Two New Studies of Sabertooth (Smilodon fatalis) Anatomy

Artist’s rendition of saber-tooths from google images.  The San Diego MNH warned me that I couldn’t use theirs.  This one is better anyway.  The San Diego MNH can kiss my ass.

In 1973 a Time Magazine article sparked my fascination with Pleistocene ecology.  The article was entitled “Tiger in the Bank,” and was about the discovery of Pleistocene fossils during construction of the First National Bank in Nashville, Tennessee.  Construction workers leveled 4 small Indian mounds and dug 30 feet deep into the ground to lay the foundation for the future skyscraper.  They used dynamite and heavy moving equipment to blast and dig through limestone and dirt.  An alert  worker discovered a saber-tooth tiger fang and haulted construction.   Bob Ferguson, a local fossil hunter, and scientists from Vanderbilt University  began excavating the site and found bones from many different species of Pleistocene and contemporary animals which I list below.  The carbon date on the saber-tooth bones piqued my then grade school imagination –it was estimated to be just 9,410 years old.  To me, 9400 years didn’t seem that long ago, especially compared to dinosaurs which are all at least 65 million years old.  It amazed me that something so exotic ranged through Tennessee so recently.  Since then, scientists, armed with advances in knowledge and techniques of carbon dating, no longer trust carbon dates derived in the early 1970′s.  Moreover, it’s now known those dates when adjusted to tree ring chronology were too young.  Today, a date of 9400 years is adjusted to 10,200 calender years.  The carbon date done in 1973 simply means the saber-tooth was at least 9400 years old, and a good terminal date on Smilodon doesn’t exist.  Still, after considering the low odds of a living animal becoming a fossil specimen, I think it’s probable saber-tooth populations survived somewhere  until between 6,000-9,000 years ago, although their decline in numbers began well before them.  The late Dr.  Guilday, the scientist who examined the saber-tooth bones found at this site, did test it for organic matter, and it proved fresh, supporting the recent date.  The bone still consisted mostly of organic matter and didn’t have a lot of permineralization yet.

Smilodon jaw and muscle diagram from google images.

New discoveries of Smilodon fossils are rare.  But thanks to abundant fossil material found at the La Brea Tar Pits, scientists are able to study its anatomy in detail.  The 2 new studies yield nothing surprising or contrary to expectation. The first study (“A Dynamic Model for the Evolution of Sabercat Predatory Bite Mechanics” by Per Christiansen) examined saber-tooth bite mechanics.  Saber-tooths are known to have had weak biting power compared to other carnivores.  Instead, they used their powerful neck muscles to thrust their long canine fangs forward into the neck of their prey.  Their jaw muscles were shortened and more specialized for inflicting traumatic damage and immediate mortality.  Unlike extant cats, they didn’t suffocate their prey with time-consuming throat bites which would increase the probability that struggling prey would damage their fangs.  They efficiently severed jugular and windpipe with one quick bite.

Smilodon arm bones from google images.

The second study (“Radiographs Reveal Exceptional Forelimb Strength in the Saber-tooth Cat, Smilodon fatalis” by Julie Meacham-Samuels, et. al.) calculated the arm strength of Smilodon and compared it to that of 29 other species of cats.  They measured the size of different parts of the arms based on radiographs and used 5 different formulas derived from basic laws of physics including this one: Axial Compression = pye (external caudal diameter) (external medialateral diameter)-(diameter of medullary cavity) (medialateral diameter of medullary cavity)/4.   They determined that saber-tooth arm strength far surpassed that of any living cat or even the larger extinct giant panther aka the American lion (Panthera atrox).  Not only were they naturally stronger, but wrestling with large prey built up strength, much like humans  use weight training to increase muscle mass and strength.  Experienced saber-tooths would be much stronger than those first learning to hunt on their own.  The authors of the study found that greater forelimb strength co-evolved with lengthened canines in other species as well.  It was critical for carnivores with long fangs to quickly subdue prey to reduce the risk of damage to their canines.

References:

Christiansen, Per

“A Dynamic Model for the Evolution of Saber-cat Predatory Bite Mechanics”

Zoological Journal of the Linnean Society 162 (1) May 2011 220-242

Meacham-Samuels, Julie; Blaine Van Valkenburgh, Allen Fork

“Radiographs Reveal Exceptional Forelimb Strength in the Saber-tooth, Smilodon fatalis”

Plosone 5 (7) 2010

See also my article “Why did Fanged Cats have Long Forelimbs and Sloping Backs?” from my October 2010 archives

The First National Bank Fossil Site

Photo from wikipedia of display case in the Regions Bank Center, Nashville, Tennessee, which sits on top of a Pleistocene fossil site.  These are replicas.  Officials don’t know who has the real fossils that were found at this site.

10,000 years ago, a shaft leading to a limestone cave acted as a trap for many species of animals which either fell or crawled inside and died.  Eventually, this cave filled with mud and became covered with sediment.  The shaft periodically became exposed to the surface during the Woodland Indian era of 2000 years BP, and even during Colonial times.  The Indians built 4 small mounds here.  In 1971 executives from First National Bank chose to build a skyscraper at this location.  Construction workers used dynamite to blow up the limestone rock.  Backhoes removed the fill.  One worker saw a “saber-tooth tiger” canine and haulted construction.  As I stated above, Bob Ferguson and scientists from Vanderbilt excavated what was left of the cave.  Most of the fossils they found were actually in the spoil piles that had already been removed.  Fossils and artifacts from 3 different eras were mixed in the spoil piles, ruining the chronostratigraphy.  They found fossils of colonial era livestock, mixed in with the remains of 4 buried Indians, and Pleistocene fossils.  Regions bank merged with First National Bank, but they still keep a display case of replica fossils.  Officials don’t know who has possession of the original fossils.  Bank officials claim they sent the fossils to the Smithsonian Institution.  The Smithsonian Institution claims they never received them.  If anybody knows who has possession of them, please respond to this article and tell us.

The remains of the cave still exist and can be accessed via a hatch under the basement of the skyscraper.  Reportedly, cavers who revisited the site in 2008 were unimpressed.  The archaeologist who wrote the newspaper article about this cave expedition that  was published in The Tennessean was sadly misinformed when he stated that saber-tooths didn’t overlap in time with humans. Here’s the list of fossils found at the site:

# denotes fossils were found from remnant Pleistocene strata

# Fish scales sp.?

Toad sp.?

mud turtle

water snake

garter snake

#black racer

#northern pine snake

milk snake

#rattlesnake

coot

opossum

least shrew

short-tailed shrew

eastern mole

#cottontail rabbit

swamp rabbit

squirrel sp.?

pocket gopher

deer mouse

pine vole

canis sp.?

bobcat

#saber-tooth–119 fragmented teeth and bones of 1 individual.  A canine was intact.  Bones were relatively fresh with little permineralization

raccoon

striped skunk

#mastodon–a baby tooth

#horse–more than 1 individual.  Some may be mixed in with colonial era material

domestic hog

deer sp.?

#musk ox sp.? –probably woodland musk-ox.  Just a phalanx.

long-nosed peccary

human

Reference:

Guilday, J.E.

“Saber-tooth cat, Smilodon floridanus, and associated fauna from a Tennessee Cave (40Dv40), the First American Bank Site”

Journal of Tennessee Academy of Science 52 (3): 84-94

Available online–http://iweb.tntech.edu/sstedman/JTAS%2052-3.pdf

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6 Responses to “Two New Studies of Sabertooth (Smilodon fatalis) Anatomy”

  1. James Robert Smith Says:

    It’s horrifying to me that as late as the 1970s we allowed Indian mounds to be leveled for a freaking modern building.

    And, yeah…screw the San Diego MNH.

    I actually wasn’t aware that the smilodon ranged here in the south. I’d thought of it as a purely western species. I’ve read that they did not go extinct until 8K years or so ago. From looking at the evidence, it’s obvious to me that Native Americans were instrumental in killing off most of the megafauna of North America. Just as the Aborigine did the same in their march across Australia from west to east, eating everything in their wakes.

    A lot of people have a hard time accepting this, seeing Indians and Aborigines in the racist light as the good folk living in harmony with Nature. Alas, it’s just not true. They both strode across their respective continents, slaughtering everything in sight that could not adapt quickly.

    • Robin Burkhalter Says:

      @James Robert Smith:

      Its interesting that you would be so objective about Amerindians seeing that any attempt at being honest about who they really were, warts and all, is viewed as racist and ethnocentric. Not that I approve of how Europeans treated them, but in many ways it was no different than how Native Americans had been treating each other for millenia. Even into the 1800s all atrocities against natives weren’t solely committed by Europeans, and any attempts to portray white men as “evil” and natives as “pure” is quite simply revisionist history.

  2. markgelbart Says:

    Smilodon fossils are actually quite commonly found in Florida. A few have been discovered in northern Alabama, and South Carolina as well.

  3. Mark LaRoux Says:

    Great article Mark, and as you said smilodon were found in north Alabama as well as at least 1 kind of jaguar and cougar. I’d argue that feline diseases/conflict were just as hard on the cats as the natives over millenia. We may have administered the final coup de grace, but weren’t around them enough to kill most of them. We tend to forget this biogeographical issue when we keep our pets immunized, indoors, and bred for tolerance.aguar and cougar. I’d argue that feline diseases/conflict were just as hard on the cats as the natives over millenia. We may have administered the final coup de grace, but weren’t around them enough to kill most of them. We tend to forget this biogeographical issue when we keep our pets immunized, indoors, and bred for tolerance.

  4. Pleistocene Fossil Felid Ratios from the University of Florida Database « GeorgiaBeforePeople Says:

    [...] “Two new studies of saber-tooths.”– https://markgelbart.wordpress.com/2011/07/08/two-new-studies-of-sabertooth-smilodon-fatalis-anatomy/ [...]

  5. The inverted Adam Smith « Hedfulofspidrs Says:

    [...] Our early forebears may well have endured remarkable hardships, but I imagine they would have chosen their lifestyles above ours. After all – who wants to spend eighteen hours a day gold farming or mass producing footwear when you could be wrestling an enraged smilodon fatalis instead? [...]

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