But I have to agree that the animal’s armament and locomotor mechanism – like that of T. rex, among others – seem to point to something that could take big game on its own. And would, whenever hunger meshed with opportunity.

One would think that science would learn a lesson from the spotted hyena, which was thought nothing but a scavenger of kills until the late sixties. How about this for speculation: Arctodus being a social animal, running prey in relays, using group ambush tactics, taking down the biggest animals the way lions, hyenas and wolves do? (A bigger question: why don’t biologists have more fun speculating?)

I’d imagine that the closest we have to a terrestrial critter that eats only carrion – although I’d imagine even they could make exceptions – is vultures, and they can travel great distances, with an aerial perspective and little relative effort, apparently cooperating with conspecifics and taking advantage of cues provided by other species, e.g., black vultures with their eyesight watching for turkey vultures with their incredible sense of smell.

I’m not seeing an animal restricted to ground travel finding enough carrion to finance – think about it – the enormous amount of travel it would have to do to find it. As we so often ask here on this site, trying to explain the paucity of cryptid remains: how many dead critters does anyone find out there? (Please don’t tell me other critters just find them first.) I don’t care how tall Arctodus stood, or how good its nose was, or how specialized its undercarriage to long, wolf-like sojourns. Wolves hunt to eat.

That says enough to me.

Although if it didn’t, this question would: don’t the hunters always take the best food first? Do we really expect an animal that must travel extensively to eat to make its whole living off of low-grade leftovers? Or to always be there in time to grab whole kills, which raises the question of how Arctodus’s competition made it at all?

Although I do have to say this. Hearing a scary critter like Arctodus referred to as a “kleptoparasite” was good for a chuckle. Imagine something like THAT hanging off of you.

As an aside, experts of the Zoological Society of London in 2007 announced they had done some modeling on predators, considering nutrition, energy intake/expenditure, etc., and come to the conclusion that one ton is about the limit of size for a terrestrial mammalian carnivore. A polar bear killed in Alaska in 1960 reportedly weighed 1,002 kg: that individual might have been one of the largest carnivorous mammals that ever lived.

BTW, I have no idea why the MonsterQuest announcement says the crew went to New Jersey in pursuit of this story. Do we have bears hiding out in the Witness Protection Program or something?

I was told the mystery of MacFarlane’s bear will be solved tonight. So everyone tune in!

When I hear stuff like “Schubert, as a research scientist, will certainly be on the side demanding hard evidence,” I start to worry. Just like when I hear a scientist say something like “If I’m part of this episode, most likely I’m going to be your spoiler,” I start to worry.

Skeptical scientists have a bad habit of forgetting what constitutes evidence.

I really hope he isn’t going to start spouting questions like “where’s your body?” or “why hasn’t anyone found any recent bones?” “Hard” evidence is what we call “proof.” Sightings are not hard evidence. But if there are a lot of them, and the observers seem like people who should know what they’re talking about, and the sightings seem to describe creatures and behavior that are generally plausible, significantly frequent, and internally consistent, there may be something worth following up.

Now, when one talks about the continued existence of an extinct bear, there’s complicating factors. A grizzly could look like a short-face; that’s pretty plausible. Most people seeing a bear won’t be qualified to judge species differences. A bear isn’t an eight-foot bipedal ape. “Well, its face looked kind of short and its legs kind of long” …well, that’s problematical.

I would just want Schubert to ask for, and review, the evidence.

Not the proof, because, well, we don’t have that. Yet.

The estimation of 1 ton was made for the largest known specimen of Arctodus simus. Furthermore this estimation is most probably much too high. This animals had very different proportions to modern bears, and weight estimations based on limb-bones alone are not the best way. Arctodus looked mainly so huge because it had such long legs, but its body was not bigger than those of a very large modern Kodiak or Kamtchatka bear. The biggest modern polar bears even surpass clearly in mass the largest known Arctodus simus specimen, and even those are still under 1000kg.

Daniel Reed made probably one of the best Arctodus reconstruction, which is directly based on a skeleton, so the proportions are exactly right.

It shows a size comparison of the largest known specimen, but if you look at the body alone, it is not that big. I know another size comparison Daniel Reed made together with a scaled up polar bear (whose shoulder height was even a bit under the record-sizes) of about 1500 Ibs, and the polar is clearly heavier.

The weight of the largest Arctodus simus specimen we know was much more probable in the 600 Ibs range, but even among male members of the Arctodus simus subspecies the average was lesser. So even the largest ones of the largest subspecies were “only” about 600kg (what is still huge), the average was still much smaller, and the other subspecies were even smaller too. And the females were even still smaller.

Carl Buel made also some great reconstruction drawings of Arctodus in comparison with a man (a cool picture of himself) which show clearly that Arctodus was far away from being as massive as a big bull (with a weight of about 1 ton).