Were Fossil Dinosaur Eggs Laid Normally?

"Eggs were everywhere. As we strode across the mud-cracked flats exposed beneath the banded ridges of crimson rock that radiated under the searing Patagonian sun, crew members began kneeling down to examine small, dark gray fragments of rounded rock with a curious texture. We knew immediately from the distinctive texture that we had found something startling--dinosaur eggs." -- Luis Chiappe and Lowell Dingus writing in "Walking On Eggs" (2001)

"Dinosaur eggshells, whole eggs, clutches of eggs, and even baby dinosaur bones have proven to be more common than was previously realized... It is clear that dinosaur eggs and baby bones have been found on almost every continent except Antarctica. I suspect that they will eventually be found there as well." - Kenneth Carpenter, writing in the book "Eggs, Nests, and Baby Dinosaurs (1999)

Notice one word that is not used... "nests." The word "clutch" simply refers to a group of eggs, not a nest.

Millions of dinosaur eggs have been found, along with huge numbers of broken eggs (eggshell). In one area in Spain, for example, it is estimated that there are 300,000 eggs. This abundance of physical evidence should have resulted in a question being asked. An important question: Were dinosaur eggs laid normally? The evolutionary assumption is yes, so the question is never asked. But a review of the evidence makes it clear this is a question that needs to be asked and answered.

Let's Start By Learning About Dinosaur Eggs

Let's say you wanted to own a dinosaur egg. You go to EBay and notice there are several for sale. You pick what looks like a good one, and a few days later you have a dinosaur egg... that is most likely a fake from China. What do you need to know about real dinosaur eggs?

Dinosaur eggs have two basic shapes. There are the round ones that were laid by dinosaurs such as sauropods and ornithpods, and there are elongated eggs laid by dinosaurs such as theropods. As mentioned in the quote above, dinosaur eggs have a texture. They are not smooth like chicken eggs. The above image shows a replica theropod egg that we have in our museum. You can clearly see the texture.

The specific type of dinosaur that laid the egg cannot be identified, because it is rare to find dinosaur eggs with embryos inside. It is also extremely rare to find fossil bones near dinosaur eggs. Eggs are found out in the open on flat sediment surfaces with little or no evidence of vegetation. And there is little fossil evidence (make that essentially none) that the dinosaur that laid the eggs stayed with their eggs.

In addition, not all eggs are in clutches. Some are, but individual eggs are found scattered around between clutches. Chiappe and Dingus write about the eggs they found in Patagonia:

"Other dinosaurs laid their eggs in a spiral pattern within a nest*. Still others laid their eggs in rather poorly defined patterns within a nest*, and some laid them randomly across an area without a nest." (Walking On Eggs, page 87)

The term "nest" is used three times in that quote. Paleontologists often refer to clutches of eggs, with no nest structure, as a "nest" even though there is no evidence of an actual nest. They are assuming there must be a nest. But that's not what is observed.

Dinosaur eggs are often found in localized areas in which clutches are close together, often in multiple sediment layers, with some individual eggs scattered about. In just a couple of instances have there been reports in which evidence (a change in sediment color) for a nest structure has been inferred.

How Were Dinosaur Eggs Preserved and Fossilized?

The question of dinosaur egg preservation and fossilization is similar to that for dinosaur footprints. Eggs must be quickly and deeply buried, in this case to protect them from predators. But, the flow of water carrying the sediment must be gentle so as not to break or move the eggs. Let's think about this. To get enough sediment to quickly and deeply bury (two or three feet of sediment) eggs requires an energetic water flow that can erode rock quickly. That means a flash flood type of flow. That's what it takes today to produce a lot of sediment. But, an energetic flash flood will move and break the eggs. So that's not an option. We don't see any mechanism operating today that could accomplish this.

Here is another interesting piece of evidence: Some dinosaur eggs have been found in marine strata. Carpenter writes:

"One of the oddest occurrences of an egg is from the Mooreville Chalk of Alabama. This chalk was deposited in the northern end of the proto-Gulf of Mexico. How this egg came to rest on the bottom of the sea is unknown." (Eggs, Nests, and Baby Dinosaurs, page 19).

Other eggs have been found in sediment containing marine fossils (as are many bone fossils), but chalk forms underwater. Dinosaur don't lay eggs underwater, and eggs are too fragile to have been carried there by a flood. Maybe they were carried in floating vegetation? Seems far-fetched.

Don't Stop Until You Have The Complete Story

Pathological Eggs: The formation of an egg is a complicated process that takes place within the dinosaur. The last step is putting the hard shell on the egg. Then it is stored in the mother's body until all of the eggs can be laid. If the mother is under stress and is prevented from laying the eggs, some of the eggs may have pathologies, meaning they are not normal. A common pathology is multiple shells. If the egg is unable to be moved into the storage area in the lower uterus, and moves back up into the shell making area of the uterus, a second shell will form. Only the most recent eggs to form within the mother would have this pathology. When dinosaur eggs are examined using an electron microscope these multiple shells can sometimes be detected. In one example 10% of fossil dinosaur eggs were found to have multiple shells. That is far in excess of what is common under normal conditions.

"Abnormal, multilayer eggshells are frequently reported in fossil specimens. Excavation of one clutch exposed 30 eggs, distributed in three levels, including 27 normal eggs and 3 multilayer eggs. The three abnormal eggs occupied the highest level within the clutch and represent the last eggs laid by the female sauropod." - Jackson et.al., "Abnormal, Multilayered Titanosaur Eggs From Insitu Clutches At The Auca Mahuevo Locality, Neuquen Province, Argentina" (2004)

"This abnormal condition often results from physiologic or environmental “stress” and prolonged egg retention by the female. A similar condition found in fossil dinosaur eggshell from France was purported to result from environmental stress associated with the Cretaceous extinction event." - Jackson, Schweitzer and Schmitt, "Dinosaur Eggshell Study Using Scanning Electron Microscopy" (20020

Many Eggs Have Not Hatched: We can't help notice that the dinosaur clutch replicas in our museum, as well as the clutches we've seen in other museums, nearly all have unhatched eggs. Kenneth Carpenter writes:

"A surprising number of whole dinosaur eggs are known, especially the big, spherical Megaloolithus eggs from France, India and Argentina. Why these eggs failed to hatch is a subject of much speculation." (Eggs, Nests and Baby Dinosaurs page 119)

The conclusion that makes sense is that they were buried before they could hatch.

There is possible evidence for hatched eggs in that some fossil dinosaur eggs are broken on top, with no egg shell fragments found inside. It is assumed this indicates that the shell was broken from the inside. Is this a valid assumption? I just ran a simple experiment. I cracked open the top of a chicken egg and sucked out the contents. No shell fragments were left inside. So broken tops could be a sign of predators. Also, Oard reports that, "Many of the broken top eggs have shells within the egg." (Dinosaur Challenges and Mysteries, page 105). This would indicate the tops of the eggs were broken by something other than hatching, such as sediment compaction or a predator.

Traces of Protein Found In Dinosaur Eggs Schweitzer, et.al in a paper titled "Molecular Preservation in Late Cretaceous Sauropod Dinosaur Eggshells" reported detecting protein in dinosaur egg shells. This is very interesting because proteins degrade rapidly and certainly do not last millions of years. It's an indication fossil dinosaur eggs are not all that old.

Next - Eggs, Evaluate The Evidence