Crocodiles in Mesa? Crikey! Mother Nature’s perfect predator is the star of "When Crocodiles Ruled," an exhibit opening Saturday at the Mesa Southwest Museum.
"It’s a super neat exhibit," says Robert McCord, the museum’s chief curator of natural history. "It tries to have something for everyone."
The exhibit, which is on loan from the Science Museum of Minnesota through Dec. 31, takes visitors back 60 million years to the early Cenozoic Era. The dinosaurs were gone, possibly the victims of an asteroid impact 7 million years earlier, and the Earth’s tropical ecosystems were changing. The crocodile stepped out of the dinosaur’s shadow to occupy the top spot on the food chain.
"I think crocodiles are fantastic," says Geoff Hall, vice president of living collections at the Phoenix Zoo. "People love this animal because they’re prehistoric. They outlived the dinosaurs, and that is an attraction."
Crocodiles were designed right the first time, says Hall: Their bodies were suited to living in tropical regions.
Crocodiles normally dive for only a few minutes at time, but they can hold their breath underwater for up to two hours. They have a fourchambered heart and an ectothermic metabolism, which means they can go for a long time without eating. When they do decide to eat, they will devour up to half their body weight in one meal.
Their speed — some crocodiles can run up to 40 mph —stealth and leverlike jaws make them ferocious and effective predators.
"Have you ever seen a Nile crocodile taking a wildebeest down?" says Hall. "They’re just awesome."
The exhibit is based on fossils found in the Wannagan Creek quarry in North Dakota. Scientists from the Science Museum of Minnesota have been excavating and studying the site for more than two decades. When visitors walk through the exhibit, they will see life-size depictions of what life was like in North Dakota 60 million years ago, which McCord says "sure as heck is not the same as it is today."
The region was a subtropical swamp populated by crocodiles and other crocodilians such as alligators and the extinct champosaurus. Changes in the world’s climate and the evolution of other plants and animals is the subject of the exhibit’s second part, "World Change Central."
"Greenland was covered with crocodiles, there were palm trees in Alaska and a cypress forest in North Dakota," says McCord. "Things have changed a lot since then. Making (visitors) ponder how the Earth has changed is an important subgoal."
The third part of the exhibit is a field camp based on the site at Wannagan Creek. Visitors will learn about how paleontologists work, have a chance to assemble a champosaurus and sift sand for fossils.