Going toe to toe with the big boys.

• Position: World of Science

"The World's Largest Dinosaurs" is divided into multiple content sections:

Introduction. Visitors immediately will encounter the enormous head of an Argentinosaurus, considered the world's largest sauropod. Discovered in Argentina, it probably weighed up to 90 tons and measured up to 140 feet long.

Size. This section explores the biological effects of size in animals both huge and tiny, living and extinct. To provide perspective, a 15-foot-tall replica of a Supersaurus hind leg is displayed among models, specimens, and bones of living animals such as a hummingbird, dwarf gecko, an African elephant, and human. It is here museumgoers will meet Mamenchisaurus. Standing 11 feet tall at the shoulders and measuring 60 feet long--approximately the size of a tractor-trailer--the centerpiece of this exhibition is a life-sized, fleshed-out model of an 18-year-old female. Though not the largest sauropod, Mamenchisaurus is known for its remarkable 30-foot-long neck, which accounts for fully half of its body size. Textured skin on one side of the model gives a sense of this enormous animal's appearance; on the other side, the creature appears to be dissected, with key organs, including the heart and lunge, isolated and modeled at life size. A video projected on the animal's midsection details how a Mamenchisaurus' respiratory, circulatory, and digestive systems contributed to its enormous size.

Eat. Sauropods developed into hugely efficient eating machines by employing "fermentation tank" digestive systems, herbivorous diets, incisor-like teeth, and by swallowing vegetation whole.

React. Sauropods had small brains in their relatively small heads. An Apatosaurus brain weighed, at most, four ounces compared to a 48-ounce human brain. Brain size is explored, while the "booster brain" myth, which hypothesized that some sauropods possessed a second "brain" in their tail bone, is debunked. On display is half of a Diplodocus braincase, which provides scientists a number of important clues about the large-scale brain structure of this extinct dinosaur.

Reach. With their crane-like necks, sauropods were able to reach food that other plant eaters could not. The biomechanics and adaptive advantages of a long--but surprisingly lightweight--neck are revealed. The intricate structure of sauropod vertebrae is illustrated by a huge fossil neck bone; also explored is the effectiveness of long necks as cooling systems.

Babies. Emerging from an egg the size of a...