Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Mar 18, 2019 8:18:38 GMT -5
/\ The picture above looks a bit like a polar bear.
|
|
|
Post by King Kodiak on Nov 15, 2019 6:00:58 GMT -5
The Agriotherium genus had huge bears, Africanus was huge and it is known to have the strongest bite force of any bear in history. But why does it say it was larger than Arctotherium? It was not.
We already had a thread for Agriotherium brobear:
domainofthebears.proboards.com/thread/85/agriotherium But why does it say it was larger than Arctotherium? The Bear Almanacs get their information of old sources. Before the discovery of Arctotherium angustidens, Agriotherium Africanum was bigger than all known Arctotheriums. Right, i figured it was old sources.
|
|
|
Post by brobear on Jan 6, 2020 1:40:58 GMT -5
Agriotherium africanum
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 28, 2020 18:22:16 GMT -5
|
|
|
Post by King Kodiak on Feb 28, 2020 18:44:04 GMT -5
Post # 39....i dont know about a rhino. I really dont see any bear, even the largest, attacking a rhino. That one had to be imagination.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 28, 2020 18:46:09 GMT -5
If lions and tigers can do it so why not bears Short faced bears could hunt mammoth
|
|
|
Post by King Kodiak on Feb 28, 2020 18:50:18 GMT -5
If lions and tigers can do it so why not bears Short faced bears could hunt mammoth Because lions and tigers are 100% hunters/carnivores. Lions also do it in prides. Agriotherium Africanum, like all species of bears, was an omnivore, he could eat anything. He would have not taken that risk unless maybe desperate.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 28, 2020 18:56:35 GMT -5
I am pretty sure a large aggressive predatory male grizzly could kill an 800 kg adult female black rhino Bears are more powerful than big cats Maybe not kill but a bear can definately injure a rhino See a single lion did it From Lion predation on the African Black Rhinoceros and its potential effect on management. "In February 2002 at Lake Nakuru National Park, Kenya, a rhino calf was killed by a lion despite the mother putting up a considerable fight. This was exemplified by savage wounds on the shoulder and breast of the rhino and scratch marks on the flanks. The mother, Suzie, was considerably distressed by the incident. Despite the wounds being treated, it died a few months later." www.thefreelibrary.com/Lion+predation+on+the+African+Black+Rhinoceros+and+its+potential...-a0268790518
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 28, 2020 18:58:57 GMT -5
Thats rhinos
But can an a big aggressive predatory male grizzly kill an average giraffe with AMBUSH
|
|
|
Post by King Kodiak on Feb 28, 2020 19:01:29 GMT -5
Oh well yeah, an 800 kg female rhino, yeah. But that is a very small rhino of course. The bear would have to be same weight or larger. I was talking about the adult male rhinos.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 28, 2020 19:04:41 GMT -5
Agriotherium skull
|
|
|
Post by brobear on Feb 29, 2020 2:24:35 GMT -5
Not much is known of this bear's habits. Was it a typical omnivorous bear like a grizzly or was it primarily a carnivore? If primarily carnivorous, was Agriotherium a hunter or a scavenger?
|
|
|
Post by King Kodiak on Feb 29, 2020 9:09:50 GMT -5
Nothing is conclusive. But some researchers think that the broad, deep skull of Africanum was well suited to fight prey. Not to mention that Africanum had the strongest bite force of any bear in history. But nothing is conclusive just yet.
domainofthebears.proboards.com/post/1392/thread
|
|
|
Post by brobear on Feb 29, 2020 13:32:59 GMT -5
To fight prey or predators? Strong jaws are useful for crushing bones. Probably a bit of both hunter and scavenger.
|
|
|
Post by tom on Mar 4, 2020 19:01:34 GMT -5
|
|
|
Post by brobear on Jul 14, 2020 13:48:19 GMT -5
www.researchgate.net/publication/305661593_Diverse_diets_of_the_Mio-Pliocene_carnivorans_of_Langebaanweg_South_Africa Diverse diets of the Mio-Pliocene carnivorans of Langebaanweg, South Africa The Mio-Pliocene guild of carnivorans of Langebaanweg (LBW), South Africa, is phylogenetically and ecologically diverse. Unlike modern African fauna, this fossil sample contains a large ursid; although there are mustelids, herpestids and viverrids in Africa today, some of the LBW members of those families were much larger than their modern confamilials. There were also numerous felid species, including some that possess a more sabretoothed dental morphology, as well as several species of hyaenids that were very different from their modern confamilials. Questions remain about the dietary morphospace occupied by these fossils. Which taxa were predominately durophagous and which were the most hypercarnivorous? Did the level of durophagy and hypercarnivory in the LBW taxa reach the level of specialisation found in modern carnivores? In the current study, we evaluate the dietary specialisations of all the large terrestrial LBW carnivorans through analysis of the radii-of-curvature and intercuspid notches present in the mandibular dentition. We found that the LBW carnivorans had less sharp premolars than do their modern confamilials – an indication of greater durophagy. However, some families contain individuals with more extreme intercuspid notch patterns, indicating greater hypercarnivory. The ursid also possessed a suite of morphology unlike any modern carnivoran, exhibiting some morphology conducive to durophagy and some that places it functionally among the most hypercarnivorous of modern carnivorans. Thus it was likely capable of consuming high levels of both flesh and bone. ntroductionMembers of the order Carnivora exhibit a wide range of dietary adaptation and specialisation. Some members are ‘hypercarnivorous’, specialising in the consumption of ver tebrate flesh1-4 (e.g. felids), while others are ‘durophagous’, specialising in the consumption of bone or other obdurate foods1-4 (e.g. most hyaenids), insectivorous (e.g. the aardwolf, Proteles), frugivorous (e.g. the binturong and kinkajou, Arctictis and Potos), and even strictly folivorous (e.g. the bamboo-eating red and giant pandas, Ailurus and Ailuropoda). Most taxa in the order represent a mixture of several of these specialisations. As carnivorans have diversified, their craniodental morphologies have adapted to diverse dietary niches. Important dietary information can be gained from analysing carnivoran teeth, especially in relation to tearing, shearing, cracking or grinding habits during food processing. These morphological changes and their significance can be evaluated by analysing the craniodental adaptations, and correlating these adaptions with dietary categories (e.g. durophagous or hypercarnivorous). Analyses of premolar radii-of-curvature (ROC) and intercuspid notches (ICNs) show that tooth geometries correlate with today’s observed diets of modern carnivorans; more hypercarnivorous taxa have sharper (higher ROC scores) teeth that are comparatively more intricately notched (higher ICN scores) than durophagous taxa.1-3 The functional inferences are clear: sharper teeth are best for slicing ductile flesh, and yet this sharp edge is vulnerable to damage by particularly hard or tough foods. Likewise, numerous and sharp ICNs function to increase the linear sharp crests available for flesh slicing and also help focus slicing forces for ductile foods toward pinch points like the diamond-shaped slicing notches found in wire cutters. However, the well-developed, small and unsupported accessory cusps would be particularly vulnerable to breakage against hard foods like bone. Goal and objectiveThe overarching goal of this study was to expand on the assessment of LBW hyaenid diets3 to compare the morphology of the members of the terrestrial LBW carnivoran guild to modern carnivorans using analyses of dental ICN2 and ROC1 with the objective of evaluating the dietary niche space occupied by the large LBW carnivorans relative to that occupied by modern carnivoran lineages. Although both the geological context and taxonomic systematics of the LBW carnivorans are discussed more thoroughly in the previous literature (see below), we briefly discuss these in order to contextualise our fundamentally morphological study with particular emphasis on visually displaying some of the impressive specimens from this important location.
|
|
|
Post by brobear on Jul 14, 2020 13:49:49 GMT -5
CONTINUED: BackgroundLangebaanweg – a brief contextOriginally discovered during phosphate mining operations in the early half of the 20th century, the fossiliferous deposits at LBW are known for their diverse terrestrial and marine taxa that make LBW one of the most significant Mio-Pliocene fossil-bearing sites in Africa. The broader Langebaanweg deposits include four distinct formations in geological succession: Elandsfontyn (underlies the formation in question and rests on local bedrock); Saldanha (early- to mid-Miocene in age); Varswater (most intensively studied Tertiary sequence in southern Africa); and Bredasdorp (post-early Pliocene deposits). The Varswater formation is divided into three distinct Members that comprise the LBW ‘E’ Quarry – the focal sample of the present study – from where most of the highly studied and best understood Mio-Pliocene fossils in southern Africa have been unearthed. 2South African Journal of Science www.sajs.co.zaVolume 112 | Number 7/8 July/August 2016The Langeberg Quartzose Sand Member (LQSM) was deposited during the late Miocene and early Pliocene and is abundant in fossils from both vertebrates and inver tebrates and is thought to have resulted from repeated sedimentation events and the marine transgression of the Berg River.6 Hundreds of thousands of fossils have thus far been recovered from ‘E’ Quarry belonging to over 200 species, more than 80 of which are mammals. The remains of 13 out of 14 mammalian orders (excluding Sirenia) are represented, some of which no longer have relatives living south of the Sahara. The LBW ‘E’ Quarry is known for its fossils that have been found nowhere else in southwest Africa in such unprecedented quantity and quality. Fossils from this deposit reflect what has been interpreted as a deteriorating environment during the early Pliocene as well as its subsequent change to fynbos and open grasslands that can currently be seen in LBW.7 Within these two deposits, the following carnivoran families have been identified: Felidae (cats), Viverridae (civets), Hyaenidae (hyenas), Herpestidae (mongooses), Canidae (dogs), Ursidae (bears), Mustelidae (weasels) and Phocidae (seals). Carnivorans of Langebaanweg‘E’ Quarry is especially well known for its fossil carnivorans, which comprise one third of the mammals from the locality and make Carnivora the most diverse order within the assemblage. The fact that carnivorans are generally poorly represented at other late Miocene and early Pliocene sites in Africa makes the ‘E’ Quarry assemblage that much more valuable. Unique in such high numbers to this fossil site are the remains of at least 14 individuals of the giant extinct African bear Agriotherium africanum, which are not generally found together in such large numbers. This bear and many other large carnivores found at LBW (e.g. Ikelohyaena, Hyaenictitherium, Plesiogulo and Dinofelis) originally came from Eurasia when the drop in sea level at the end of the Miocene allowed passage into Africa via the Mediterranean land bridge. The subsequent rise of global sea levels at the beginning of the Pliocene drastically changed the climate in LBW from tropical to temperate – thus, the ‘E’ Quarry assemblage dates from a period when fauna were either adapting to changing environmental conditions or going extinct.
|
|
|
Post by brobear on Jul 14, 2020 13:55:05 GMT -5
CONTINUED: Ursidae Agriotherium was the most geographically dispersed member of the family Ursidae, with fossils found at sites in North America, Europe, Asia and Africa. It was the only ursid known to have inhabited sub-Saharan Africa. Agriotherium africanum, the species found in LBW, was very large (~540 kg29) and exhibited several relatively unique craniodental characteristics: a short-snouted, robust skull; a ‘chin’-like protrusion at the symphyseal region of the mandible; well-developed sectorial carnassials; and a premasseteric fossa. The only extant ursid to also have premasseteric fossae is Tremarctos, which also has sectorial carnassials reminiscent of Agriotherium. This has led to the hypothesis that Agriotherium may have given rise to the Tremarctos lineage and possibly the other extant ursids. Agriotherium may have been outcompeted and replaced by modern bears. Ursidae is a fairly young family, and likely evolved from caniform ancestors only 23–24 million years ago, and Agriotherium exhibited many craniodental characteristics that are reminiscent of these ancestors (such as a robust P4) which has caused controversy over whether or not Agriotherium should be considered an ursid or an amphicyonid. Previous research on Agriotherium has focused largely on estimating its bite force in relation to body mass for the purposes of reconstructing evolutionary anatomical adaptations and hypothetical feeding ecology. For instance, one study concluded that Agriotherium had an absolute bite force higher than that of any other mammalian carnivore and that, even relative to body mass, Agriotherium’s bite force was still formidable. However, the wide range of feeding niches and masticatory adaptations occupied by modern ursids make it difficult to predict Agriotherium’s diet. For example, the giant panda is able to generate and sustain a powerful bite force comparable to Agriotherium in order to exploit bamboo, its primary food source, although some studies have claimed that Agriotherium actively hunted and consumed large vertebrates. Other studies have suggested that the diets of these ursids included a lot of vegetation, while still others have argued that Agriotherium is adapted largely for durophagy. Because of the presence of a true carnassial complex and robust molars fit for durophagy (Figure 1b), the growing consensus seems to be that Agriotherium was a predator-scavenger.
|
|
|
Post by brobear on Jul 14, 2020 14:00:35 GMT -5
|
|
|
Post by King Kodiak on Jul 14, 2020 14:17:56 GMT -5
Quote from reply #41:
|
|