Agriotherium

Name: Agriotherium ‭(‬Sour beast‭)‬.
Phonetic: Ag-ree-o-fee-ree-um.
Named By: Wagner‭ ‬-‭ ‬1837.
Synonyms: Agriotherium coffeyi,‭ ‬Hyaenarctos.
Classification: Chordata,‭ ‬Mammalia,‭ ‬Carnivora,‭ ‬Arctoidea,‭ ‬Ursidae,‭ ‬Ursinae.
Species: T.‭ ‬sivalensis‭ (‬type‭)‬,‭ ‬T.‭ ‬africanum,‭ ‬T.‭ ‬inexpetans,‭ ‬T.‭ ‬schneideri.
Diet: Probably an Omnivore.
Size: Approximately‭ ‬2.7‭ ‬meters long and up to around‭ ‬650‭ ‬kilograms.
Known locations: Across Africa,‭ ‬Eurasia and North America.
Time period: Serravalian of the Miocene through to the Piacenzian of the Pliocene.
Fossil representation: Multiple individuals.

       One of the better known bears in the worlds fossil record,‭ ‬the Agriotherium genus is also easily one of the largest currently known.‭ ‬With this large size it would be tempting to portray Agriotherium as a savage killers of any animal that might be unfortunate enough to be in its way,‭ ‬yet like with‭ ‬its more famous relative Arctodus‭ (‬better known as the giant short faced bear‭) ‬first impressions may in this case be deceptive.‭ ‬The post cranial skeleton of Agriotherium is that of a large but relatively underpowered animal that simply does not seem to have the skeletal framework necessary to cope with high stresses,‭ ‬such as those expected to be‭ ‬encountered while undergoing extreme physical exertion‭ (‬i.e.‭ ‬catching and subduing struggling prey‭)‬.‭ ‬The second clue is that Agriotherium has a proportionately short snout to that seen in many other bears.‭ ‬The advantages of having a short snout are simple,‭ ‬it means that whatever is being bitten,‭ ‬is closer to the point of jaw articulation‭ (‬fulcrum‭) ‬so that greater force can be brought to bear‭ (‬no pun intended‭) ‬against it.‭
       These are all features that are common to Arctodus which also has isotopic analysis of its bones revealing that it was eating nearly every type of animal in its ecosystem,‭ ‬something very unusual for a predator,‭ ‬but common for a scavenger.‭ ‬Given the superficial similarity in form between Agriotherium and Arctodus,‭ ‬it’s reasonable to speculate that Agriotherium may have been a specialised scavenger,‭ ‬a theory that is becoming increasingly put forward for Arctodus.‭ ‬Again,‭ ‬the concept is very simple,‭ ‬by being bigger than any other predator on the land,‭ ‬Agriotherium could in effect bully the smaller predators away from their kills.‭ ‬This draws parallels in bear/wolf interaction that is observed in the wild even today,‭ ‬where grizzly bears will watch a pack of wolves bring down a prey animal,‭ ‬just to charge on in and drive them off after they have done all of the work for it.‭ ‬This fits with the surprisingly gracile skeleton of a large animal like Agriotherium,‭ ‬since if it was letting other predators do the work and the killing for it,‭ ‬why waste precious nutrients and calories upon developing and maintaining a skeleton stronger than it needed to be‭?
       Another thing to consider is that if Agriotherium was a scavenger then it was likely getting to carcasses after all of the choice pieces of meat had been consumed with perhaps only bones being left.‭ ‬This would probably not be enough to thwart Agriotherium from a meal however since the short snout,‭ ‬strong jaw closing muscles and robust construction of the skull and jaws were all the things that Agriotherium needed to develop massive bite force.‭ ‬Computer modelling in a‭ ‬2012‭ ‬study‭ (‬see links below‭) ‬confirmed that Agriotherium had one of the largest bite forces known amongst the members of the Carnivora‭ (‬A group of mammals that includes dogs,‭ ‬bears,‭ ‬cats,‭ ‬pinnipeds etc which are specially adapted to exist by eating meat‭)‬.‭ ‬By being able to crack open bones,‭ ‬Agriotherium could access and eat the bone marrow within,‭ ‬and for those not familiar,‭ ‬bone marrow is one of the most nutritious parts of an animal,‭ ‬and can last for several years after an animals death when encased inside of the bones.
       The idea of Agriotherium being what is termed a‭ ‘‬hyper-carnivore‭’ ‬is plausible,‭ ‬though it is not certain that Agriotherium only ate meat.‭ ‬Like with bears today,‭ ‬Agriotherium may have also supplemented its diet with fruits and certain plants,‭ ‬particularly tougher ones that required strong jaws.‭ ‬However the scavenger theory does actually fit better with Agriotherium in terms of the age of known fossils.‭ ‬Agriotherium first appears just after halfway through the Miocene before disappearing at the end of the Pliocene.‭ ‬The similar Arctodus however begins to appear in the Pliocene before becoming most numerous during the Pleistocene.‭ ‬It might be that Agriotherium was one of the first specialised scavenger bears but was eventually replaced in the worlds ecosystems by more‭ ‬advanced versions that form separate genera,‭ ‬as well as possibly other bone crunching animals such as hyena.

Further reading
- Ecomorphology of the giant short-faced bears Agriotherium and Arctodus,‭ ‬B.‭ ‬Sorkin‭ ‬-‭ ‬2006.
- Finite element analysis of ursid cranial mechanics and the prediction of feeding behaviour in the extinct giant Agriotherium africanum,‭ ‬C.‭ ‬C.‭ ‬Oldfield,‭ ‬C.‭ ‬R.‭ ‬McHenry,‭ ‬P.‭ ‬D.‭ ‬Clausen,‭ ‬U.‭ ‬Chamoli,‭ ‬W.‭ ‬C.‭ ‬H.‭ ‬Parr,‭ ‬D.‭ ‬D.‭ ‬Stynder,‭ ‬S.‭ ‬Wroe‭ ‬-‭ ‬2012.

----------------------------------------------------------------------------

Random favourites