Amphicyon ingens vs Kodiak bear

[Deleted]

What about an amphicyon?

[OldGreenGrolar]

Amphicyon ingens



Amphicyon was the typical bear-dog amphicyonid with morphology similar to both bears and dogs. With its robust build and maximum length of 2.5 m (8 ft), the largest species looked more like a bear than a dog. It had a large heavy tail, thick neck, robust limbs and teeth like a wolf. It was probably an omnivore with a lifestyle comparable to that of the brown bear. A single specimen was examined by Legendre and Roth and estimated to have a body mass of 84.2 kg (190 lb), roughly half that of Ischyrocyon and twice that of Epicyon which shared its time period and habitat. A. ingens was much bigger: Sorkin (2008) estimated the largest known specimen (AM 68108) to weigh 600 kg, making it the largest amphicyonid and one of the largest known carnivorous land mammals.





Kodiak Bear - Ursus arctos middendorffi
.


The Kodiak bear (Ursus arctos middendorffi), also known as the Kodiak brown bear, sometimes the Alaskan brown bear, inhabits the islands of the Kodiak Archipelago in southwest Alaska. The largest subspecies are the Kodiak bear (U. a. middendorffi) and the questionably distinct peninsular or coastal brown bear (U. a. gyas). Once mature, the typical female Kodiak bear can range in body mass from 120 to 318 kg (265 to 701 lb) and while from sexual maturity onward male ranges from 168 to 675 kg (370 to 1,488 lb).




Credited to Carnivora.

What would be the outcome between two powerful animals?

[King Kodiak]

Firstly, this was the killing technique of Ingens:

Giant bear-dogs of the genera Amphicyon and Ischyrocyon (Carnivora, Amphicyonidae, Amphicyoninae) were the largest carnivorans in North America during middle and late Miocene (17.5–8.8 Mya) with a dental and skeletal morphology that combined features found in living Ursidae, Canidae, and Felidae. This study tests previously proposed models of diet and hunting behaviour of these extinct carnivorans. Relative grinding area (RGA) of lower molars and wear pattern on upper molars suggest that bear-dogs were carnivorous. Amphicyon and Ischyrocyon possessed skeletal features of both ambush (short distal limb segments) and pursuit (caudally bent olecranon process of ulna) living predators. Therefore, bear-dogs probably pursued their prey (mediportal ungulates) for a longer distance but at a slower speed than do living ambush predators. Upon catching up to its prey a bear-dog probably seized it with powerfully muscled forelimbs and killed it by tearing into its ribcage or neck with canines set in a narrow rostrum.

www.researchgate.net/publication/40661208_Ecomorphology_of_the_giant_bear-dogs_Amphicyon_and_Ischyrocyon

So in my opinion, at same weight, if should be 50%. And then, whoever has a weight advantage should win more times.

[OldGreenGrolar]

There are some posters that claim that the amphicyon ingens has strong bone crushing jaws (Verdugo might have some info on this one) and similar grappling abilities as a bear (the source you posted seems to confirm this). The Kodiak bear's jaws can still do damage to the amphicyon. Therefore, it is going to be a fierce grappling match. I think out of all extant bears, only the Kodiak bear and polar bear can fight with the amphicyon ingens. Both the amphicyon ingens and the Kodiak bear will beat a polar bear at parity.

[brobear]

Result of your conversion:
600 kilograms is equal to
1,322.77 pounds (avoirdupois)

At weight parity, this fight might go either way. Amphicyon has the bite-force advantage. My guess, the real bear has the strength and grappling skills advantage. Brute strength probably goes to the true-bear as well.

[OldGreenGrolar]

@verdugo. Would you like to give us your opinion when you have time? Thanks in advance.

[OldGreenGrolar]

Comparison:


Thus, the combined contraction of the muscles subscapularis and subscapularis minor would improve the shoulder joint stability during the grasping and pulling actions in ursids and amphicyonids (Hunt 2009), as it has been also proposed for P. flavus and S. batalleri (Salesa et al. 2008). In ursids, the development of both the postscapular fossa and the teresmajor process besides the mobile shoulder articulation and the overall powerful shoulder musculature have been related to the ability of this group for climbing trees, an activity that implies that part of the body weight is supported by the forelimbs (Davis 1949; Argot 2003, 2010), but also to other types of behavior, such as overturning stones and digging (Gambaryan 1974).


Siliceo (2014)

Credited to Rorqual


carnivora.net/african-lion-v-grizzly-bear-t23-s240.html

[Deleted]

Oct 30, 2019 7:58:38 GMT -5 OldGreenGrolar said:

Would you like to give us your opinion when you have time? Thanks in advance.

Sorry for my late reply, i just got caught up on doing other things but anyway, i guess it's better late than never. I don't really have much interest in non-sympatric match-up so i have no opinions on who i think should win. However, i can still give you a run down of their morphology so that you can decide on your own who you think is the appropriate winner

You're correct that from Kodiak's source (Sorkin 2006) and Rorqual's source, it's unlikely that Amphycyon would have been inferior to modern Bears when it comes to grappling.
See Argot 2010

The morphology of the whole forelimb of Amphicyon
major is very much like that of a bear.
As in extant bears, an accessory fossa and a wide
neck characterise the scapula of the fossil taxon.
These two features as well as the broad spinati
fossa suggest a heavy scapular musculature. In
addition, abductors (deltopectoral muscles) and
flexors (biceps + brachialis) were also powerfully
developed. The ball-shaped humeral head, higher
than both tubercles, indicates a mobile shoulder
joint. The elbow joint is very similar to that of a
bear, indicating an abducted humerus with usual
flexed positions and a maximised humeroulnar
stability in extensions.

Even assuming that Bears are better grappler, the discrepancies should not be large based on what we know of their morphologies

In term of Bite force, i don't know if any researchers have ever attempted to estimate Bear-dog's BF, i cannot find any studies regarding this. However, just by looking at the skull, we can tell that it should have quite a strong BF judging by its developed sagittal crest.


The other thing i need to point out is the skull size. See Sorkin 2006

The largest Amphicyon has a Basilar Skull length up to 52 cm which is downright enormous. Please note Basilar length is a smaller measurement of Skull length that Greatest skull length (see what these Skull length measurements really mean here)

So a 52 cm Basilar length means that the Greatest skull length would probably be close to 60 cm in length (i haven't done precise measurement so don't quote me on that but i think the Greatest skull length should be in that range). This much larger (at least in Length) than any Bears' skulls that i know of. Larger (in Length) than those of the largest Arctodus and Cave bear's skulls that i know of. See Sorkin 2006, Table 1, the largest Arctodus's skull has a condylobasal length of 'only' 463 mm, compared to 520 mm of the Bear-dog. Arctodus's skull may still taller and wider but idk, i have no measurements of Amphicyon's skull width or height.

Needless to say, Amphicyon's skull is much larger (at least in length) than an average Kodiak bear's skull, who is usually <450 mm in Greatest skull length.

See Figueirido 2011 regarding Amphicyon's skull:

However,
it is worth noting that the skulls of some amphicyonids are dis−
proportionately large relative to their postcranial bones (Hunt
1998), which could introduce a source of bias in their esti−
mated body masses.

The rea−
son is that some beardogs have relatively large heads and
strong jaws compared to any living terrestrial caniform. In
fact, there is probably a different allometric pattern of head
length on body mass in amphicyonids and in the creodont
Hyaenodon horridus Leidy, 1853, relative to other carni−
vores (Van Valkenburgh 1990; Hunt 1998).

This is especially the case for Amphicyon ingens,
which exhibits the largest conical canines among the amphi−
cyonines, a robust skeleton and an extremely developed
sagittal crest that indicates the presence of massive jaw mus−
cles (BF, personal observation). These features together with
specializations of the limbs and feet suggest a large ambush
predator.

Also, body
mass estimates derived for amphicyonids from skull mea−
surements should be taken with caution, not only because
these functions have lower predictive power than those ad−
justed with the postcranial skeleton, but also because amphi−
cyonids have disproportionately large heads in relation to
body mass (Finarelli 2006).

I hope this is clear

[King Kodiak]

Thanks for that info Verdugo. So both animals are very alike in the grappling department. The Amphicyon definitely had more bite force. It also had a mobile shoulder joint. So, in my opinion, at same weight, it would still be 50%.

[OldGreenGrolar]

The account is credited to Tonatiuh from Carnivora.

[OldGreenGrolar]

Amphicyon ingens is the only mammalian land carnivore to rival a bear in terms of grappling skills.

[Deleted]

What is an amphicyon?

[King Kodiak]

Jan 23, 2020 17:31:40 GMT -5 @lazarlazar said:

What is an amphicyon?

Read the first posts of this thread, all the info is there.