Baby T. rex bones found stashed in museum drawer: ‘Vanishingly rare’

It’s a tyke-rannosaur.

The T-rex might have grown into the biggest, most terrifying creature to ever roam the planet, but it started life no bigger than a house cat.

British researchers claim they’ve identified the first-known fossils of baby tyrannosaurs, offering a rare glimpse at the earliest days of the giant reptile’s life, according to a groundbreaking new study in the journal Biology.

“Going through museum collections, my colleagues and I have discovered the first remains of hatchling tyrannosaurs,” declared Nick Longrich, a paleontologist and evolutionary biologist at the University of Bath in the UK.

Longrich and his team found the “vanishingly rare” remains while looking for smaller fossils, which they thought were getting short shrift compared to the fossils of prehistoric megafauna, per Science Alert.

But during their hunt for the small stuff, the scientists ended up finding the bones of one of the largest predators to ever walk the Earth.

The team initially mistook one of the samples for the foot bone of an adult theropod dinosaur. However, they later determined that it belonged to a baby rex based on its porousness, which was caused by the dense network of blood vessels nourishing the bone as it grows.

“This is typical of an immature dinosaur,” said Longrich, who confirmed it was a T. Rex foot bone by comparing it to other fossils from the epoch.

At first, researchers thought the fossil was a “tiny” adult specimen — the bones were almost a dead ringer for the grownups — but realized it was a dinosaur junior after closely examining other bone and foot fossils.

Ultimately, they realized that the tyrannosaur tykes were fairly runty, measuring just 30 inches long and weighing around 5.5 pounds. That’s the average size of a Yorkshire terrier.

They were likely only around 4 pounds when newly hatched — a lot smaller than prior projections that claimed they measured three-feet across from nose to tail.

This was also a far cry from “Jurassic Park,” movies, in which these toothy tot’s proportions seemed on par with those of an even more deadly adult velociraptor.

While a complete T-rex egg has never been identified, scientists determined from these remains that they were similarly small, and laid in large clutches of 20-30, similar to some species of turtle.

From this, the researchers surmised that the Cretaceous carnivores’ reproductive strategy was to spew out large bundles of offspring that they provided relatively little care for, rather than investing more energy in fewer babies, as previously believed.

While this cheaper-by-the-dozen MO might seem cold, Longrich noted in the clip that T-rex parents invested “more in their offspring that crocodilians, turtles and lizards,” even if they were less attentive than “modern birds and mammals.”

In fact, he theorized that T. Rex’s rearing style marked an evolutionary transition between the two reproductive styles.

“Avian [and] mammal intensive parental investment and care seems to evolve gradually in the Mesozoic,” said Longrich. “At the same time [that] tyrannosaurs are evolving to care for larger and fewer young (relative to reptiles), we see mammals and plesiosaurs — even insects — making similar shifts. Parental investment strategies change a lot in the Jurassic and Cretaceous periods.”

Just imagine their teething phases.