Fossil Ursids of the National Parks Service

Here we are, a little later than usual for the annual "Fossil [Group] of the National Park Service" but present nonetheless. I decided to get in another group of carnivorans, this time the bears (Ursidae). If you've been here for the cats and dogs, you can probably guess the basic shape of things: a few records earlier in the Cenozoic, then a big slug in the Pleistocene into the Holocene, with many of the records representing living species. That is indeed how it goes with the bears as well, with a couple of quirks: the bear record goes back as far as the dog record, into the Chadronian (Late Eocene), but is never as diverse as the records for either cats or dogs. Essentially you get a couple of genera or species in a formation, and that's about it. Bears, it seems, have never felt the need to be profuse about the business of being bears. It's not quite "one-bear-fits-all", but bears favor generalism, and there's only room for so many species of generalists in one place and time.

I have records of bear fossils in 30 NPS units, although admittedly you may not be impressed by the paleontological qualifications of some of them (there are two extant species in North America and Ursus americanus, the good old black bear, has been found all over the place from the Pleistocene into the Holocene, so a given undated black bear record may be more recent than some people are comfortable with counting as paleontological).

A map of the bear necessities: 1. Ebey's Landing National Historical Reserve; 2. North Cascades National Park Service Complex; 3. Lake Roosevelt National Recreation Area; 4. Nez Perce National Historical Park; 5. John Day Fossil Beds National Monument; 6. Oregon Caves NM and Preserve; 7. Lava Beds NM; 8. Hagerman Fossil Beds NM; 9. Craters of the Moon NM and Preserve; 10. Yellowstone National Park; 11. Timpanogos Cave NM; 12. Sequoia and Kings Canyon National Parks; 13. Channel Islands NP; 14. Bering Land Bridge NPres; 15. Yukon-Charley Rivers NPres; 16. Chaco Culture NHP; 17. Guadalupe Mountains NP; 18. Amistad NRA; 19. Wind Cave NP; 20. Badlands NP; 21. Agate Fossil Beds NM; 22. Niobrara National Scenic River; 23. Ozark National Scenic Riverways; 24. Buffalo National River; 25. Lewis & Clark National Historical Trail (Big Bone Lick); 26. Mammoth Cave NP; 27. Cumberland Gap NHP; 28. Chickamauga and Chattanooga National Military Park; 29. Potomac Heritage National Scenic Trail; 30. Valley Forge National Historical Park.

Indeed, 25 of the 30 records are exclusively Quaternary, where it's basically a tale of two genera: the short-faced bear Arctodus, represented by A. pristinus and A. simus at five units; and Ursus, rather more widely distributed. The black bear is more widely represented, identified at 13 park units as opposed to the grizzly (U. arctos) at perhaps six. (The grizzly is a relative latecomer and more or less appropriated the role of Arctodus, which was certainly large and doubtless memorably ill-tempered on occasion like any other bear, but was not the slavering death beast it is sometimes depicted as.) For much of the Quaternary, the bear fauna at a given location would have been the smaller black bear and a rarer larger bear, a species of short-faced bear or the brown bear. Many of these records are also from caves, which is probably not surprising.

If you're curious about the Arctodus records, they are from Channel Islands National Park (a single toe bone that seems to have gotten to San Miguel Island as takeout carried by a large scavenging bird; Mychajliw et al. 2020), Nez Perce National Historical Park (from the Spaulding Unit, found charred and in association with archeological material), Ozark National Scenic Riverways, Potomac Heritage National Scenic Trail (Cumberland Bone Cave), and Valley Forge National Historical Park (Port Kennedy Bone Cave). The champion is Port Kennedy Bone Cave, which was positively crawling with A. pristinus (at least 25 individuals, compared to a minimum of eight black bears). Cumberland Bone Cave is not quite as well-stocked with Arctodus, but does have an endocast from a young black bear (Eshelman et al. 2025).

There are only five parks with pre-Quaternary records, all of them usual suspects. Badlands National Park has Subparictis (technically an ursoid per Wang et al. 2023, but who's counting?) in the Late Eocene-age Chadron Formation and Early Oligocene-age Brule Formation (Benton et al. 2015). The most varied record is probably at John Day Fossil Beds National Monument, as the John Day Basin has various species in the Turtle Cove Member (late Early Oligocene) and Haystack Member (Late Oligocene) of the John Day Formation, the Mascall Formation (early Middle Miocene), and the Rattlesnake Formation (late Late Miocene) (Fremd 2010). The others fill in around the edges. There's Cephalogale in the Anderson Ranch Formation (Early Miocene) at Agate Fossil Beds NM; Hemicyon in the Valentine Formation (Middle Miocene) of Niobrara National Scenic River; and Agriotherium and Ursus abstrusus in the Glenns Ferry Formation (Pliocene) of Hagerman Fossil Beds NM.

Five species of fossil bears have been named from NPS units, and a sixth may have been, but only four of the names are still in use. These are:

• Indarctos? oregonensis Merriam et al. (1916), from the Rattlesnake Formation of what is now John Day Fossil Beds NM, now Indarctos oregonensis without the question mark
• Parictis dakotensis Clark (in Scott and Jepsen 1936), from the Chadron Formation potentially from within Badlands NP, now assigned to Subparictis
• Parictis (Campylocynodon) parvus Clark and Beerbower (1967), from the Chadron Formation of Badlands National Park, now assigned to Subparictis
• Ursus abstrusus Bjork (1970), from the Glenns Ferry Formation of Hagerman Fossil Beds NM
• Ursus haplodon Cope (1896), from Port Kennedy Bone Cave, Valley Forge NHP, now considered a synonym of Arctodus pristinus
• Ursus (Euarctos) vitabilis Gidley (1913), from Cumberland Bone Cave, Potomac Heritage NST, now considered a synonym of Ursus americanus

And now, an actual National Park bear (a black bear seen near a road in Yellowstone).

References

Benton, R. C., D. O. Terry, Jr., E. Evanoff, and H. G. McDonald. 2015. The White River Badlands: geology and paleontology. Indiana University Press, Bloomington and Indianapolis, Indiana.

Bjork, P. R. 1970. The Carnivora of the Hagerman Local Fauna (Late Pliocene) of southwestern Idaho. Transactions of the American Philosophical Society New Series 60(7): 3–54.

Clark, J., and J. R. Beerbower. 1967. Geology, paleoecology, and paleoclimatology of the Chadron Formation. Pages 21–74 in J. Clark, J. R. Beerbower, and K. K. Kietzke. Oligocene sedimentation, stratigraphy, paleoecology and paleoclimatology in the Big Badlands of South Dakota. Field Museum of Natural History, Chicago, Illinois. Fieldiana: Geology Memoirs 5.

Cope, E. D. 1896. New and little known Mammalia from the Port Kennedy bone deposit. Proceedings of the Academy of Natural Sciences of Philadelphia 48: 378–394.

Eshelman, R. E., C. J. Bell, R. W. Graham, H. A. Semken, Jr., C. B. Withnell, S. G. Scarpetta, H. F. James, S. J. Godfrey, J. I. Mead, J.-P. Hodnett, and F. V. Grady. 2025. Middle Pleistocene Cumberland Bone Cave Local Fauna, Allegany County, Maryland: a systematic revision and paleoecological interpretation of the Irvingtonian, Middle Appalachians, USA. Smithsonian Contributions to Paleobiology 108.

Fremd, T. J. 2010. SVP Field Symposium 2010: John Day Basin Field Conference. Society of Vertebrate Paleontology.

Gidley, J. W. 1913. Preliminary report on a recently discovered Pleistocene cave deposit near Cumberland, Maryland. Proceedings of the United States National Museum 46: 93–102.

Merriam, J. C., C. Stock, and C. L. Moody. 1916. An American Pliocene bear. University of California Publications, Bulletin of the Department of Geology 10(7): 87–109.

Mychajliw, A. M., T. C. Rick, N. D. Dagtas, J. M. Erlandson, B. J. Culleton, D. J. Kennett, M. Buckley, and C. A. Hofman. 2020. Biogeographic problem-solving reveals the Late Pleistocene translocation of a short-faced bear to the California Channel Islands. Scientific Reports 10: article 15172. doi: https://doi.org/10.1038/s41598-020-71572-z

Scott, W. B., and G. L. Jepsen. 1936. The mammalian fauna of the White River Oligocene. Part I. Insectivora and Carnivora. Transactions of the American Philosophical Society 28(1): 1–153.

Wang, X., R. J. Emry, C. A. Boyd, J. J. Person, S. C. White, and R. H. Tedford. 2023. An exquisitely preserved skeleton of Eoarctos vorax (nov. gen. et sp.) from Fitterer Ranch, North Dakota (Early Oligocene) and systematics and phylogeny of North American early arctoids (Carnivora, Caniformia). Journal of Vertebrate Paleontology 42: 1–123. doi: https://doi.org/10.1080/02724634.2022.2145900