Eldredge began his undergraduate studies in Latin at Columbia University. Before completing his degree he switched to the study of geology under Norman D. Newell. It was at this time that his work at the American Museum of Natural History began, under the combined Columbia University-American Museum graduate studies program.
In 1969, Eldredge became a curator in the Department of Invertebrates at the American Museum of Natural History, and subsequently a curator in the Invertebrate Paleontology section of Paleontology, a position from which he recently retired. He was also an Adjunct Professor at the City University of New York. His specialty was the evolution of mid-Paleozoic Phacopida trilobites: a group of extinct arthropods that lived between 543 and 245 million years ago.
"Don't walk one step ahead of her with your head down."
"We have a conservative religious element in the United States that is opposed to the notion that we are connected to the rest of the natural world, especially apes."