Sauropods: Not Putting All Their Eggs in One Basket

When you think of enormous dinosaurs, you would expect their eggs to be just as massive. Well, think again. At least for sauropods, their eggs were a lot smaller than anticipated, partly due to the fact that they didn't put all their eggs in one basket.

Though they are the most colossal creatures to ever walk the Earth, sauropods - a suborder of dinosaurs which includes the famous Diplodocus - for a reason unbeknownst to scientists they produced some incredibly small eggs.

New research published in the journal Paleobiology suggest that the substantial incubation time required for sauropod embryos to develop and hatch may have been an important constraint, possibly explaining the small individual size sauropod eggs. It could also explain why the dinosaur hid these eggs in multiple clutches.

Using data from modern birds and reptiles, researchers from the University of Lincoln, UK, and George Mason University, Va. estimated that the time period between laying and hatching eggs - which were incubated in underground nests - was between 65 and 82 days.

This long incubation time increases the risk of predation, which coupled with the relatively low temperatures expected in the nest, may have been a significant factor in limiting the egg and clutch size.

Having larger eggs than are in the fossil record may have been advantageous because of larger hatchling size but this may have been outweighed by the increased risk of predation during the egg stage.

"We think that a long incubation period of sauropods is likely to have led to very high mortality through predation," Dr. Charles Deeming, from the UK's School of Life Sciences, said in a statement. "We suggest that the females laid their eggs in small clutches, possibly in different nesting sites, as an adaptive strategy to mitigate the high predation risk associated with long time of exposure in the egg stage."

The findings, though informative, may be a bit of a letdown for others.

"Some people might find it a bit disappointing that giant dinosaurs didn't lay equally giant eggs - but it's very satisfying to think that we might finally understand why," added Professor Ruxton, who was involved in the study.