Source: National Marine Fisheries Services' Northeast Fisheries Science CenterHow many kinds of lobsters are there in the United States? Two kinds of lobster-like crustaceans exist in U.S. waters…
Source: National Marine Fisheries Services' Northeast Fisheries Science CenterWhat is the difference between soft and hard shell crabs? They are the same species. A soft-shell crab is one that has…
—Ronald J. Litwin, Robert E. Weems, and Thomas R. Holtz, Jr.
Source: United States Geological Survey When did the dinosaurs first appear on Earth? Are all fossil animals dinosaurs?…
The oldest dinosaur types are known from rocks in Argentina and Brazil and are about 230 million years old. The most primitive of these types, Eoraptor, was a small meat-eating dinosaur. Because…
Dinosaurs generally are named after a characteristic body feature, after the place where they were found, or after a person involved in the discovery. Usually the name consists of two Greek or…
The largest complete dinosaur we know of was Brachiosaurus (“arm lizard”); it reached 23 m in length and 12 m in height (about the length of two large school buses and the height of a four-story…
Approximately 700 species have been named. However, a recent scientific review suggests that only about half of these are based on fairly complete specimens that can be shown to be unique and…
Scientists have conflicting opinions on this subject. Some paleontologists think that all dinosaurs were “warm-blooded” in the same sense that modern birds and mammals are: that is, they had…
Animal lifespans relate in part to their body size and in part to their type of metabolism. Dinosaur lifespans probably varied in length from tens of years to hundreds of years. Their possible…
Some dinosaurs ate lizards, turtles, eggs, or early mammals. Some hunted other dinosaurs or scavenged dead animals. Most, however, ate plants (but not grass, which hadn't evolved yet). Rocks that…
