During the 1890s, Russian palaeontologist Vladmir Prokhorovich Amalitsky discovered fossil skeletons remains of new genus, found on creek in a bank escarpment which is dated from Permian period in Northern Dvina, Arkhangelsk Oblast in Northern European Russia which was most important discoveries in late 19th and early 20th century as Permian fossils were only found in South Africa an India. Amalitsky conducted systemic research with his partner Anne P Amalitsky in Russia which he sent several findings of fossils of unknown animal to Warsaw, Poland in order to study the fossils. The process of collecting fossils on the creek lasted until 1914 due to the start of World War 1, they were taken to the Museum of Geology and Mineralogy of the Russian Academy of Sciences. Amalitsky had to take administrative activities and deal with difficult conditions which hindered his progress of fossil research in his last years before he unexpectedly died in 1917, he was able to collect two complete specimen skeletons of large gorgonopsids called Inostrancevia alexandri which he already proposed its species and genus name before he made a description of animal and, a published posthumously was made in 1922 after his death. The two skeletons were sent to the Instituite of Paleontology of the Russian Academy of Sciences. Despite not mentioning of the animal name origins, The name of Inostrancevia, was to honour of the renowned geologist Alexander Inostrantsev who was Amalitsky teacher.

 In 1927, One of Amalitsky colleagues, Pavel A Pravoslavlev, published the first formal description of the genus in which he mentions about the two known skeletons of Inostrancevia alexandri and several other species of animals that Amalitsky found during his find. However, Inostrancevia.Latifrons was the only recognised distinct species within the genus as it was only based on skulls discovered by Arkhangelsk Oblast which also contained incomplete skeleton from the village of Zavrazhye, located in Vladmir Oblast. In 1974, Leonid Tatarinov described the third species of Inostrancevia called I.uralensis which were based on rare remains of part of the skull from an smaller specimen than the other two species of Inostrancevia, located in Ural River, Orenburg Oblast. In 2023, the fourth species of Inostrancevia is called I.Africana which were based on two specimens found between 2010 and 2011 by Nthaopa Ntheri and John Nyaphuil at Nooitgedacht farm in the Karoo Basin, South Africa. The Two specimen found in Balfour formation were called "holotype NMQR 4000 and paratype NMQR 3707". In the same year, Christian F. Kammerer and his colleagues publish a revision on which confirms the two specimens of genus Inostrancevia were related to each other but, the Russian and African specimen were different enough to class themselves as their own valid species. 

In 1739, a French military expedition that was lead by Charles III Le Monye where they excavated in Big Bone Lick (located in state of Kentucky), they ere able to excavate fossil bones and teeth. In 1762, These fossils were taken to French naturalist Louis Jean-Marie Daubenton to be examined and analysed on on what these fossils belonged to, he noticed that there were similar to modern elephants and mammoths. In his conclusion, he proposed that the femur and tusk belonged to an elephants while the molars/cheek bones belonged to hippopotamus. In 1767, Peter Collinson credited Irish trader George Croghan for sending fossils evidence for him and Benjaim Franklin that proves the existence of North American proboscideans relatives. Collinson concluded that the peculiar grinders/molars were built for herbivorous diets which shows these mysterious North American proboscideans relatives were strict herbivores.   

In 1768, Scottish anatomist William Hunter and his brother John Hunter analysed the fossil tooth and tusk of mysterious North American proboscideans relatives after they took the fossil collection from Franklin and Lord Shelburne. Both the Hunter brothers noticed that they were not like those of modern elephants. Weirdly, Hunter proposed that these remains belonged to carnivorous elephant relatives that were completely separate from modern elephants and mammoths. Although, Hunter discovery was bit extreme and absurd about mastodon behaviours and diet, he was right that mastodon was complete separate lineage of proboscideans from modern elephants and mammoths.

In 1785, Reverend Robert Annan wrote an account based on the fossils that contained four molar (another that was broken and thrown away and vertebrae that the workers excavated and thrown away after they broke it . These findings were at Annan farm near Hudson River in New York in 1780.  Much like Hunter, Annan thought that these molars belonged to carnivorous animal while also speculating that these monstrous beasts went extinct at some point in the past.  After these findings and the scientific community accepting that these ancient proboscideans relatives were carnivorous,  this led to American statesmen Thomas Jefferson to speak his thoughts about these discoveries on Notes on the State of Virginia in 1785.  

In 1799,  labourers excavated a thighbone from the marl pit at John  Masten's farm in Newburgh, new York.  The labourers continue to excavated and found more fossil material that helped to complete the first skeleton of mysterious carnivorous proboscideans .  In 1801,  American painter and exhibitionist Charles Wilson Peale visited the farm to sketch illustration of the mysterious carnivorous proboscideans complete skeleton  and, he purchased and owned the fossil collection from Malten's farm for his own personal collection.  After the first skeleton discovered was excavated, the second skeleton was drilled in deep marl pit and assembled by Peale so he can present the specimen in his museum in Philadelphia in 1804.  He opened his exhibit to the members of the American Philosophical Society on December 24th while Peale opened his exhibit publicly in December 25th.  Peale exhibit has attracted thousands of visitors to see his monstrous proboscideans which helped to boost his museum into popularity and profitable while also making mastodon the symbol of US national symbol.  

Mastodon is part of extinct proboscideans family group called mammutidae that can be found in North America, South America, Eurasia and Africa.  They existed around Late Miocene until the Late Pleistocene and beginning of Holocene about 11,000 years ago. 

They usually characterised by having similar anatomical features of modern elephants but, they were shorter and bulkier than modern elephants, smaller ears, thick coat, straight forward tusks than curved, molars that were pointed cones than flat surface and low domed heads as opposed of high dome heads that are found in mammoths and modern elephants. Mammutidae were specialised wood eaters or xylophagy as opposed to grazer specialists, their diet consists of twigs, leaves, shrubs and trees in swampy and wet areas of woodland and coniferous forests. They also use their tusks to strip off the bark of trees to digest their food. Mammutidae possess broad feet and stubby, wide-splayed wide toes so they an walk on soft, waterlogged ground in wetter environments. Palaeontologists argued on whether they had thick coats like mammoths or hairless similar to modern elephants but, new discoveries helped to prove that they had shaggy coats to help them survive in colder climate. 

Mastodon share behaviours of modern elephants and mammoths as they were highly intelligent and social herding animals. The herd is lead by matriarch/older female mastodon and, consisted of females and calf while the bull lives in solitary lifestyle. Although, bulls may lived in unstable herds to support younger bulls. Much like modern elephant bulls, they will go through high levels of testosterone called musth where the bull is looking for a mate but, they become too aggressive and destructive to animals and rival bulls.  Mastodon fur would have shaggy and thick coat to help them to stay warm in cold climate, the fur would have been reddish brown. 

There was no official formation in Santa Fe River, Florida near the border of Gilchrist and Columbia Counties where Titanis fossils were discovered. There were also equids (Nannippus), proboscideans (mastodon) and prehistoric bone crushing dog called Borophagus that also found alongside with Titanis remains.