Is it possible to bring dinosaurs back to life using fossilized embryos?

In 2010, when paleontologists unearthed a group of Jurassic dinosaur embryos in China, two things likely happened simultaneously: Steven Spielberg likely secured the film rights, and the team behind "Maury" probably planned a "Who's the Baby Daddy" episode featuring the fossilized remains.

However, scientists celebrated for a far more straightforward reason: the chance to understand how such massive creatures developed from such tiny beginnings.

Surprisingly, we know very little about this topic, as paleontologist Jack Horner highlighted in his 2011 TED talk. By studying the microscopic structures of various bones, Horner discovered that some dinosaurs followed the same bone growth patterns as their bird descendants. For instance, just as a cassowary doesn’t develop its distinctive bone ridge until later in life, certain dinosaurs retained youthful traits well into adulthood. This revelation showed that paleontologists had misinterpreted the bones: five supposedly unique Cretaceous species were actually younger forms of known dinosaurs [source: Horner].

Clearly, additional information is required, and the 2010 discovery of a Lufengosaurus colony's nesting site (along with the related 2013 paper published in Nature) provided the treasure trove scientists had been seeking. The site yielded 200 bones from the offspring of this long-necked herbivore, along with bone fragments and eggshells, representing multiple nests and at least 20 embryos in various developmental stages. Dating back 190 to 197 million years, these are the oldest dinosaur embryos ever discovered [sources: Reisz et al.; Than].

This discovery kept paleontologists and dinosaur enthusiasts captivated for weeks, but there was more. Almost as an afterthought, scientists revealed that they had detected "organic residues, likely direct products of the breakdown of complex proteins" among the bones [source: Reisz et al.]. This quickly led to the inevitable question: Can we finally bring dinosaurs back to life?

While the question isn't as far-fetched as it once seemed, the answer remains no. Despite remarkable advancements in genetics and genomics, practical challenges in obtaining and cloning dino DNA likely render "Jurassic Park" an impossibility. Additionally, ethical concerns and potential unintended consequences make us question whether attempting such a feat is even advisable.

Egged on by Advances

In the 1994 movie "Dumb and Dumber," Mary Swanson tells Lloyd Christmas that their chances of being together are "one out of a million," to which he responds, "So you're telling me there's a chance."

Paleontologists often find themselves in Mary's shoes when addressing questions about reviving dinosaurs. They also likely ponder how so many viewers of "Jurassic Park" and its sequels overlooked the recurring theme of unintended consequences.

Does the discovery of dinosaur embryos pave the way for reptilian resurrection? Unfortunately, no. Dinosaur eggs are tens to hundreds of millions of years past their expiration date and have fossilized, making them far from ideal for incubation. As for the embryos, they are merely skeletal remains, offering little assistance in this endeavor.

What about the organic material—have we finally uncovered dinosaur DNA? Not quite. The paleontological community has debated potential organic tissue discoveries for years, but DNA remains elusive (and likely always will—see sidebar).

Consider the Tyrannosaurus rex, for instance. In 2005, scientists used weak acid to demineralize Tyrannosaurus bone, extracting soft, flexible "tissues" from the remains, including structures resembling bone cells, red blood cells, and blood vessels. Subsequent discoveries yielded more preserved tissue samples from various species and time periods, indicating this was no isolated incident [sources: Kaye et al.; Schweitzer et al.; Schweitzer et al.].

Unsurprisingly, this caused quite a stir. In the meticulous field of paleontology, such a find was akin to a touchdown, but further scrutiny through carbon dating and scanning electron microscopy revealed the truth. The stringy structures and hollows were not dinosaur tissues but bacterial biofilms—clusters of bacteria held together by polysaccharides, proteins, and/or DNA. While they may resemble dinosaur cells, they are more comparable to tooth plaque [sources: Bayles; Kaye et al.].

Regardless of their nature, these discoveries left paleontologists questioning: Could genuine dinosaur DNA still be out there, waiting to be found? They refined their methods and, with the Lufengosaurus nest, hit the jackpot. Exciting? Absolutely. Organic? Certainly. DNA? Not even close [source: Reisz et al.].

But what if it had been?

Not All It's Cracked Up to Be

Over the last decade, breakthroughs in stem cells, ancient DNA recovery, and genome reconstruction have brought the idea of "de-extinction"—especially for species closely related to those still alive—closer to reality [sources: Kolata; Zimmer]. However, how close we are and what this means for far more ancient creatures remains uncertain.

In 2003, scientists achieved a breakthrough by cloning an extinct Pyrenean ibex, also known as a bucardo (Capra pyrenaica pyrenaica), using frozen cells. However, the cloned animal survived only minutes after birth [sources: Kolata; Mabry; Zimmer]. Similarly, Australian researchers have been working to revive the Southern gastric brooding frog (Rheobatrachus silus), which vanished decades ago, but their efforts have yet to progress beyond the early embryonic stage [source: Kolata].

Despite these initial setbacks, these efforts have sparked hope for more ambitious resurrections, such as woolly mammoths, passenger pigeons, and a Yukon horse extinct for roughly 70,000 years. While this seems like an eternity, it’s merely one-tenth of 1 percent of the time since the last dinosaurs roamed the Earth [source: Kolata].

Even if dinosaur DNA were as fresh as yesterday’s yogurt, numerous ethical and practical concerns would give pause to all but the most reckless scientists. Questions arise: How would such a process be regulated? Who would oversee it, and under what conditions? How might de-extinction impact the Endangered Species Act? What about the suffering caused by failed attempts? Could we inadvertently revive extinct diseases or create invasive species on an unprecedented scale [sources: Kolata; Mabry]?

There are potential benefits, of course. Similar to the reintroduction of wolves to Yellowstone National Park, reversing recent extinctions could help restore balance to damaged ecosystems. Some argue that humanity has a moral obligation to revive species it has driven to extinction [sources: Kolata; Mabry; Zimmer].

For now, the lack of viable DNA makes the debate largely theoretical. While it’s possible that a more recent creature, like a frozen woolly mammoth, might yield an intact (albeit freezer-damaged) cell, dinosaurs remain out of reach. The degraded proteins from Lufengosaurus might be the closest we ever get to a real-life "Jurassic Park" [source: Kolata].

Another approach involves "back-breeding," where scientists attempt to revive an ancestral species by selectively breeding descendants that retain distinctive genetic traits from it. Since 1945, some German breeders have claimed success in recreating the aurochs (Bos primigenius), an extinct wild ox and ancestor of modern cattle, though the scientific community remains skeptical [sources: Encyclopaedia Britannica; Kolata].