned fish that climbed up out of the water and onto dry land--Acanthostega nevertheless seems to have represented a dead end in the evolution of early vertebrates, the giveaway being that this creature had eight primitive digits on each of its stubby front flippers, compared to the modern standard of five. Extinction of Plants and Animals. In fact, thanks to the vagaries of the fossilization process, most of what we know about early whale evolution derives from animals discovered on or near the Indian subcontinent; other examples include Ambulocetus (aka the "walking whale") and Indohyus. This is the reason it's much healthier to marry a complete stranger than your first cousin, since, otherwise, you run the risk of "inbreeding" undesirable genetic traits, like susceptibility to fatal diseases. Pakicetus had a long snout; a typical complement of teeth that included incisors, canines, premolars, and molars; a distinct and flexible neck; and a very long and robust tail. the bones surrounding the inner and middle ears fit into the other bones It looks like a dog-like animal that if it was still alive, would run up to you and lick your hand. The Marine Reptiles of The Late Cretaceous, Lived around the shores of what is now India and Pakistan. Analytical cookies are used to understand how visitors interact with the website. Pakicetus is a genus of extinct terrestrial carnivorous mammal of the family Pakicetidae which was endemic to Pakistan from the Eocene (55.8 0.240 0.1 million years ago). seal, it probably needed to return to the shore to breed. It thus lacked the fat pad, and sounds reached its eardrum following the external auditory meatus as in terrestrial mammals. Vibrations 2009 argued that "the orbits of these cetaceans were located close together on top of the skull, as is common in aquatic animals that live in water but look at emerged objects. 04. Witness the crisis currently facing the world's amphibians, which are falling prey to chytridiomycosis, a fungal infection that ravages the skin of frogs, toads, and salamanders, and causes death within a few weeks, not to mention the Black Death that wiped out a third of Europe's population during the Middle Ages. their amplitude much smaller. of the eardrum caused by sound waves are transmitted across the air-filled Either well-known The exhibit addresses the whaling industry, modern dangers, such as ship collisions, as well as coastal peoples' interactions with them. [3] The redescription of the primitive, semi-aquatic small deer-like artiodactyl Indohyus, and the discovery of its cetacean-like inner ear, simultaneously put an end to the idea that whales were descended from mesonychids, while demonstrating that Pakicetus, and all other cetaceans, are artiodactyls. Until the early 1800s, billions of passenger pigeons darkened the skies of the United States in spectacular migratory flocks. Pakicetus (Pakistan whale). If a plant or animal from one ecosystem is inadvertently transplanted into another (usually by an unwitting human or an animal host), it can reproduce wildly, resulting in the extermination of the native population. Omissions? [4], The first fossil found consisted of an incomplete skull with a skull cap and a broken mandible with some teeth. (It was modified by the American Museum of Natural History.) According to the location of fossil findings, the animals preferred a shallow habitat that neighbored decent-sized land. world of prehistory is constantly changing with the advent of new which flourished throughout the Eocene epoch. Even more so, however, was its auditory abilities. Evolution: Education and Outreach 2 (2): 272288. NEW YORK By moving into the water full-time, the ancestors of whales paved the way for their descendants to become behemoths, largely free from gravity's constraints. Why Did the Saber-Tooth Tiger (Smilodon) Go Extinct?With their enormous, deadly-sharp canines, saber-toothed carnivores are well known to many people as frig. They may hunt cooperatively either during the day or night, depending on the species. Perhaps because even trained scientists have a hard time accepting a fully terrestrial mammal as the ancestor of all whales, for a while after its discovery in 1983, Pakicetus was described as having a semi-aquatic lifestyle. The first fossil, a skull fragment of P. inachus, was found in 1981 in Pakistan. Their hips and legs were on the way out. Still, this reverse pattern accounts for some 100 living mammal species that inhabit the oceans today, from three major groups. attocki , P. calcis, P. chittas. formed from very hard, dense material and are almost completely surrounded Species: P. inachus (type), David Polly is a vertebrate paleontologist at Indiana University-Bloomington and a Research Associate at the Field Museum in Chicago. She has a masters in journalism from Columbia University and a bachelor's degree in biology from the University of Utah. This is the first thing most people associate with the word "extinction," and not without reason, since we all know that a meteor impact on the Yucatn Peninsula in Mexico caused the disappearance of the dinosaurs 65 million years ago. Over time, fossils also revealed that Pakicetus had an ear bone with a feature unique to whales and an ankle bone that linked it to artiodactyls, a large order of even-toed hoofed mammals that includes hippos, pigs, sheep, cows, deer, giraffes, antelopes, and even cetaceans, the only aquatic artiodactyls. As far as paleontologists can tell, this was the earliest of all the prehistoric whales, a tiny, terrestrial, four-footed mammal that ventured only occasionally into the water to nab fish. The "first whale," a creature whose lifestyle (living on land but eating fish from the nearby sea) represented the early stage of this transition into the water, was a wolf-size fish eater that lived about 50 million years ago on the edges of the ancient Tethys Sea, according to the exhibit. be found on their respective pages; 1 -. The fossils were found in the Kuldana Formation in Kohat in northern Pakistan and were dated as early to early-middle Eocene in age. They are thought to derive from a group Time period: Ypresian to early Bartonian of the Evidence suggests an asteroid impact was the main culprit. The earliest known member of the Odontoceti, the modern toothed whales, is from the early Oligocene, around 30 million years ago. These spherules are believed to have come from the impact itself. Pakicetus is a species of early whale that has only been known since the eighties. Dinopedia is a FANDOM Lifestyle Community. Anatomists going back to 19th century Britain knew that whales were mammals and probably most closely related to. For instance, the skeleton of a pygmy right whale hanging from the ceiling displayed two tiny bones, the remnant of the pelvis, Flynn pointed out. Hopkins studies the changes in trilobite body shape and size over time, and how these factors . copy the articles word for word and claim them as your own work. For example, imagine that scientists find a way to permanently eliminate malaria by exterminating every mosquito on Earth. The discovery of a more complete skeleton in 2001 prompted a reconsideration, and today Pakicetus is deemed to have been fully terrestrial; in the words of one paleontologist, "no more amphibious than a tapir." Anatomy: Dorudon, along with other basilosaurids, differed from all modern cetaceans in the shape of its head and teeth. It does not store any personal data. Diet: Carnivore. the water after fish. In this scenario it could have focused its NASA warns of 3 skyscraper-sized asteroids headed toward Earth this week. They share with Indohyus the signature whale ear and unusually heavy bonesadaptations suggesting a lifestyle that was at least partially aquatic. Is there a database for insurance claims? cover a lot of ground to find food, and the rising and falling tides Chitta Hills of Pakistan. attention upon prey that had become trapped in tidal pools at low Classification: Chordata, Mammalia, Cetacea, New York, "This peculiarity could indicate that Pakicetus could stand in water, almost totally immersed, without losing visual contact with the air."[9]. She has interned at Discover magazine and has freelanced for The New York Times and Scientific American's web site. What did the first whales look like? Pakicetus is one of the earliest whales and the first cetacean discovered with functional legs. Transitional forms. Most archaeocetes (first cetaceans) lived in the Tethys or along its margins. NewDinosaurs.com, 2023. The Archaeocetes were probably Eocene. Its name means Pakistan whale.. www.prehistoric-wildlife.com. Here's where we risk succumbing to a dangerous tautology: By definition, "better-adapted" populations always win out over those that lag behind, and we often don't know exactly what the favorable adaptation was until after the event. Pakicetus, extinct genus of early cetacean mammals known from fossils discovered in 48.5-million-year-old river delta deposits in present-day Pakistan. Whats more, its eyes, positioned close together on top of the skull, would have allowed Pakicetus to see above water even when submerged. The closest living relatives of dolphins today are the even toed ungulates such as camels and cows with the humble hippopotamus being the closest living relative. Thus the hearing mechanism of Pakicetus is the only known intermediate between that of land mammals and aquatic cetaceans. - Origin Of Underwater Hearing In Whales - Nature 361 (6411): 444445. There's no denying, though, that we've wreaked plenty of ecological havoc during our brief time in the spotlight: hunting the starved, straggling megafauna mammals of the last Ice Age; depleting entire populations of whales and other marine mammals; and eliminating the dodo bird and the passenger pigeon virtually overnight. incus of Pakicetus. partial remains. Mass starvation is the quick, one-way, surefire route to extinctionespecially since hunger-weakened populations are much more prone to disease and predationand the effect on the food chain can be disastrous. Length: This website uses cookies to improve your experience while you navigate through the website. (Image credit: Museum of New Zealand Te Papa Tongarewa, 2008). Chemical information from some of these wolf-sized meat-eaters show that they ate fish. It was first discovered in Pakistan and was named by Philip Gingerich and Donald Russell in 1981. "Top 10 Reasons Why Animals and Plants Go Extinct." However, that is exactly what it was. Wynne was a reporter at The Stamford Advocate. Pakicetus inachus [Holotype}Pakicetus inachusPakicetus attockiPakicetus calcisPakicetus chittas. of extinct land-based ungulate mammals called the mesonychid condylarths, Nowadays, there are two varieties of whale. Paleontologists know this because its ears were only adapted for the land and not for the water. Pakicetus is an extinct genus of amphibious cetacean of the family Pakicetidae, which was endemic to Pakistan during the Eocene, about 50 million years ago. ThoughtCo. These leftovers from land are still visible in some modern whales. - From Land to Water: the Origin of Whales, Dolphins, and Porpoises - If you happened to stumble across the small, dog-sized Pakicetus 50 million years ago, you'd never have guessed that its descendants would one day include giant sperm whales and gray whales. Facts About the Ambulocetus Prehistoric Whale, The Dinosaurs and Prehistoric Animals of North Carolina, The Dinosaurs and Prehistoric Animals of South Carolina. are therefore ungulates, especially the even-toed forms pigs, cattle, the skull has brought the second hunting theory of lurking in the water Witness the crisis currently facing the world's amphibians, which are falling prey to chytridiomycosis, a fungal infection that ravages the skin of frogs, toads,and salamanders, and causes death within a few weeks, not to mention the Black Death that wiped out a third of Europe's population during the Middle Ages. The whales massive bulbous head is about one-third of the animals length. First off, whales and dogs have early on ancestors that shared similar traits. Pakicetus is a genus of extinct terrestrial carnivorous mammal of the family Pakicetidae which was endemic to Pakistan from the Eocene (55.8 0.240 0.1 million years ago). bones of the skull. In 2001, scientists found fossils which confirmed the fact that this mammal lived entirely on the land and never went into the water. You also have the option to opt-out of these cookies. Performance cookies are used to understand and analyze the key performance indexes of the website which helps in delivering a better user experience for the visitors. Functional cookies help to perform certain functionalities like sharing the content of the website on social media platforms, collect feedbacks, and other third-party features. Fossils or organisms that show the intermediate states between an ancestral form and that of its descendants are referred to as transitional forms. After the asteroid hit the Earth, it sent a shower of molten rock into the atmosphere, which then crystallized at high altitudes.. But the new discovery suggests that our species. (In the case of narwhals, one tooth becomes a modified tusk.). 1981. The descendants of Dorudon went on to evolve into modern whales. Because of the tooth wear, Pakicetus is thought to have eaten fish and other small animals. all mammals, the ossicles are jointed and form a lever system. - New middle Eocene archaeocetes (Cetacea: Mammalia) from the Kuldana Donald Russell and their colleagues came to broadly the same conclusion by cavities filled with a fine bubbly foam. (2020, August 27). In this scenario it could have focused its attention upon prey that had become trapped in tidal pools at low "[10] With both the auditory and visual senses in mind, as well as the typical diet of Pakicetus, one might assume that the creature was able to attack both aquatic and terrestrial prey from a low vantage point. They originated in Asia and came into North America. Thewissen and Hussain examined a small ear bone or ossicle called the The animal was given the name Pakicetus. Once a species starts dwindling in numbers, there's a smaller pool of available mates and often a corresponding lack of genetic diversity. - J. G. M. Thewissen & S. T. Hussain - 1993. When you purchase through links on our site, we may earn an affiliate commission. [16], Last edited on 26 February 2023, at 14:47, "A new Eocene archaeocete (Mammalia, Cetacea) from India and the time of origin of whales", "Fossil Evidence for the Origin of Aquatic Locomotion in Archaeocete Whales", "A life spent chasing down how whales evolved", "Origin of Whales in Epicontinental Remnant Seas: New Evidence from the Early Eocene of Pakistan", 10.1666/0094-8373(2003)029<0429:LTIEWE>2.0.CO;2, "Skeletons of terrestrial cetaceans and the relationship of whales to artiodactyls", "From Land to Water: the Origin of Whales, Dolphins, and Porpoises", https://en.wikipedia.org/w/index.php?title=Pakicetus&oldid=1141735500, This page was last edited on 26 February 2023, at 14:47. It is the most ancient of presently-known direct ancestors of modern-day whales that lived approximately 48 mln years ago and adjusted to . like a crocodile. "Top 10 Reasons Why Animals and Plants Go Extinct." More information on these whales can Advertisement cookies are used to provide visitors with relevant ads and marketing campaigns. way it may be that these marine adaptations are not just driven by Pakicetus is one of the earliest whales and the first cetacean discovered with functional legs. of the chain of three ossicles in the middle-ear cavity is at a similar The fossils came out of red terrigenous sediments bounded largely by shallow marine deposits typical of coastal environments caused by the Tethys Ocean. Its also a massive sound generator that helps the whale navigate. About 34 million years ago, a group of whales began to develop a new way of eating. Graduated from ENSAT (national agronomic school of Toulouse) in plant sciences in 2018, I pursued a CIFRE doctorate under contract with SunAgri and INRAE in Avignon between 2019 and 2022. Which is Clapeyron and Clausius equation. The information here is completely Cookies collect information about your preferences and your devices and are used to make the site work as you expect it to, to understand how you interact with the site, and to show advertisements that are targeted to your interests. primitive and clearly not fully adapted to life in water. By most reckonings, since the beginning of life on Earth, a whopping 99.9% of all species have gone extinct. Ancient volcanic eruptions didn't play a role in the mass extinction that killed off the dinosaurs, a new study says, putting the blame solely back on an asteroid that slammed into Earth. 2001 wrote that "Pakicetids were terrestrial mammals, no more amphibious than a tapir. The older theory is that the evolution was of whales, and they came from ancestors of hoofed land animals that were very similar to wolves and even-toed ungulates. Strauss, Bob. I am currently continuing at SunAgri as an R&D engineer. Sensory Abilities: Pakicetus had a dense and thickened auditory bulla, which is a characteristic of all cetaceans. Although they had nothing to ponder but this skull, scientists could see that Pakicetus had teeth resembling those of mesonychids, but it was well. - Journal of Vertebrate Paleontology This, of course, was the disaster that wiped out the . Pakicetus attocki . To cite just one example: Because of their extreme habitat loss, today's dwindling population of African cheetahs suffers from unusually low genetic diversity and, thus, may lack the resiliency to survive another major environmental disruption. The ossicles in whales are arranged differently or Odontoceti, and the filter-feeding baleen whales, or Mysticeti. Our editors will review what youve submitted and determine whether to revise the article. The had ears The later descendants of Pakicetus were fully aquatic. Pakicetus has been envisioned by some as a wolf sized predator that would dive into the water after fish. low tide. Whales are mammals, like humans, and their ancestors once lived on land. The exhibitis on display until Jan. 5, 2014. Contributions from the Museum of Paleontology, The Museum of Michigan L. N. Cooper, J. C. George & S. Bajpai - 2009. Volcanic eruptions that caused large-scale climate change may also have been involved, together with more gradual changes to Earth's climate that happened over millions of years. Why did the dinosaurs go extinct? Whatever the causes, the huge extinction that ended the age of the dinosaur left gaps in ecosystems around . His current research is on trait-based community dynamics in vertebrates, 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. aquatic lifestyle. point for your own research. Until further evidence is found, paleontologists are unlikely to be able to answer these questions. also indicate a close relationship between artiodactyls and cetaceans (New Retrieved from https://www.thoughtco.com/pakicetus-pakistan-whale-1093256. ear. represent the group of Why Did Crocodiles Survive the K/T Extinction? The teeth also suggest that Pakicetus had herbivorous and omnivorous ancestors. whales, Pakicetus had not yet severed all links with the land. When you visit the site, Dotdash Meredith and its partners may store or retrieve information on your browser, mostly in the form of cookies. These bristly baleen plates filter, sift, sieve or trap the whales favourite prey from seawater inside their mouths. so the left and right auditory regions were not isolated from each other, Area: But even before the move, this lineage was setting size records. 1906 Dorudon was discovered in 1906 by Charles William Andrews, who described Prozeuglodon atrox (=Proto-Basilosaurus) based on a nearly complete skull, a dentary, and three associated vertebrae presented to him by the Geological Museum of Cairo. We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. An adult blue whale can grow to a massive 30m long and weigh more than 180,000kg thats about the same as 40 elephants, 30 Tyrannosaurus Rex or 2,670 average-sized men. to its transitional nature, it is hard to say with certainty how In addition, it still retained many other features of terrestrial mammals, including an auditory system that was better for hearing in air than in water, a dentition not unlike that of its closest terrestrial relatives, such as the mesonychids, and functional feet capable of locomotion on land. in North Carolina and S. Hussain of Howard University, Washington DC, have In water, the pressure of sound waves is much greater than in air and The large tail of Pakicetus is possibly a specialization for aquatic locomotion, although exactly how is unclear. Strauss, Bob. First discovered by paleontologists in 1983, Pakicetus lived along the margins of a large shallow ocean, the Tethys Sea. Only time will tell. Kevin Guertin/Wikimedia Commons/CC BY 2.0. Asia, Pakistan For example, The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". We also use third-party cookies that help us analyze and understand how you use this website. with other animals such as Ambulocetus, It's likely that many of the Earth's mass extinctionsnot only the K-T extinction, but also the much more severe Permian-Triassic extinctionwere caused by such impact events, and astronomers are constantly on the lookout for comets or meteors that could spell the end of human civilization. Pakicetus, the oldest and most primitive whale The vast majority of paleontologists regard it as the most basal whale, representing a transitional stage between land mammals and whales. adaptation in animals that spend a lot of time in the water. This Pakicetus is an extinct genus of amphibious cetacean of the family Pakicetidae, which was endemic to Pakistan during the Eocene. Pakicetus is an extinct genus of amphibious cetacean of the family Pakicetidae, which was endemic to Pakistan during the Eocene. The Mysticeti include the baleen whales and their extinct relatives. https://www.britannica.com/animal/Pakicetus, New York Institute of Technology - College of Osteopathic Medicine - Cetacean Family Tree - Pakicetus App. The Diet: the air. Other forms such as the aforementioned Ambulocetus been envisioned by some as a wolf sized predator that would dive into [Top 10 Useless Limbs]. When the landmass was eventually lifted back up it brought with it a bounty of marine sediments . The body mass of Pakicetus was estimated at 45 kg (100 pounds), roughly the size of a wolf or large dog. Description This four-footed land mammal named Pakicetus, living some 50 million years ago in what we know as Pakistan today, bears the title of "first whale." By Victoria Jaggard. It certainly doesnt look like the start of some of the largest aquatic mammals ever to live on Earth. During the Miocene (5-23 Ma), modern mysticetes diversified. Pakicetus also exhibited characteristics of its anatomy that link it to modern cetaceans, a group made up of whales, porpoises, and dolphins. Exactly what makes New Zealand prime giant penguin territory has to do with the 'missing' continent Zealandia. 'Building blocks of life' recovered from asteroid Ryugu are older than the solar system itself, Ancient Roman 'spike defenses' made famous by Julius Caesar found in Germany, Otherworldly 'fairy lantern' plant, presumed extinct, emerges from forest floor in Japan, Watch footage of 1,000 baleen whales in record-breaking feeding frenzy in Antarctica, New Moai statue that 'deified ancestors' found on Easter Island, Lab-grown minibrains will be used as 'biological hardware' to create new biocomputers, scientists propose, The ultimate action-packed science and technology magazine bursting with exciting information about the universe, Subscribe today and save an extra 5% with checkout code 'LOVE5', Engaging articles, amazing illustrations & exclusive interviews, Issues delivered straight to your door or device. Paleontologists know this because its ears were only adapted for the land and not for the water. Thats because it doesnt look aquatic at all. Named By: Gingerich & Russell - 1981. Size: Between 1 and 2 meters long. These are called baleen whales, which include blue whales and humpback whales. developed for hearing in predatory forces but practical ones too. Pakicetus A typical representative: Pakicetus inachus Gingerich & Russell, 1981. And we all know about the long-term threat global warming presents to modern civilization. The groups are cetaceans within Artiodactyla, as noted; Carnivora, specifically seals, sea lions, and walruses (the pinnipeds) and an independent invasion of the oceans by sea otters; and Sirenia, which includes several species of aquatic manatees and dugongswhich live in rivers and shallow coastal waters and eat mainly seagrasses. Phonetic: Pa-kee-see-tuss. This cookie is set by GDPR Cookie Consent plugin. But there were other species of megafauna that roam the landscape as well, like giant condors, saber toothed cats and even giant sloths. Thus, Pakicetus represents a transitional taxon between extinct land mammals and modern cetaceans. It was a mammal that would only go near the water to grab fish. Many toothed whales live in large groups and have feeding routines. Commercial Photography: How To Get The Right Shots And Be Successful, Nikon Coolpix P510 Review: Helps You Take Cool Snaps, 15 Tips, Tricks and Shortcuts for your Android Marshmallow, Technological Advancements: How Technology Has Changed Our Lives (In A Bad Way), 15 Tips, Tricks and Shortcuts for your Android Lollipop, Awe-Inspiring Android Apps Fabulous Five, IM Graphics Plugin Review: You Dont Need A Graphic Designer, 20 Best free fitness apps for Android devices. Paleontologists know this because its ears were only adapted for the land and not for the water. Modern whales evolved from archaic whales such as basilosaurids, which in turn evolved from something like the amphibious ambulocetids, which themselves evolved from . However, they do know this is exactly what happened.