Titanosaurs: The Surprising Success Story of Long-Necked Dinosaurs
You’re probably familiar with classic sauropod dinosaurs – the four-legged herbivores famous for their long necks and tails. Animals such as Brachiosaurus, Apatosaurus, and Diplodocus have been standard fixtures in science museums since the 1800s. With their small brains and enormous bodies, these creatures have long been the poster children for animals destined to go extinct. But recent discoveries have completely rewritten the doomed sauropod narrative.
The Rise of Titanosaurs
Titanosaurs, a lesser-known group of sauropod dinosaurs, have emerged as a surprising success story in the world of paleontology. Unlike their more famous cousins, titanosaurs flourished long after other sauropods vanished. They not only survived but thrived amid the newly evolved duck-billed and horned dinosaurs, until an asteroid struck Earth and ended the age of dinosaurs.
The secret to titanosaurs’ remarkable biological success may lie in their ability to merge the best characteristics of reptiles and mammals, forming a unique way of life.
Moving with the Continents
Titanosaurs originated during the Early Cretaceous Period, approximately 126 million years ago when many of the Earth’s landmasses were much closer together than they are today. Over the next 75 to 80 million years, as the continents slowly separated, titanosaurs drifted along with the changing formations, becoming distributed worldwide.
There were nearly 100 species of titanosaurs, making up more than 30% of known sauropod dinosaurs. They varied greatly in size, from the largest known sauropods like Argentinosaurus, Patagotitan, and Futalognkosaurus, weighing over 60 tons and bigger than a semitruck, to smaller species like Rinconsaurus, Saltasaurus, and Magyarosaurus, which were around 6 tons and about the size of an African elephant.
Babies to Titans
Like many reptiles, titanosaurs began life comparatively tiny, hatching from eggs no bigger than grapefruits. The best data on titanosaur nests and eggs comes from a site in Argentina called Auca Mahuevo, featuring 75 million-year-old exposed rocks. The site contains hundreds of fossilized nests containing thousands of eggs, some of which are so well-preserved that scientists have recovered skin impressions from ancient embryos.
The close proximity of the nests, found in multiple geological layers, suggests that titanosaurs returned to this site repeatedly to lay their eggs. Titanosaurs likely had a hands-off parenting style, similar to many reptiles that lay numerous eggs and don’t spend much time tending the nest or taking care of hatchlings.
A titanosaur hatchling would have been roughly 1 foot tall, 3 feet long, and weighed 5-10 pounds. Recent evidence from a site in Madagascar suggests that these tiny titans were born ready to rumble. Fossilized bones from the species Rapetosaurus indicate that by the time they would have been just knee-high to a modern human, they were likely fending for themselves. Baby Rapetosaurus likely foraged independently for plants and moved much more nimbly than their lumbering adult relatives.
Rapid Growth Rates
For a long time, paleontologists imagined titanosaurs as giant, overgrown reptiles with slow growth rates. However, new evidence suggests otherwise. Scientists studying titanosaurs’ bones at high magnification have discovered that their growth rates were on par with mammals like whales, much faster than any living reptile. This means that titanosaurs would have reached their enormous adult sizes in just a few decades.
Fueled by Plants
The rapid growth rates of titanosaurs were partly due to their body temperatures. By studying the chemistry of fossilized teeth and eggshells, scientists have determined that titanosaurs had body temperatures ranging from about 95 to 100.5 degrees Fahrenheit. This is higher than that of crocodiles and alligators, about the same as modern mammals, and slightly lower than most birds.
Titanosaurs’ rapid growth rates were also powered by their prodigious appetites for plants. Microscopic patterns on their teeth indicate that titanosaurs in Argentina fed on a diverse diet rich in grit, suggesting they dined on plants found lower to the ground. In India, fossilized feces, known as coprolites, show that titanosaurs ingested everything from ground-level plants to leaves and branches of trees.
The End of an Era
Had it not been for the asteroid impact 66 million years ago, titanosaurs would have continued to thrive in places as distant as Madagascar, Romania, North America, and even Antarctica. Unfortunately, they were among the victims of the most recent mass extinction on Earth.
The story of titanosaurs is a testament to their remarkable adaptability and resilience. These long-necked dinosaurs defied the odds and became one of the most successful