Ok. No more movie voice. But where did the large sauropod Camarasaurus roam? A new paper in Nature may be closer to discovering the truth.

Scientists believe that some dinosaurs migrated seasonally for food, and now Henry Fricke and his colleagues at Colorado College may have the evidence—thirty-two Camarasaurus teeth.

Camarasaurus were enormous. With an average length of 50 feet, they ate about twice as much as today’s modern elephants—almost 1,000 pounds of food each day! As Fricke told Nature News,

They are huge—they would probably have eaten themselves out of house and home if they stayed in one place.

According to the fossil record, Camarasaurus inhabited the dry plains of western North America. The teeth the researchers sampled were all found in Wyoming and Utah, where the ancient seasonality record is pretty clear. ScienceNOW explains:

During the wet season, the prehistoric lowland basins of Wyoming and eastern Utah were flat, open habitats carpeted with ferns and stands of conifers. The researchers propose that the dinosaurs left this area at some point during the year, probably during the dry season, when the smorgasbord of tasty plants closed.

How did the researchers extract the evidence of movement from the Camarasaurus teeth? By measuring the ratio of isotopes within the enamel, New Scientist explains.

The ratio of isotopes is determined by the water the dinosaurs drank. [Fricke] found the ratio in teeth was different to that in carbonate rock from the floodplain—which carries the signature of the water it formed in. This suggests that Camarasaurus sometimes left the area.

Fricke and his team suspect the dinosaurs headed to higher, wetter ground seasonally, when the plains were dry, possibly traveling up to 180 miles.

The team plans to sample the teeth of other dinosaur species next. They have a hunch that where the herbivores traveled, the carnivores were close behind.

Image credit: Dmitry Bogdanov/Wikipedia

Paleontologists mapped several egg clutches in the Sanagasta Valley in La Rioja province, northwestern Argentina last summer and found that certain dinosaurs returned again and again to the same nesting site. The reason seems to be the warm geothermal vents that existed there during the Gondwanic hydrothermic cycle—134 to 110 million years ago.

According to their paper, published June 29^th in Nature Communications,

Sedimentary and geochemical analyses of 80 clutches and their large eggs with thick eggshells substantiate that the Sanagasta sauropods were specifically using the soil moisture and thermoradiance to incubate their eggs.

An article in Nature suggests that the eggs evolved to withstand such harsh conditions during incubation:

The team found that the eggs were large and thick-shelled when freshly laid, an adaptation that may have evolved to allow them to safely incubate in the acidic environment near geyser fountains.

The researchers have yet to determine the species of sauropods that the eggs belonged to, only noting that it belonged on the branch of neosauropods. According to the “Not Exactly Rocket Science” blog from Discover:

Each huge egg measured around 21 centimetres in diameter… They are so big and thick that they must have been laid by very large animal indeed, probably one of the giant sauropods. Unfortunately, no skeletons have actually been found so Grellet-Tinner and Fiorelli [the paleontologists] can’t tell us what species laid these eggs. Whatever they were, they clearly laid their eggs in the valley repeatedly and en masse, forming a long-lasting relationship with this special place.

Currently, only an endangered turkey found in Tonga, a type of megapode, has similar egg-laying behavior. They lay their eggs in volcanically heated burrows.

Image credit: Gerald Grellet-Tinner/Lucas Fiorelli

But what would it take to satisfy the appetite of the largest terrestrial animal that ever lived? Weighing ten times more than an elephant, how did it have enough time to eat in a day?

For the first time, new research is offering a plausible answer to the question that’s long riddled paleontologists: how were giant long-neck dinosaurs even able to exist?

According to an abstract published last month in Biological Reviews, “The herbivorous sauropod dinosaurs of the Jurassic and Cretaceous periods were the largest terrestrial animals ever, surpassing the largest herbivorous mammals by an order of magnitude in body mass.”

“They were just so large that a day would have had to have 30 hours so that they were able to meet their energy demands,” explains lead author Professor Martin Sander from the University of Bonn in Germany.

So how did sauropods manage with only 24 hours? According to the study, it’s all about evolutionary efficiency. And, don’t tell your mother, but these large dinos didn’t chew their meals, they gulped.

Chewing requires time and a large head, since molars and jaw muscles have to be put somewhere. However, the herbivorous giant dinosaurs had relatively small, light skulls. This meant that sauropods were able to grow extremely long necks, allowing them to make food intake as efficient as possible. They did not constantly have to heave their 80-ton body over the Jurassic savanna while looking for their greens.

Horsetails were part of the sauropods’ diet. According to Sander and his team, they are exceptionally nutritious. But only a few animals feed off them today because presumably, horsetails are bad for the teeth. They contain a lot of silica, which acts like sandpaper.

The digestion process itself probably took several days but their stomachs were so large that they still provided them with enough energy round the clock. Moreover, the metabolism of these giant animals was incredibly powerful. They possessed amazingly sophisticated lungs, which were far more effective than those of humans.

The combination of these traits allowed the sauropods to live successfully with a “fast food” diet.

Creative Commons image by DiBgd