My primarily research is on fossil mammals after the extinction of the dinosaurs.

These are my major active research projects that I’m seeking funding and students for:

What happens to mammals during global warming events?

Piceance Creek Basin, Colorado

Within the Paleocene and Eocene strata of the Piceance Creek Basin of Western Colorado I’ve collected fossil mammals straddling the Paleocene-Eocene boundary. During this boundary between epochs 55.6 million years ago was a remarkable global warming event, called the PETM (Paleocene-Eocene Thermal Maximum). The event also marks a remarkable extinction event for arboreal mammals (like primates), indicating extreme deforestation, and a changing flora. This research was the subject of my PhD dissertation and I continue to work on the paleontology and geology of the basin.

Publications from this Research

Burger, B.J. 2013. A new species of the archaic primate Zanycteris from the late Paleocene of western Colorado and the phylogenetic position of the family Picrodontidae. PeerJ 1:e191;DOI 10.7717/peerj.19 [LINK]

Burger, B.J. 2012. Northward range extension of a diminutive-sized mammal (Ectocion parvus) and the implication of body size change during the Paleocene-Eocene Thermal Maximum. Palaeogeography, Palaeoclimatology, Palaeoecology 363-364:144-150. [LINK]

Burger, B.J. 2009. Mammalian faunal change across the Paleocene-Eocene boundary in the Piceance Creek Basin, western Colorado. Unpublished PhD dissertation, University of Colorado, Boulder. pp. 834. [LINK]

Burger, B.J. and Honey, J. 2008. Plesiadapidae (Mammalia, Primates) from the Late Paleocene Fort Union Formation of the Piceance Creek Basin, Colorado. Journal of Vertebrate Paleontology 28(3):816-825. [LINK]

Burger, B.J. 2007. A new late Paleocene vertebrate fauna from the Ohio Creek Formation of western Colorado. The Mountain Geologist, vol 44, No. 3 pp. 41-51. [LINK]


Rock samples collected from the Middle Eocene Duchesne River Formation in Utah.

How did dogs, cats, horses and deer evolve during the Eocene Epoch? And why did all the primates disappear from North America during the same time?

In the Eocene Duchesne River Formation in Northeastern Utah, I am working toward locating another significant global warming event that occurred 40 million years ago, called the Middle Eocene Climate Optimum. I’ve been utilizing carbon isotopes left in the rocks to use as a proxy and hope to correlate the formation to ocean sediment cores. Fossil mammal teeth are rare in the formation, but continued sampling has produced some results of this critical time in Earth’s History. In the last several years I’ve discovered new localities of fossil mammals, that are helping to fill in a gap in our knowledge of the evolution of mammals in North America.

Publications from this Research:

Burger, B.J., 2015. Carbon Isotope Stratigraphy of the Late Middle Eocene Duchesne River Formation in the Uinta Basin of Northeastern Utah, in Vanden Berg, M.D., Ressetar, R., and Birgenheier, L.P., (eds.) Geology of Utah’s Uinta Basin and Uinta Mountains: Utah Geological Association Publication 44, p. 109–118. [LINK]

Burger, B.J. 2015. The systematic position of the Middle Eocene Leptotragulus from Utah and  the timing of the origin of Ruminant Artiodactyls in North America. Tate Geologic Museum, Casper College

Burger, B.J. and Tackett, L. 2014. The Stratigraphic Importance of the Brontothere (cf. Diplacodon elatus) in the Brennan Basin Member of the Duchesne River Formation of Utah. Fossil Record 17:69-74. DOI: 10.5194/fr-69-2014 [LINK]

Burger, B.J. 2011. Fossil mammals from the late Eocene Brennan Basin Member of the Duchesne River Formation in Utah. Rocky Mountain 63rd Annual and Cordilleran 107th joint meeting, Geological Society of America Abstracts 43:78 [LINK]

What fossils are still hidden in the Badlands of western North America?

In a remote region of Wyoming, I’ve been collecting fossil mammals from the Eocene Washakie Formation, famous for the remarkable Dinocerata “terrible horned” beasts, such as Eobasileus, Tetheopsis, and Uintatherium shown below. The Washakie Formation also preserves a boundary between the Bridgerian and Uintan Land Mammal Ages, representing a remarkable shift in mammals that may indicate a significant drying climatic event, around 46 million years ago.

Looking for tiny fossil mammal teeth in the Washakie Basin of Wyoming

Looking for tiny fossil mammal teeth in the Washakie Basin of Wyoming

Skull of Uintatherium a typical Dinocerata from the Washakie Basin.











Publications from this Research

Burger, B.J. 2016. Hyrachyus eximius from the Middle Eocene lower Washakie Formation Abode Town Member of Wyoming and its bearing on the origin and early diversification of rhinoceroses. Presented at the Utah Friends of Paleontology annual meeting in Moab, Utah

Burger, B.J. 2015. The systematic position of the saber-toothed and horned giants of the Eocene: the Uintatheres (Order Dinocerata).Presented at the Society of Vertebrate Paleontology meetings Dallas, Texas