By Fred Wierum from https://commons.wikimedia.org Velociraptor.png Licensing cc-sa
These beasts who are wildly known for their intelligence are definently the killers of the Cretaceous. They were featured in Jurassic Park as big scaly terrifying beasts, but they are actually 3 fot tall chickens. Though they may be small they make up all that size in intelligence being as smart if not smarter than humans. They hunted in packs and had feathers. Though they may seem not so threatening they had natural weapons, their claws. From their toe tapping claw on their foot to their mighty serated teeth this was on epic beast.
By Ovulator from https://commons.wikimedia.org Maiasaurus.jpg Licensing cc-sa
When you think of dinosaurs you might think of the mighty T-rex or a poison spitting Dilophosaurus, but what you might not think of is a herd of big cow like Hadrosaurs protecting their young. That is what a Maiasaura is. Or at least what we think they are. They are not considered very intelligent by the size of the inside of their skull. Their name means "Good Mother Lizard". Their have been many finds of their offspring and herds of them that had died. Many have been found in Montana.
With a name meaning Tyrant lizard what dinosaur is a more well known killer than the Tyrannosaurus Rex. As a full grown adult they could reaach up to 40 feet long. They most likely attacked solitary creatures. Only rarely would you see a T-rex taking on prey even close to its size. They were probably creatures that lived by them selves or their offsprings. Their arms were tiny, but were used to rip apart prey on the ground. One of the most famous fossils is of Sue the Mighty T-rex.