I’m afraid this will make very little sense without reading The Patriarchal Bear.
Let’s pretend in some alternate universe, C. H. Merriam did not Fail Taxonomy Forever and North America has scores of species of bears roaming around. It’s probably the universe next door to the Cryptozoologicon. One of the bears is something special; a small tremarctine from the Canadian Arctic, just one of two survivors from a once-mighty lineage. Unlike the bear of our universe — which was just an immature female Grizzly with low cusps on some of its teeth — this ‘Vetularctos inopinatus‘ actually has tremarctine traits such as a short and deep skull, large molars, lateral orbits, et cetera. And just because, let’s say this specimen was actually a large male that wandered a few hundred kilometers south from its normal distribution in the Canadian Arctic Archipelago.
But which tremarctine is it? Arctodus simus was present in eastern Beringia and may have had a competitive exclusive relationship with Brown Bears (Barnes et al. 2004). So perhaps Merriam’s Bear could be a dwarfed population of A. simus forced into a marginal habitat after the re-invasion of Brown Bears. But, eh, Surviving Arctodus is pretty played out. In our universe, the extant Spectacled Bear descended from the North American Tremarctos floridanus in the late Pleistocene or early Holocene (García-Rangel 2012, citing various); the biogeography of that split is still sufficiently mysterious for me to speculate, hey, why not have a sister species of the Spectacled Bear move north after the Last Glacial Maximum? Reclassifying ‘Vetularctos inopinatus‘ as Tremarctos inopinatus also opens up lots of interesting ecological possibilities.
Spectacled Bears are omnivores, mainly feeding on fruits and leaves, but they also have adaptations for preying on small prey (García-Rangel 2012, citing various). Feeding heavily on palms, bromeliads and fruits is probably going to be out of the question for Merriam’s Bear, unfortunately. Merriam’s Bear is also not much larger than Spectacled Bears — Merriam described the skull with a basal length of 26.8 cm, Spectacled Bears have a maximum total skull length of 26.3 cm (García-Rangel 2012, citing various) — so perhaps a large individual would be around the 200 kg mark. While still pretty big, this could make macropredation a rare affair and opens up the possibility of predation from Polar Bears, but less mass to support could make survival in a harsh landscape more plausible.
Could a bear even survive in the Canadian Arctic Archipelago? Barren Ground Grizzlies are typically thought to be absent from that area, but they have been recorded as far north as Melville Island; such vagrant bears have apparently fed on pinnipeds and (female and juvenile) polar bears, and could presumably eat sedges, caribou, and muskoxen as well (Doupé et al. 2007). Perhaps Merriam’s bear could feed heavily on hares and lemmings and have adaptations for taking a wide variety of the plants which still grow that far north. It still sounds like a pretty rough existence and I imagine Merriam’s Bear was one of the very last of its kind.
So, to be clear, this is all just speculative biology. I’m surprised that creating a plausible-ish scenario worked out as well as it did. It was certainly easier than for Bergman’s Bear, which doesn’t even exist in this bear-heavy alternate universe. Speaking of which, I should probably take a break from cryptid bears for a while.
Barnes, I. et al. (2004) Dynamics of Pleistocene Population Extinctions in Beringian Brown Bears. Science 295 2267–2270. Available.
Doupé, J. et al. (2007) Most Northerly Observation of a Grizzly Bear (Ursus arctos) in Canada: Photographic and DNA Evidence from Melville Island, Northwest Territories. Arctic 60(3) 271–276.
García-Rangel, S. (2012) Andean bear Tremarctos ornatus natural history and conservation. Mammal Review 42(2) 85–119.