This year marks the 35th anniversary of a discovery that redefined our understanding of the Tyrannosaurus Rex and captivated the world. It’s a story of serendipity, fierce legal battles, groundbreaking science, and an unexpected journey into pop culture. Discovered in South Dakota in 1990 by fossil hunter Sue Hendrickson, Sue is not just any dinosaur skeleton; it is the largest and most complete T-Rex fossil ever found, with over 90% of its bones recovered. Today, Sue stands proudly on display at the Field Museum in Chicago, demonstrating to visitors its enduring legacy. Sue is certainly not an ordinary dino, because its excellent completeness allowed for revolutionary scientific understandings, its acquisition sparked an unprecedented legal and financial drama, and its subsequent public persona transformed it into a beloved cultural icon, far beyond a typical fossil. Although the biological sex of Sue has not been determined, the exceptional completeness and exquisite preservation truly distinguish this fossil, and because its sex is unknown, I will be referring to Sue as “it” instead of he or she.
The serendipitous find: A fossil hunter’s unforgettable day
The extraordinary journey of Sue began on August 12, 1990, under circumstances that highlight the role of chance in scientific breakthroughs. While her team was occupied with fixing a flat tire, fossil hunter Sue Hendrickson embarked on a solo exploration across the plains of western South Dakota. After hours of hiking, she reached a 60-foot-high bluff. It was there, about 8 feet above the ground, that she spotted three massive bones protruding from the rock face. This solitary observation, made during what might have been considered downtime, would lead to one of the most significant palaeontological finds in history.
Hendrickson immediately recognised the potential significance of her find and reported it to Peter L. Larson, president of The Black Hills Institute of Geological Research, her employer. A six-member team then embarked on a 17-day excavation process to extract all the bones from the site. It was only upon completion of this work that they fully grasped the magnitude of their discovery: they had uncovered the most complete Tyrannosaurus Rex skeleton to date, with an astonishing 90% of its bones recovered. The skeleton was subsequently named “Sue” in honor of its discoverer, which cemented her place in palaeontological history. This narrative demonstrates how major scientific discoveries are not always the result of direct, methodical pursuit but can often arise from unexpected moments and individual initiative, emphasising the importance of keen observation and preparedness in the field.
A life etched in bone: Sue’s scientific story
Sue’s exceptional completeness and exquisite preservation truly distinguish this fossil. With 90% of its bone volume recovered, including 250 of the approximately 380 known bones, Sue stands as the most complete adult T-Rex ever found! This remarkable preservation extends to rare elements such as the furcula (wishbone), stapes (ear bone), and almost all the gastralia (belly ribs). The fossilized bones exhibit an extraordinary level of surface and histological (tissue) detail, revealing where muscles, tendons, and ligaments were attached, and even retaining intact cellular structures within the bone.
This unparalleled completeness is not merely a quantitative fact, but represents a qualitative leap in palaeontological study. Before Sue’s discovery, understanding T-Rex anatomy often relied on piecing together fragments from multiple individuals, leading to composite interpretations. Sue’s holistic nature, however, provided paleontologists with an accurate, proportional understanding of a single T-Rex, revolutionising the field’s grasp of this iconic predator’s biology. This shift allowed for a more precise reconstruction of T-Rex anatomy, moving beyond speculative composites to a detailed, individual portrait.
Analysis of Sue’s bone growth rings revealed an “extreme teenage growth spurt”, during which the dinosaur likely gained 35-45 pounds per week until reaching adult size by age 20. This rapid growth pattern offers crucial information about T-Rex metabolism and developmental biology. Studies of these rings also indicate that Sue lived to be an estimated 28-33 years old. This makes it one of the oldest T-Rexes ever found!
Sue’s skeleton bears evidence of several debilitating ailments, including healed broken ribs, a torn tendon, and a damaged shoulder blade, likely sustained from struggling prey. The presence of arthritis in its tail further indicates the challenges of its advanced age. Perhaps most striking is a severe bone infection in its left fibula, which grew to twice the size of the right, possibly from an encounter with a horned or armored dinosaur.
A parasitic infection of Trichomonas gallinae in the jaw could have caused swelling and potentially led to death by starvation due to difficulty eating. The presence of such extensive injuries and diseases, particularly the debilitating parasitic infection that would have made eating difficult for an 8-ton animal requiring massive caloric intake, leads to an intriguing inference: an animal in such pain would likely require support. This strongly suggests that T-Rexes might have been social animals that cared for their injured, and this challenges the long-held image of them as purely solitary, aggressive hunters. This shifts the scientific narrative from a purely biological description to one that includes behavioral and ecological complexity, offering a more nuanced understanding of their lives.
The ability to determine Sue’s age from bone rings and combine this with the extensive pathologies allows for a unique life history reconstruction. Sue’s skeleton provides a rare, almost biographical account of a dinosaur’s life, rather than just species-level data. This enables scientists to study variation, the impact of environmental stressors over a lifetime, and the progression of diseases in a prehistoric animal.
The battle for the bones: A legal drama
The story of Sue took an unexpected turn from scientific marvel to legal battleground. After its excavation, the Black Hills Institute of Geological Research, which had paid $5,000 to the landowner, Maurice Williams, for excavation rights, moved the fossil to Hill City, South Dakota. However, the land where Sue was found was held in trust by the U.S. government for Williams, who was a member of the Cheyenne River Sioux Tribe. In May 1992, federal officers seized the fossil, alleging a violation of the Antiquities Act, which prohibits the removal of antiquities from federal land and carries a penalty of up to 90 days in jail and a $500 fine.
This initiated a complex, five-year legal dispute involving Maurice Williams, the Black Hills Institute, the federal government, and the Cheyenne River Sioux Tribe. The Institute argued that the fossil was being irreparably damaged in government storage due to a lack of expertise. The court noted the government’s seizure of a “priceless, archaeological treasure” for a minor criminal charge, highlighting the disproportionate response. The legal battle raised fundamental questions about land ownership, tribal sovereignty, and the rights to palaeontological discoveries on tribal lands. The fact that the land was held in trust for a member of the Cheyenne River Sioux Tribe and that the legal proceedings questioned federal jurisdiction over the tribe and tribal sovereign immunity shows the complexities of merging federal law, private property rights, and Indigenous sovereignty in the context of scientific discovery.
This aspect of Sue’s story embeds its discovery within a significant socio-political and legal narrative that transcends pure palaeontology, bringing to the forefront historical injustices of land ownership and the ongoing struggle for self-determination for Indigenous Peoples.
The culmination of this legal saga was an unprecedented event in the world of palaeontology. In October 1997, Sue was put up for public auction at Sotheby’s in New York City. The bidding, which lasted only nine minutes, started at $500,000 and escalated rapidly. The Field Museum in Chicago acquired Sue for $8.36 million. This was the most money ever paid for a fossil at auction! This dramatic legal and financial saga also highlights a broader issue for palaeontology and natural history: the increasing commercialisation of significant scientific discoveries. While it ultimately brought Sue to a public museum, it also set a precedent for high-stakes bidding which could limit access for research institutions without vast corporate backing. This raises ethical questions about whether invaluable scientific heritage should be subject to market forces in the first place, and how such discoveries can be equitably managed for public benefit and scientific advancement.
Sue’s grand home:
After its record-breaking purchase, Sue embarked on a new journey of meticulous preparation and mounting at the Field Museum. A dedicated team of 12 museum preparators spent over 30,000 hours cleaning and repairing the skeleton, with an additional 20,000 hours invested in building the exhibit itself. The museum’s publicly viewable McDonald’s Fossil Preparation Lab showcases the various techniques employed in this painstaking process. These include mechanical preparation using pneumatic tools like jack-hammers and sand-blasters, manual preparation with hand tools and dental instruments, and chemical preparation involving acid baths to dissolve the surrounding matrix, all often performed under a microscope to prevent damage to the delicate fossil. Beyond these primary methods, the work also encompasses repairing, reconstructing, molding, casting, and meticulous record-keeping, ensuring the fossil’s integrity and accessibility for future study.
Sue made its dramatic public debut in Stanley Field Hall on 17 May, 2000. The Field Museum’s exhibition, “SUE: The T. rex Experience,” is designed to be multi-sensory and immersive, aiming to transport visitors directly into the Late Cretaceous period. Visitors can “take a whiff of their putrid breath, watch SUE tromp through the Late Cretaceous forest, feel the texture of dinosaur skin, and hear the subsonic rumble of a T. rex”. The exhibit features a fully articulated cast skeleton, full-scale replications, touchable models, digital interactives, and large media elements, altogether bringing Sue’s ancient world vividly to life. The original skull, too heavy for the mounted skeleton, is displayed separately on the second floor, which allows for closer examination of its unique pathologies. This immersive and transparent approach to exhibition represents a significant evolution in how natural history museums engage the public. It moves beyond traditional static displays of bones to create an interactive experience that fosters a deeper public connection and understanding of science. The publicly accessible preparation labs further demystify the scientific process, inviting visitors to witness the painstaking work involved in bringing such ancient wonders to light.
Beyond the Museum:
Beyond its scientific and exhibition prominence, Sue has achieved an unexpected level of cultural resonance. The fossil has garnered cult status as a witty, irreverent personality on social media. This unexpected digital persona has transformed a prehistoric fossil into a contemporary social media voice, engaging a vast and diverse online audience with humor and unique perspectives. This cultural phenomenon demonstrates the power of modern media to democratise scientific knowledge and engage new audiences. By adopting a relatable and humorous persona, Sue has broken down traditional barriers between scientific institutions and the public, making paleontology accessible and exciting to a broader demographic.
Notably, Sue is “lauded as a non-binary icon by followers of the account”. The Field Museum itself acknowledges the unknown biological sex of the actual animal and, in public communications, refers to the specimen as “Sue” instead of using gendered pronouns like “she” or “he”. This deliberate choice, combined with the online persona, has resonated deeply with a diverse audience, particularly within LGBTQIA+ communities. The embrace of Sue as a non-binary icon showcases how scientific figures, even fossilized ones, can become symbols for contemporary social movements, challenging conventional gender norms and promoting inclusivity in unexpected ways. This makes Sue a unique bridge between ancient history and modern identity discussions, truly setting it apart from other dinosaur discoveries.
Final reflections:
Sue is undeniably extraordinary due to a confluence of factors that extend far beyond its impressive size. Its unparalleled 90% completeness unlocked revolutionary understandings into T-Rex biology and behavior, allowing scientists to piece together a detailed “life history” of an individual predator, rather than relying on fragmented composites. The extensive pathologies observed in its bones, from healed injuries to parasitic infections, not only paint a picture of a challenging existence but also suggest the potential for complex social behaviors, such as caregiving within T-Rex communities.
The saga of Sue’s acquisition, marked by a dramatic legal battle over ownership and a record-breaking auction price, highlighted the intersection of science, law, and Indigenous rights. This unprecedented event brought to the forefront discussions about the commercialization of scientific heritage and the equitable management of discoveries on lands with complex historical claims. Furthermore, the astounding preparation and immersive exhibition at the Field Museum transformed public engagement with paleontology, moving beyond static displays to create a dynamic, multi-sensory educational experience.
