Four years ago, in 2009, dinosaurs suddenly appeared in the eastern section of the Brookfield Zoo. After that year’s Halloween they mysteriously vanished, never to be seen again … or would they be?

They’re ba-a-ack, as “Dinosaurs Alive!” returns to the zoo. Twenty-three life-size animatronic dinosaurs have again taken up residence, as of April 6, in the same easternmost section of the zoo, and will be moving, bellowing and shrieking right before your very eyes and ears. An additional dino, the Shantungosaurus, is located next to the Roosevelt Fountain. At 20 feet tall and 50 feet long, he is the ideal scenic photo op for families.

These are not the same dinosaurs you saw back in 2009, but are close relatives. On the way into the exhibit and along the winding trail, you will read, on signs, about their “social lives” on newspapers’ and magazines’ front pages. These headlines reveal the innermost secrets of the “Lifestyles of the Prehistoric.”

Meteor magazine screams “FOWL PLAY!” from the duck-billed Olorotitan, who is throwing a hissy fit that he was around long before any ducks, so why should he be called “duck-billed”? The Pangaea Examiner newspaper features the Amargasaurus declaring that “I didn’t know I was laying eggs!” (A likely story.)

Obviously, these famous dinosaurs are used to paparazzi taking their photos, so feel free to click away. But don’t get too close. They look like they could bite, especially the full-grown Tyrannosaurus Rex, who, at the end of the trail, will give you a friendly smile full of long sharp teeth. This King of the Dinosaurs will not get huffy unless you happen to mention that the Spinosaurus was much larger and more ferocious than him.

Two other old favorites of the dino world are also waiting to see you. The Stegosaurus and Triceratops have made their temporary homes here and will greet you loudly.

The trail dinosaurs are definitely the outdoorsy types, but an additional 10 feathered dinosaurs prefer to live under a roof, and have taken up residence in a tent to the south of the main herd. Seven of the animatronic dinos here are just as noisy, and are real showoffs. Long ago, their brilliant plumage may have been used for camouflage and/or courtship.

You will also see here a younger, feathered version of the trail’s T-Rex, who will lose his feathers as he grows up.

Be sure not to miss the Gigantoraptor, who was once known to be the largest feathered animal in the world. Just admire him, tell him he is the largest, has “moves like Jagger,” and move on quickly. By the way, it’s true about the dancing!

“The males put on these elaborate dance displays in order to attract the females, much like modern day birds do when they want to attract females,” said Andre Copeland, interpretive programs manager for the Chicago Zoological Society.

Cover your heads when you come to the two Microraptors poised to take flight! The Sinosauropteryx is fearfully feathery, and looks like a giant reptile-chicken with extremely long and sharp claws. Don’t attempt to shake hands. Even if he had any.

There are also skeletal remains of two dinosaurs here, as well as a “Dino Dig” area for children to uncover fossils. The latter is most popular, although the kids don’t get to keep the fossils they dig up.

This year’s exhibition is markedly different from the one in the past.

“People are going to experience some of the new scientific discoveries made since then,” said Copeland. “Ten, 15, 20 years ago, we thought we knew it all. For example, people are going to see what scientists call the ‘Father of Modern Day Birds’, the Confusasaurus.

“DNA testing has been done on this bird to prove it has a genetic link to our modern day birds. People can come out and see what might have been the father of our modern day hawks and falcons,” he added. “And other scientific discoveries are being made every year.”

The return of “Dinosaurs Alive runs through Oct. 27. A separate entrance fee — $5 for adults, and $3 for children over 3 years old and seniors over 65 — is required. Zoo members receive half off.

For further information, visit the website.