what did pakicetus eat

What did the pakicetids eat?

Most likely, pakicetids lived in or near bodies of freshwater and their diet could have included both land animals and aquatic organisms. During the Eocene, Pakistan was a coastal region of the Eurasian land mass and therefore an ideal habitat for the evolution, and diversification of the Pakicetids.

What are some interesting facts about Pakicetus?

One of the most interesting facts about Pakicetus is that according to scientists, this is the earliest whale they’ve found as of yet. It was a mammal that would only go near the water to grab fish. Paleontologists know this because its ears were only adapted for the land and not for the water.

What kind of teeth does Pakicetus have?

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. As in most land mammals, the nose was situated at the tip of the snout.

Were the later descendants of Pakicetus fully aquatic?

The later descendants of Pakicetus were fully aquatic. Modern whales are descended from the archaeocete basilosaurids, a group of toothed whales that had extremely long bodies and tails. The archaeocete basilosaurids appeared later in the Eocene and early Oligocene (34 million to 23 million years ago) and lived in...

What did Pakicetus drink?

'Pakicetus drank fresh water, which is no surprise because all land animals drink fresh water and many mammals cannot survive without a fresh-water source,' said Thewissen, assistant professor of anatomy.

Is a Pakicetus carnivorous?

Pakicetus is a genus of extinct terrestrial carnivorous mammal of the family Pakicetidae which was endemic to Pakistan from the Eocene (55.8 ± 0.2—40 ± 0.1 million years ago). Pakicetus existed for approximately 15.8 million years.

How long did Pakicetus live?

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....Pakicetus.Pakicetus Temporal range: Eocene (Ypresian),Order:ArtiodactylaInfraorder:CetaceaFamily:†PakicetidaeGenus:†Pakicetus Gingerich & Russell 198110 more rows

Did Pakicetus live in fresh water?

What did the first whales look like? Pakicetus (pictured above) looked nothing like a whale, but it would have felt at home in the water. It lived on land, on the edge of lakes and riverbanks in what is now Pakistan and India. It hunted small land animals and freshwater fish, and could even hear underwater.

Why did Pakicetus enter the water?

It was a mammal that would only go near the water to grab fish. Paleontologists know this because its ears were only adapted for the land and not for the water. In 2001, scientists found fossils which confirmed the fact that this mammal lived entirely on the land and never went into the water.

What do whales eat?

They love to eat krill, fish, zooplankton, phytoplankton, and algae. Some, such as the right whale, are called “skimmers”. These whales swim slowly with their huge mouths open to take in large amounts of water and food.

What did Pakicetus evolve?

whalesPakicetus was a shore-dwelling creature with webbed feet that lived around 49 million years ago. Scientists were able to link Pakicetus to the evolutionary lineage of whales because of its distinct, dense ear bones.

Did whales evolved from Pakicetus?

50 million years ago: land-roaming whales The ancestor of today's whales, the first cetacean, is believed to be Pakicetus, a quadruped measuring 1 to 2 metres long. Skeletons discovered in Pakistan indicate that the animal had typical artiodactyl ankles and a typical cetacean skull.

What adaptations did Pakicetus to help it survive in its environment?

They share with Indohyus the signature whale ear and unusually heavy bones—adaptations suggesting a lifestyle that was at least partially aquatic. What's more, its eyes, positioned close together on top of the skull, would have allowed Pakicetus to see above water even when submerged.

Did a Pakicetus have limbs?

Anatomy: Pakicetus looked very different from modern cetaceans, and its body shape more resembled those of land dwelling, hoofed mammals. Unlike all modern and possibly all other fossil cetaceans, it had four fully functional, long legs.

Why did whales lose their legs?

In findings to be published this week in the Proceedings of the National Academy of Sciences, scientists say the gradual shrinkage of the whales' hind limbs over 15 million years was the result of slowly accumulated genetic changes that influenced the size of the limbs and that these changes happened sometime late in ...

How long can a whale live out of water?

If they ever are on land, they can survive only a couple hours. If there is a way of cooling down the whale when it is on land, like pouring cold water onto it, it can survive for a couple hours longer. A lot of whale die when then are on land because they cannot support their own weight when out of the water.

What is Pakicetus made of?

Pakicetus also exhibited characteristics of its anatomy that link it to modern cetaceans, a group made up of whales, porpoises, and dolphins. A resin cast of Pakicetus, based on fossils found in Pakistan, was displayed in the special exhibition Whales: Giants of the Deep. See skeletons of early whales cast from fossils in Whales: Giants of the Deep.

What animal has a long skull?

Although it had the body of a land animal, its head had the distinctive long skull shape of a whale’s. 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, ...

What are the groups of cetaceans?

The groups are cetaceans within Artiodactyla, as noted above; 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 dugongs—which live in rivers and shallow coastal waters and eat mainly seagrasses.

Where did the Pakicetus whales live?

Pakicetus, extinctgenusof early cetaceanmammalsknown from fossilsdiscovered in 48.5-million-year-old river deltadeposits in present-day Pakistan. Pakicetusis one of the earliest whalesand the first cetacean discovered with functional legs. In addition, it still retained many other features of terrestrial mammals, ...

What are the features of a cetacean?

The ancient Greeks recognized that cetaceans breathe air, give birth to live young, produce milk, and have hair —all features of mammals.

When was the Pakicetus first discovered?

It was first discovered in Pakistan and was named by Philip Gingerich and Donald Russell in 1981. Its name means “Pakistan whale.”

What does the name Pakicetus mean?

Its name means “Pakistan whale. ”. If you knew nothing about this mammal other than what you’ve seen in Pakicetus pictures, then you might never guess that it was one of the earliest whales found. That’s because it doesn’t look aquatic at all.

What is the skeleton of a pakicetus?

The Pakicetus skeleton reveals several details regarding the creature's unique senses and provides a newfound ancestral link between terrestrial and aquatic animals. As previously mentioned, the Pakicetus' upward-facing eye placement was a significant indication of its habitat. Even more so, however, was its auditory abilities. Like all other cetaceans, Pakicetus had a thickened skull bone known as the auditory bulla, which was specialized for underwater hearing. Cetaceans also all categorically exhibit a large mandibular foramen within the lower jaw, which holds a fat pack and extends towards the ear, both of which are also associated with underwater hearing. " Pakicetus is the only cetacean in which the mandibular foramen is small, as is the case in all terrestrial animals. It thus lacked the fat pad, and sounds reached its eardrum following the external auditory meatus as in terrestrial mammals. Thus the hearing mechanism of Pakicetus is the only known intermediate between that of land mammals and aquatic cetaceans." 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.

How big is a pakicetus?

Based on the skull sizes of specimens, and to a lesser extent on composite skeletons, species of Pakicetus are thought to have been 1 metre (3 ft 3 in) to 2 metres (6 ft 7 in) in length . Pakicetus looked very different from modern cetaceans, and its body shape more resembled those of land-dwelling hoofed mammals.

What is the difference between a pakicetus and a cetacean?

Pakicetus looked very different from modern cetaceans, and its body shape more resembled those of land-dwelling hoofed mammals. Unlike all later cetaceans, it had four fully functional long legs. Pakicetus had a long snout; a typical complement of teeth that included incisors, canines, premolars, and molars; a distinct and flexible neck;

What did the teeth on Pakicetus' skull mean?

The first fossil found consisted of an incomplete skull with a skull cap and a broken mandible with some teeth. Based on the detail of the teeth, the molars suggest that the animal could rend and tear flesh. Wear, in the form of scrapes on the molars, indicated that Pakicetus ground its teeth as it chewed its food. Because of the tooth wear, Pakicetus is thought to have eaten fish and small animals. The teeth also suggest that Pakicetus had herbivorous and omnivorous ancestors.

Where are the orbits of cetaceans located?

However, Thewissen et al. 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. Just like Indohyus, limb bones of pakicetids are osteosclerotic, also suggestive of aquatic habitat" (since heavy bones provide ballast). "This peculiarity could indicate that Pakicetus could stand in water, almost totally immersed, without losing visual contact with the air."

Which cetacean has a large mandibular foramen?

" Pakicetus is the only cetacean in which the mandibular foramen is small, as is the case in all terrestrial animals.

Is Pakicetus a cetacean?

Classification. 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). It was recognized as the earliest member of the family Pakicetidae.

What is the evolution of Pakicetus?

It was only over the course of the Eocene epoch that the descendants of Pakicetus began to evolve toward a semi-aquatic, and then fully aquatic, lifestyle, complete with flippers and thick, insulating layers of fat.

Where was the Pakicetus found?

One of the odd things about Pakicetus is that its "type fossil" was discovered in Pakistan, not normally a hotbed of paleontology. 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.

What are the descendants of Pakicetus?

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.

Is Pakicetus a terrestrial or aquatic mammal?

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 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." It was only over the course of the Eocene epoch that the descendants of Pakicetus began to evolve toward a semi-aquatic, and then fully aquatic, lifestyle, complete with flippers and thick, insulating layers of fat.

Where are pakicetids found?

Pakicetids have been found in or near river deposits in northern Pakistan and northwestern India, a region which was probably arid with only temporary streams when these animals lived there. No pakicetids have been found in marine deposits, and they were apparently terrestrial or freshwater animals.

What is the first pakicetid?

Dehm & Oettingen-Spielberg 1958 described the first pakicetid, Ichthyolestes, but at the time they did not recognize it as a cetacean, identifying it, instead, it as a fish-eating mesonychid. Robert West was the first to identify pakicetids as cetaceans in 1980 and, after discovering a braincase, Phillip Gingerich and Donald Russell described the genus Pakicetus in 1981. During the following two decades, more research resulted in additional pakicetid cranial material and by 2001 postcranial material for the family had been described. Though all parts of pakicetid postcrania are known, no complete skeleton from a single individual has been recovered. The pakicetid goldmine is the "H-GSP Locality 62" site in the Kala Chitta Hills where fossils from all three genera have been found. However, this site is so littered with bones that identifying bones from a single individual is impossible, and pakicetid skeletons are consequently composites of bones from several individuals.

What is the name of the whale that lived in Pakistan?

Pakicetidae ("Pakistani whales") is an extinct family of Archaeoceti (early whales) that lived during the Early Eocene in Pakistan.

What are the ear ossicles of a pakicetid?

Pakicetid ears had an external auditory meatus and ear ossicles (i.e. incus, malleus, tympanic ring, etcetera) similar to those in living land mammals and most likely used normal land mammal hearing in air.

Which vertebrae are longer, thoracic or pakicetid?

Pakicetid cervical vertebrae are longer than in late Eocene whales, the thoracic vertebrae increase in size from the neck backwards, and the lumbar and caudal vertebrae are longer than in modern cetaceans (but still shorter than in some extinct cetaceans with undulating spines.)

Is there a complete skeleton of a pakicetid?

Though all parts of pakicetid postcrania are known, no complete skeleton from a single individual has been recovered.

Do pakicetids have aquatic adaptations?

that "pakicetids were terrestrial mammals, no more amphibious than a tapir." According to them, none of the aquatic adaptations found in the oldest obligate aquatic cetaceans, basilosaurids and dorudontids, are present in pakicetids. Pakicetid cervical vertebrae are longer than in late Eocene whales, the thoracic vertebrae increase in size from the neck backwards, and the lumbar and caudal vertebrae are longer than in modern cetaceans (but still shorter than in some extinct cetaceans with undulating spines.) Motion in the spine of pakicetids was further reduced by the revolute zygapophyses (processes between the vertebrae) like in stiff-backed runners such as mesonychians. The sacral vertebrae are fused and the sacroiliac joints present like in land mammals and amphibious cetaceans.

Overview

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. It was a wolf-like animal, about 1 metre (3 ft 3 in) to 2 metres (6 ft 7 in) long, and lived in and around water where it ate fish and small animals. The vast majority of paleontologists regard it as the most basal whale, representing a transitional stage between land mammals and whales. It belongs to the even-toed ungulates wit…

Description

Palaeobiology

History of discovery

Classification

See also

Notes