Dinosaurs had a surprisingly rough-and-tumble love life, as evidenced by the fossilized remains they’ve left behind. Recent findings by leading paleontologists reveal that mating among certain dinosaur species was so intense it often resulted in broken bones, according to a new study published in the journal iScience.

The focus of this study is the Olorotitan, a species of duck-billed dinosaur. These creatures, which roamed the earth during the late Cretaceous period approximately 66 to 100 million years ago, were truly massive, reaching up to 26 feet in length and weighing about three tons. When researchers examined their fossilized remains, they consistently found a surprising number of broken bones and fractured spines, particularly in the vertebrae at the top of their tails.

Known for their powerful jaws and grinding teeth, these herbivores were widespread in their era. They also featured prominent crests on their heads, which scientists believe served as an attraction feature during courtship rituals. Initially, the frequent bone injuries were thought to result from fights or accidents within herds.

However, further evidence led researchers to a more intimate conclusion. The pattern of fractures suggested a connection to their mating practices rather than mere social interactions or environmental hazards. This discovery adds an intriguing layer to our understanding of dinosaur behavior, painting a picture of a complex and sometimes perilous prehistoric courtship.

At first, the scientists hypothesized the breaks were because the prehistoric beasts were sustaining injuries in fights or traveling in herds. But when new evidence came to light, they concluded the cracked skeletons shared a different — and kinkier — link, researchers uncovered.

In 2019, Filippo Bertozzo, a paleontologist from the Institute of Natural Sciences in Brussels ventured to Blagoveshchensk, Russia’s Paleontologic Museum to probe the dinosaur’s bones when he noticed the strange injuries, National Geographic Magazine reported.

“When I realized what I had in front of me, I had a cry of joy,” Bertozzo, the study’s lead author, told the outlet.

He had reportedly seen busted bones like these before in his research and in scientific literature — fractured vertebrate near the hadrosaur’s hips. And his rigorous research confirmed a theory scientists had already suspected — the cracks were caused by their brutal mating methods when one colossus monster mounted the other.

How dinos managed to mate had also been a difficult puzzle to solve because, “There aren’t other living animals with a hadrosaur-like tail, a large, long, muscular tail kept high and horizontal to the ground,” Bertozzo said. 

Dinosaurs had a single reproductive opening called a cloaca — an all-in-one hole used for digestion, waste elimination and reproduction — that’s only visible on the outside as a slit or opening under the base of the tail.

Today’s reptiles sport the same anatomical feature.

To mate, the lovers had to line up these openings perfectly, forcing close, hulking body contact. With massive tails held stiff and horizontal, they made dino love as the male transferred sperm to the female. But because of the massive weight and intense pressure involved, their lovemaking ended in severe bodily trauma to one or both participants.

Their bones mended naturally over time — until the next mating season. They lived only about 10 to 20 years, according to experts.

Although the actual mating was tough, the ancient behemoths did put on fairly complex, dramatic dances to impress and flirt with potential mates, according to National Geographic.

Scratches gouged into ancient rock reveal that dinosaurs gathered in courtship arenas, scraping the ground in ritual displays — the prehistoric equivalent of a dance floor, said the outlet.

The prehistoric hookups may have lasted only seconds — but millions of years later, the fossils are still telling scientists the story.