If remains of baby Titanosaur is anything to go by, they probably were almost independent from the moment they were born.
Long-necked sauropod dinosaurs include the largest animals ever to walk on land, but they hatched from eggs no bigger than a soccer ball.
Research funded by the National Science Foundation (NSF) and led by Kristi Curry Rogers of Macalester College in St. Paul, Minnesota, sheds the first light on the life of a young Rapetosaurus, a titanosaurian sauropod buried in the Upper Cretaceous Maevarano Formation of Madagascar.
The baby behemoths were active, capable of a wider array of maneuvers than adult members of their species, and didn't need parental care after hatching.
"These scientists employed several lines of evidence to investigate growth strategies in the smallest known post-hatching sauropod dinosaur," said researcher Judy Skog.
Skog said the researchers developed tests that could be applied to other perinatal dinosaurs.
The preserved partial skeleton was so small that its bones were originally mistaken for those of a fossil crocodile, said Curry Rogers.
"This baby's limbs at birth were built for its later adult mass; as an infant, however, it weighed just a fraction of its future size," Curry Rogers said. "This is our first opportunity to explore the life of a sauropod just after hatching, at the earliest stage of its life."
"We looked at the preserved patterns of blood supply, growth cartilages at the ends of limb bones, and at bone remodeling," Curry Rogers said. "These features indicate that Rapetosaurus grew as rapidly as a newborn mammal and was only a few weeks old when it died."
The tiny titanosaur was mobile at hatching and less reliant on parental care than other animals. Baby sauropods like Rapetosaurus were somewhat like miniature adults, Curry Rogers said.
When taken in the context of the intensely drought-stressed ecosystem represented in the Maevarano Formation, it's clear that this Rapetosaurus had it rough, Curry Rogers said.
The findings are published in the journal Science.