The sixth installment of the Jurassic Park franchise—yes, sixth!—features the return of some of the original 1993 blockbuster’s cast members, including Jeff Goldblum and Laura Dern. However, the film, out this week, also features an even bigger star—quite literally.
In Jurassic World Dominion, Alan Grant, played by Sam Neill, comes face to face with the Giganotosaurus, a brutish creature known in the film as “the Giga.” The fictional paleontologist breathlessly declares that the Giga is “the biggest carnivore the world has ever seen.”
As you might expect, a film in which terrible lizards now roam the Earth alongside humans is not exactly a documentary. But Grant isn’t wrong, per se, about Giganotosaurus’, well, gigantic-ness. However, the actual truth of Giganotosaurus’ size—and how it stacks up to its predatory peers—is a bit more complicated.
The first Giganotosaurus was discovered in 1993 when amateur fossil hunter Rubén Dario Carolini happened upon its skeleton in Patagonia, Argentina. Paleontologist Rodolfo Coria believed it was the largest dinosaur yet, at 41 feet in length (that’s about two Asian elephants standing in a line). A few years later, after discovering further Giganotosaurus fossils, Coria upped that estimate to 45–47 feet. In contrast, the largest Tyrannosaurus known to science (colloquially known as “Sue”) stands in the Field Museum at a little over 40 feet.
Taking those numbers at face value, Giganotosaurus is indeed the bigger of the two. But there’s a catch. We don’t have complete skeletons of either predator, and comparing two partial skeletons is no easy feat. Because skeletons sadly don’t come preserved as a perfect set of connected bones, paleontologists have to fill in the missing gaps with educated guesses. “It’s impossible to get a modern rendering of a dinosaur exactly ‘right,’ ” science writer Riley Black noted in a Slate piece in December. “Today, when you picture a dinosaur you’re relying part on evidence and part on imagination—even if you’re a strict book reader and museumgoer.” Basically, it’s hard to gather what a living, breathing dinosaur species’s exact measurements were based on a bunch of bones from a specimen or two.
What ends up happening is experts make different arguments for a creature’s size based on different bones. Coria and colleague Leonardo Salgado determined that the femur of the Giganotosaurus was 2 inches longer than Sue’s, which they put forth as evidence that Giganotosaurus is bigger. Since then, there has been constant discourse about whether or not that’s indeed true. In 2004, paleontologists noted that despite the larger femur, the Giganotosaurus’ tibia was 3 inches shorter than T. rex’s, indicating that Giganotosaurus had actually been smaller. In 2013, paleontologist Scott Hartman used skeletal reconstructions on a computer to further argue that T. rex reigned supreme.
Of course, this is all bigger than just a T. rex and Giganotosaurus. In 2005, paleontologists discovered a snout of a Spinosaurus (say that five times fast) and concluded the dinosaur would have been anywhere between 52 and 59 feet, a figure that was later downgraded by paleontologist Nizar Ibrahim and colleagues to 49 feet. Still, by that guess, Spinosaurus is the largest known carnivorous dinosaur (an epithet that is evident across the internet). Sorry, Alan Grant!
Given that new dinosaurs can always be dug up, the verdict is bound to shift again. Paleontologists have suggested that there may have been even larger carnivorous dinosaurs than Spinosaurus, such as Mapusaurus and Carcharodontosaurus. But for now, the cards seem to be stacked against the Giganotosaurus.
And at the end of the day, how big these ancient creatures are in comparison to one another is more of a fun debate than a deeply important scientific question. “All the paleontologists agree … that it is far more important to understand the animals’ evolutionary history and their ecological roles than to settle the size contest,” wrote R. Monastersky, who chronicled the original Giganotosaurus vs. T. rex discourse in Science News in 1997. Sounds like size doesn’t really matter that much after all.