Happy played a starring role in welcoming visitors to the Museum’s Grand Opening events in December 2024.
Seventy years after its discovery, the Cleveland Museum of Natural History’s Haplocanthosaurus delfsi fossil, affectionately known as “Happy,” is ready to greet visitors arriving to experience the Museum’s full transformation.
And with its recent updates—remounted in a new exhibit with a new look—this septuagenarian dinosaur illustrates how even a fossil from the past can keep up with modern trends (in science, that is).
But how did Happy come to be such a Museum icon?
The tale began in the 1950s, when the Museum decided it needed to add a dinosaur to its collection to help teach the public about prehistoric life. After officially forming an expedition for the cause, the Museum sent a team to Utah in the summer of 1954 to see if they could strike gold—or rather, fossils.
Led by Yale University undergraduate Edwin Delfs and three high school students, the team at first didn’t have much success at finding a dinosaur. After all, the odds of discovering fossils are slim to begin with. As Delfs wrote in a January 1961 issue of The Explorer, “Of the billions of animals which have lived since the evolution of life on Earth, only a relative handful have been preserved in even a fragmentary manner.” However, it wasn’t long before the team received a tip about a possible dinosaur skeleton located in Colorado.
“Preparations were made, and one day in June of 1954 we climbed into our truck and headed west to find a dinosaur,” Delfs wrote. “It was thus that a giant Haplocanthosaurus, which in death had slumped into a wandering watercourse in Colorado, came to be exhibited in this Museum.”
After visiting the site in Colorado and finding signs of dinosaur bones, the team decided to start excavating that summer. It took three trips over the course of three years, but by 1957, the team had fully excavated the dinosaur—and it was on display in the Museum by 1961. Delfs and his team recognized the skeleton as part of the Haplocanthosaurus genus when they first discovered it, but the fossil was officially named Haplocanthosaurus delfsi in 1988 to honor Delfs’ contributions to the expedition.
Even though Happy died millions of years ago, we can still learn a lot about how it may have lived from the fossilized bones that remain. In life, Happy was more than 72 feet long from head to tail—that’s about as long as two telephone poles stacked on top of each other. Scientists think that the sauropod weighed about 25 tons, which is more than twice as much as a Tyrannosaurus rex. But even though Happy’s size probably looked pretty menacing, we know that Happy was primarily a plant-eater based on teeth from other members of the Haplocanthosaurus genus.
Thanks to other fossil evidence, we also know that the area Happy lived in probably had plenty of plants to eat. The site in Colorado where Happy was discovered is part of the Morrison Formation, where numerous dinosaur species have been uncovered—from Diplodocus to Allosaurus. Flowering plants had not evolved yet during the Jurassic period while Happy was alive, but the landscape likely had lots of shrubs and leaves for plant-eating dinosaurs to munch on.
The fossil hunting team’s lucky find remains one of the Museum's biggest discoveries to date. About half of the mounted skeleton is made of real fossilized bone, which is rare for dinosaur specimens of similar sizes. The other parts of the skeleton, including the skull, are modeled after similar specimens in the Haplocanthosaurus genus and other sauropods. Happy is also the holotype for the H. delfsi species, meaning that all other potential specimens are compared against Happy to determine if they share enough characteristics to belong to the same species.
When Happy was first mounted in the Museum in the 1960s, exhibit preparators originally positioned the fossil laying along the ground, as pictured above. Soon after, the sauropod was remounted in a standing position, but with the tail dragging along the floor. Today, however, scientists have gathered more evidence about sauropod anatomy and physiology. Using this scientific evidence, we now know that in life, Happy likely walked with its tail lifted off the ground to counterbalance its head.
Before installation in the new Visitor Hall, the Museum sent Happy to Research Casting International, a paleontological conservator in Ontario, Canada, where the dinosaur was remounted in a more scientifically accurate position—with both head and tail both lifted off the floor. And today, visitors can get up close and personal with one of our most iconic specimens right when they enter the Museum.
Happy’s legacy as a Museum icon can also be seen in our logo. Cleveland-based design firm Nottingham Spirk first developed the Museum logo featuring Happy’s silhouette in 1972, and it has since become one of the most recognizable logos in the city. And in the midst of our transformation, the Museum decided to redesign our logo to accurately reflect Happy’s new mount and updated tail placement. This new logo still keeps the originality of the design, but is now more scientifically accurate—just like the fossil itself.
With its updated mount and new home in the Visitor Hall, the Museum looks forward to sharing Happy’s story with the public for many more decades. And, as long as there are researchers looking for more dinosaurs, we might even know more about Happy by then—because, as Delfs wrote in 1961, “How does a paleontologist seek a dinosaur or any other fossilized remains? Simply by looking.”
Be sure to visit Happy’s exhibit in the Visitor Hall, which is always free to explore. And don’t miss the dinosaurs now on display in the Larry Sears and Sally Zlotnick Sears Dynamic Earth Wing and the Evolving Life Wing, two of the new galleries now open as part of the Museum’s spectacular transformation. Learn more and get your tickets today!
