Natural History of Cats
Natural History - American Museum of Natural History
While a Research Associate in the Division of Paleontology, I focused my research on fossil members of the family Felidae (fossil felids, fossil cats). I continue to study primarily the fossil felids of North America, focusing on the specimens present in the Frick-AMNH collection of fossil mammals.
Contact me at:
Paris Hill Cat Hospital
2825 Old Route 12 • Paris, NY 13456
Ph.D., Vertebrate Paleontology
Department of Earth and Environmental Sciences
Lamont-Doherty Earth ObservatoryColumbia University, New York City
Click here to go to Lamont-Doherty Earth Observatory
Doctor of Veterinary Medicine, 1976
New York State College of Veterinary Medicine
Ithaca, New York
Click here to go to Cornell's NYS College of Veterinary Medicine
Bachelor of Science, Chemical Engineering
Syracuse University, 1971
- 2004. Rothwell, T. New felid material from the Ulaan Tologoi locality, Loh Formation (early Miocene) of Mongolia. In G.C. Gould and S.K. Bell (editors), Tributes to Malcolm C. McKenna: his students, his legacy. Bulletin of the American Museum of Natural History 285: 157-165.
- Rothwell, T. 2002. Phylogenetic systematics of North American Pseudaelurus (Carnivora: Felidae). Bulletin of the American Museum of Natural History (In Press)
- Rothwell, T. 2002. New felid material from the Ulaan Tologoi locality, Loh Formation (early Miocene) of Mongolia. Bulletin of the American Museum of Natural History, Number 285 (Chapter 12).
- Rothwell, T. 2001. A partial skeleton of Pseudaelurus (Carnivora: Felidae) from the Nambé Member of the Tesuque Formation, Española Basin, New Mexico. American Museum Novitates 3342:1-31.
- Rothwell, T. 1982. Aerobic and anaerobic conditioning of the three-day event horse. USCTA News June: 6-8.
- Rothwell, T. 1981. The AHSA drugs and medications rule-know your facts, avoid needless elimination. USCTA News April: 20-21.
- Rothwell, T. 1980. Re-training the horse with navicular disease. Long Island Horse World 2:30-31.
- Rothwell, T. 1978a, The tragedy of hip dysplasia. In: Caras, R. (ed.) Dog Owner's Bible, pp.277-280.South Hackensack: Stoeger Publishing Company.
- Rothwell, T. 1978b, The crucial business of immunization. In: Caras, R. (ed.) Dog Owner's Bible, pp.32-38.South Hackensack: Stoeger Publishing Company
I am a student of natural history. I am interested in the anatomy of felids (cats) and how knowledge of this anatomy can lead to understanding evolutionary relationships within the family Felidae, the sub-order Aeluroidea and the order Carnivora. My first body of work at the American Museum, my doctoral dissertation, concentrated on the anatomy of the earliest fossil felids of North America. These cats entered the North American continent approximately 17 million years ago, and left a fossil record that spanned approximately 5 million years. I compared the anatomy of these extinct taxa to modern cats, and then hypothesized on their relationships. As a result of this work, the earliest felids that entered North America now have genus and species names as well as morphological characters that are attached to these names. This is indeed a good start. However, much more needs to be done. For example, it has been published that the felids alive today are closely related and that they share a common ancestor that lived only three or four million years ago. I am interested in investigating whether that is true, and if so, in determining just who that ancestral felid might be.
My present research involves the earliest saber-toothed cats of North America. The first fossil evidence of these special felids, with their elongated upper canines, begins to show up in North American localities approximately 11 million years ago. At the American Museum, we have a magnificent collection of these early saber-tooth cats. I am studying the anatomy of these fossils in great detail and I will be comparing their anatomy with that of the earlier fossil felids and to the cats who are alive today. I will then use computer programs to analyze this data. The computer will provide hypotheses, or suggestions as to the relationships of all of these cats. A scientific goal is to determine who the ancestor of the earliest saber-tooth cats might be.
There is another feline question that I would like to help answer. If all of the cats alive today are closely related (and they appear to be very closely related), then it may be possible to identify their common ancestor in the fossil record. If the common ancestor of today's cats can be identified, perhaps then we can find out why it survived and why other potential ancestors went extinct. If we are to prevent further extinction within the family Felidae; if we wish to save the great cats that are still with us, the lions, the tigers, the snow leopards, surely then we must find out how and why the cats that survived to the present did so.
cladogram: This is a manually constructed cladogram that I use when teaching. It demonstrates the three major clades, or divisions of living families within the order Carnivora. In blue is the large and diverse group known as the arctoids. The canids (dogs, wolves, coyotes, etc,) are represented by a single lineage in green. The cats, hyenas, mongoose and viverrids are the red group known as the aeluroids. Characters 1, 2, and 3 are hypothesized to unite all of Carnivora:
Character 1 is use of the upper fourth premolar (P4) and lower first molar (m1) by all members of the order Carnivora to eat meat. This is called the P4/m1 carnassial apparatus.
Character 2 is near and dear to all veterinarians who practice on dogs and cats. Character 2 is the presence of anal sacs. Anal sacs are hypothesized to be present in the ancestor of Carnivora due to its widespread distribution among all of the living members. Anal sacs are lost or reduced only in bears and in the aquatic families (seals, sea lions, walrus and otters).
Character 3 is the primitive carnivoran dentition: 4 premolars and 3 molars in both the upper and lower dentition.
Character 4 unites all of the living families of Carnivora. Character 4 is the development of an ossified bulla covering the middle ear, a bony covering for the ear apparatus. The primitive carnivorans (carnivoran = member of the order Carnivora) had a single-chambered bulla covered by cartilage.
Character 6 diagnoses the four closely related families referred to as the aeluroids or the sub-order Aeluroidea. Character 6 is a modification of the primitive single-chambered bulla: the development of a two-chambered bulla. Evidence of character 6 can be seen in the ventral skull and in the basicranial photograph.
Data Table Results: There are arguments for and against sexual dimorphism being the explanation for some character differences between species of fossil felids. Arguments for include: (1) Sexual dimorphism is seen in modern felid species, at the very least in body size and skull length in small felids. (2) The fossil felids Pseudaelurus skinneri and Pseudaelurus stouti display differences in c--p3 length that could also be interpreted as sexual dimorphism. (3) The fossil felids Pseudaelurus intrepidus and Pseudaelurus marshi are size and temporally equivalent. Specimens of the two species are sometimes found in the same paleontological localities (quarries). Arguments against include: (1) A similar range in c--p3 length and dentary height and width is not seen in the fossil felid Pseudaelurus validus. Pseudaelurus validus and some modern species do not exhibit sexual dimorphism in the lower jaw. (2)
Stratigraphic Chart: This is a rough estimate of stratigraphic ranges for various fossil felids. As new specimens are discovered, or as fossil localities are dated more precisely, these ranges will change. The first North American felids arrived during a major dispersal from Eurasia to North America that began approximately 20 m.y. ago. The early fossil felid record of Asia is poor. Only a small number of specimens have been recovered from early and middle Miocene localities. Therefore, the stratigraphic range of Pseudaelurus in Asia is less certain than Europe and North America.
My present felid research project is a study of the early North American saber-tooth cats, often referred to as the machairodont felids. Nimravides and Machairodus are two of the earliest North American saber-tooth cats. NA Felis refers to the stratigraphic range of fossils of the modern felids.
From 1932 to 1965, Childs Frick sent numerous collecting parties into the fossiliferous terrestrial localities of Tertiary North America. The Frick Laboratory assembled a magnificent collection of fossil mammals as a result of these expeditions. Now referred to as the Frick Collection, this assemblage of fossil mammals is housed in the collections of the Division of Paleontology of the American Museum of Natural History. Within the Frick Collection is the world's most comprehensive fossil felid collection. Fossils of the first felids to arrive in North America, in the late Hemingfordian, were collected in localities of the Sheep Creek Formation of Nebraska and the Tesuque Formation of New Mexico. The earliest known partial felid skeleton (FAM 62128) was recovered from the Nambé Member of the Tesuque Formation of New Mexico and described by me in 2001. Photo by Chester Tarka of the AMNH.