While it is impossible to know everything about a creature that lived 70 million years ago, U-Haul contacted Bob Farrar, one of the owners of the Black Hills Institute of Geological Research, to help answer a few questions that came up while researching the mysterious Archelon...
U-HAUL: What distinct, physical characteristics
set the Archelon apart from other sea turtles of the time?
Bob Farrar: The Archelon's size definitely
set it apart from other sea turtles. The structure of the carapace, the
upper part of the shell that covers the turtle's back, had an advanced
design that kept bone mass to a minimum. There are large holes through
the Archelon's shell, which allowed its body to grow much larger than
other turtles, but weigh less.
U-HAUL: If the Vienna specimen of
Archelon was hibernating on the sea floor when it died, how did it breathe?
Bob Farrar: Actually, the correct term
is brumating.
When turtles brumate, they go into a very low metabolic state, which allows
them to sleep on ocean floor for long periods of time. The Archelon was
an air-breathing creature, so when it needed to breathe, it would wake
up and swim to the surface for air.
U-HAUL: Was the Archelon able to retract
its head, legs and tail into its shell? If not, why?
Bob Farrar: No. Archelons, like modern
sea turtles, are unable to go into their shell. Tortoises and land turtles
can withdraw into their shells because their shell is solid and shaped
differently than a sea turtle's shell.
U-HAUL: Approximately how many Archelons
roamed the earth during the Cretaceous period?
Bob Farrar: There is no way of knowing
for sure, but I can tell you that the highest number of Archelon skeletons
have been discovered in South Dakota.
U-HAUL: How many Archelon skeletons
have been found in South Dakota?
Bob Farrar: Seven or eight, but only
two or three of these specimens were relatively complete.
U-HAUL: What did the Archelon eat,
and how do you know this?
Bob Farrar: It probably fed partially
on mollusks and maybe squid. The shape of the roof of its mouth is arched,
which would have created suction. Animals like mollusks and squid would
be easily sucked into its mouth. It's also likely that the Archelon may
have eaten some plants because virtually all living sea turtles today
feed on living plants.
U-HAUL: What was the average life
span of the Archelon?
Bob Farrar: I'm not sure, but I'd guess
50 to 100 years.
U-HAUL:
Which prehistoric creatures were Archelon's predators?
Bob Farrar: Other large creatures of
the time, like mosasaurs,
which were 40-foot-long relatives of the monitor lizard, but they were
strictly marine. There were pleisosaurs, sharks and some fish that would
have been large enough, like the xiphactinus. Xiphactinus was an 18-foot
fish with three-inch teeth.
U-HAUL: Was the Archelon a graceful
creature?
Bob Farrar: Yes. I think it was fairly
graceful in the water. Most marine animals are pretty graceful. Out of
the water, however, I'm sure it was pretty clumsy.
U-HAUL: What's the difference between
a turtle and a tortoise?
Bob Farrar: Through evolution, tortoises
have developed specializations that have restricted them, making them
primarily land-dwellers. Turtles are far more aquatic animals.
U-HAUL: What characteristics of the
Archelon are similar to the modern-day Leatherback Sea Turtle?
Bob Farrar: The reduction of the bones
in the shell. Also, the Leatherrback gets quite large. Not a tremendous
amount of information is known about either one of them.
U-HAUL: Did the Archelon spend any
time on land or was it strictly a marine turtle?
Bob Farrar: It was a marine animal.
It may have nested on beaches, but out of water it really couldn't move
much because its legs were flippers not adapted to moving on land.
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The Cretaceous Period: Age of Reptiles
