Guest Video: Redwood National Park


So how’s your week going? Ready for a break?

Let’s go for a walk in the park and meet some BIG trees and the wildlife that lives among them.



What most of us don’t realize is that this isn’t just a forest of giants–it’s the last remnant of a biome that once covered western North America until Earth’s climate changed back in the Miocene, a few million years after the continent’s “cat gap” ended.

I came across this while researching the cat book series (emphasis added):

Subsequent to 15 Ma [million years ago], the West began to aridify, and the forests gradually shifted coastward . . . A few remnant species from the Miocene forests still remain in the modern coastal regions of California (e.g., the northern California sequoias), but they have been eliminated from inland regions. The Miocene deciduous forests did not disappear rapidly but slowly declined. A significant drop in warm season temperature occurred around 13 Ma, and the first signs of seasonal drought in the growing season appear in leaf assemblage analyses in the early late Miocene (circa 10–11 Ma) . . .

— Lyle et al., “Pacific Ocean and Cenozoic evolution of climate


Featured image: 12019 at Pixabay. Public domain.


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“False” sabertooths and real sabercats


Fact: Before sabercats, there were sabertoothed cat-like apex predators called barbourofelids and nimravids.


Does it matter if the ferocious sabertooth that’s about to attack you lacks the right bone structure to convince scientists it’s a cat?

Only if you are a paleontologist or other expert in ancient life.

As for the rest of us, luckily, time has made us secure against all things sabertooth. We can safely check out the three major long-toothed “cat” groups that have terrorized the planet at various times since the dinosaurs went away.

1. Machairodontinae

Paleontologists classify sabercats as Machairodontinae – “Knife-Tooths.” (Antón; Turner and others)

That reconstructed cat up above is Smilodon fatalis, the famous sabertooth from California’s La Brea “tar” pits.

Unlike the other Ice-Age sabercat – Homotherium – Smilodon was strictly a New World animal. (Antón; Hulbert and Valdes)

As a group, Knife-Tooths were very successful, with a run of at least twelve million years before they finally disappeared at the end of the last ice age. (Agustí and Antón; Antón; Turner and Antón)

2. Barbourofelidae

The terrifying skull, lower right, is a head shot of Barbourofelis fricki.

It was the last, and biggest, of a long line of cat-like “false” sabertooths that lived in Europe, Asia, Africa, and North America during the second half of the Miocene epoch. (Antón; Bryant)

Barbourofelids were apex predators that the first true cats had to face while the cat family Felidae quietly evolved in the bushes and forest canopies of Europe.

Barbourofelid saberteeth were very real. It’s their connection to the cat family that paleontologists aren’t sure of.

Barbourofelids were short-faced hypercarnivores similar to true cats, with much the same build. (Antón; Werdelin and others)

However, their fossils are just different enough from cats for experts to keep them in a separate family for now. (Bryant; Werdelin and others)

3. Nimravidae

Those saberteeth shown on the lower left – belonging to Eusmilus cerebralis – would be impressive if they weren’t in such a picture.

But imagine a large housecat with them. Yikes!

That’s roughly how big E. cerebralis was. (Antón)

Eusmilus and other nimravids, some of which were very large, are the second and earlier group of “false” sabertooths.

In many ways, nimravids outdid the true sabercats. Besides having big sabers in very small animals, which never happened in cats, several of the complex cranial and body anatomy features that support a sabertooth lifestyle were also more advanced. (Werdelin)

That’s strange, because nimravids are very old. So old that the continents were in a slightly different configuration in their day. (Antón; Bryant; Agustí and Antón; Prothero; Werdelin and others)

In the fossil record, five to ten million years separate the last nimravid and the first barbourofelid. (Antón)

That’s the last nimravid.  No one knows how or when nimravids developed into Earth’s very first cat-like predators.

Their oldest fossils go back at least thirty-five million years, but according to some research, the group may be at least fifteen million years older than that. (Averianov and others; Peigné)

So here we are today.  It’s very cool that predators have had a feline appearance for tens of millions of years.

Which one was the biggest and baddest: true cats or one of the “false” sabertooths?

Well, each group was big and bad enough to dominate its ecosystem.  Unfortunately, scientists still know very little about the complex environments that barbourofelids and nimravids lived in.

That leaves us with just a human scale to measure these predators with – and when it comes to love and a sort of fearful fascination, Smilodon wins paws down.

How else could this happen?


IMAGES:
Featured image:

    • Barbourofelis fricki, Museo di Paleontologia di Firenze: Ghedoghedo. CC BY-SA 3.0. Modified by Barb Beier.
    • Eusmilus cerebralis (olsontau), Dallas Krentzel. CC BY 2.0.

 

 


CITED AND UNCITED REFERENCES:

Agustí, J. and Antón, M. 2002. Mammoths, sabertooths, and hominids: 65 million years of mammalian evolution in Europe. New York and Chichester: Columbia University Press.

Antón, M. 2013. Sabertooth. Bloomington:Indiana University Press.

Averianov, A.; Obraztsova, E.; Danilov, I.; Skutschas, P.; and Jin, J. 2016. First nimravid skull from Asia. Nature, Scientific Reports. doi:10.1038/srep25812.

Barrett, P. Z. 2016. Taxonomic and systematic revisions to the North American Nimravidae (Mammalia, Carnivora). PeerJ. 4:31658. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4756750/ Last accessed August 28, 2017.

Bryant, H. N. 1991. Phylogenetic Relationships and Systematics of the Nimravidae (Carnivora). Journal of Mammalogy, 72(1):56-78.

Gradstein, F. M.; Ogg, J. G.; and Hilgen, F. G. 2012. On the geologic time scale. Newsletters on Stratigraphy. 45(2):171-188.

Heske, E. J. Fall 2013 semester. Mammalogy 462, online class notes. Multiple lectures. http://www.life.illinois.edu/ib/462 . Last accessed December 11, 2015.

Hulbert, Jr., R. C., and Valdes, N. 2015. Smilodon fatalis. Florida Museum, University of Florida. https://www.floridamuseum.ufl.edu/florida-vertebrate-fossils/species/smilodon-fatalis/ Last accessed August 28, 2017.

Peigné, S. 2003. Systematic review of European Nimravinae (Mammalia, Carnivora, Nimravidae) and the phylogenetic relationships of Palaeogene Nimravidae. Zoologica Scripta. 32(3):199-299.

Prothero, D. R. 2006. After the Dinosaurs: The Age of Mammals. Bloomington and Indianapolis : Indiana University Press.

Turner, A., and Antón, M. 1997. The Big Cats and Their Fossil Relatives: An Illustrated Guide to Their Evolution and Natural History. New York: Columbia University Press.

Turner, A., Antón, M., Salesa, M. J., and J. Morales, J. 2011. Changing ideas about the evolution and functional morphology of Machairodontine felids. Estudios Geológicos. 67(2): 255-276.

Werdelin, L. 1996. Carnivoran Ecomorphology: A Phylogenetic Perspective, in Carnivore Behavior, Ecology, and Evolution, ed. Gittleman, J. L., 2:582-624. Ithaca, NY: Cornell University Press.

Werdelin, L.; Yamaguchi, N.; Johnson, W. E.; and O’Brien, S. J.. 2010. Phylogeny and evolution of cats (Felidae), in Biology and Conservation of Wild Felids, ed. D. W. Macdonald and A. J. Loveridge, 59-82. Oxford: Oxford University Press.

Wright, M., and Walters, S. 1980. The Book of the Cat New York: Summit Books.