Science 1

Dinosaurs were large lizards that roamed the planet millions of years ago and then, rather suddenly, went extinct. Tyrannosaurus Rex, a giant, meat-eating dinosaur, was among the last to go extinct. Two scientists speculate as to why.

Hypothesis 1

Dinosaur extinction was the result of a massive meteorite colliding with Earth. This meteorite would have created an enormous crater in Earth’s crust, displacing thousands of tons of dust and debris. These fine dust and debris particles would have remained suspended in the atmosphere for some time, essentially forming a layer impenetrable by the sun’s rays. This “blackout” would have lasted for several months, resulting in drastically decreased temperatures and the death of acres upon acres of forest. Although all dinosaurs would have been weakened by the cooler temperatures, the herbaceous dinosaurs would have been directly impacted and died off sooner. The carnivorous dinosaurs would have died off later, able to feed on the remaining herbaceous dinosaurs. As these herbaceous dinosaurs disappeared, however, so too would the carnivorous dinosaurs.

Hypothesis 2

Dinosaurs were cold-blooded animals, and their metabolisms fluctuated with changing environmental conditions. The mass dinosaur extinction was the result of a short-term heat-wave followed by an immediate Arctic cold front, leading to a prolonged Ice Age. These cold-blooded giants would not have been able to cope with such drastic climatic changes. During the heat wave, dinosaurs would have eaten less and slept more, needing less food to maintain their body temperatures. As a result, they would not have high energy reserves (food stored in the body as fat.) When the cold front approached suddenly, the dinosaurs’ body temperatures would have dropped, resulting in a slowing of heart rates and metabolisms. Because of the lack of energy reserves, the dinosaurs could not maintain a body temperature or metabolic rate necessary to sustain life. Herbaceous dinosaurs, naturally leaner, would have died first. The carnivorous dinosaurs would have fed on the carcasses of these animals, but would have perished soon after.