In eggs

As in, a fertile dinosaur egg, not the adult. Moving livestock is always tricky, even more so when said livestock is composed of strong and dangerous creatures, which have a tendency to die easily in the wrong temperature, thanks to the fact that their cold-blooded.

If pirates wanted to smuggle these creatures from their distant territories back to these lands, they'd kill the parents and steal the eggs (or just steal the eggs and run like crazy), then ferry the eggs back, and sell them for a tidy profit. Of course, you'd have to prove that it's a bona fide dino egg, so perhaps the pirates would let them hatch into baby dinos on the far side of the ocean, but the easiest way to smuggle a massive T-rex is to just steal a T-rex egg and take it across the ocean like that.

In eggs

As in, a fertile dinosaur egg, not the adult. Moving livestock is always tricky, even more so when said livestock is composed of strong and dangerous creatures, which have a tendency to die easily in the wrong temperature, thanks to the fact that they're cold-blooded.

If pirates wanted to smuggle these creatures from their distant territories back to these lands, they'd kill the parents and steal the eggs (or just steal the eggs and run like crazy), then ferry the eggs back, and sell them for a tidy profit. Of course, you'd have to prove that it's a bona fide dino egg, so perhaps the pirates would let them hatch into baby dinos on the far side of the ocean, but the easiest way to smuggle a massive T-rex is to just steal a T-rex egg and take it across the ocean like that.