until his health failed. Ostrom died from complications of Alzheimer's disease in July 2005 at the age of 77 in Litchfield, Connecticut. Key discoveries In the field of paleontology, Ostrom is responsible for the following key discoveries: Hadrosaurs Ostrom's work first achieved international attention with his studies of the unique hadrosaur nasal apparatus, which had not been convincingly explained by the early 1960s. By examining the olfactory apparatuses of modern reptiles and drawing comparisons via comparative morphology, Ostrom concluded that hadrosaurs likely developed an acute sense of smell by a lengthening of the nasal passages into long chambers that wound around the skull and were protected by bony crests. He speculated in a subsequent paper that hadrosaurs had need for such an acute sense of smell as a defense against larger carnivorous dinosaurs, of which the hadrosaur body plan had little in the way of armor and speed. This hypothesis led Ostrom to further conclude that ecology of hadrosaurs was more likely to be that of dry ground than swampy, aquatic environments, thought to be the case at the time. This idea became justified by a 1922 paper that Ostrom rediscovered in 1964, which described the stomach contents of a mummified specimen of the hadrosaur Anatosaurus, which included conifer needles, twigs, fruit and seeds, plant matter that would be consumed in a terrestrial environment. Ostrom's reading of fossilized Hadrosaurus trackways also led him to the conclusion that these duckbilled dinosaurs traveled in herds. Warm-blooded dinosaurs Due in large part to his earlier research on hadrosaurs—and his conclusion that they were likely upright, terrestrial animals rather than sluggish, swamp-bound lizards—Ostrom was one of the first paleontologists to grasp the implications of the amount of energy it would take such large animals (and their still larger predators, such as Tyrannosaurus rex) to stand and move erect. At the first North American Paleontological Convention, held at the Chicago Field Museum in 1969, Ostrom spoke out against the accepted wisdom that Mesozoic climates were universally tropical and that such warm climates would be necessary to sustain large animals with lizard-like metabolisms. Ostrom supported this view by noting the correlation of erect posture and locomotion with high metabolism and body temperature in modern mammals and birds, stating that this relationship cannot be accidental. The observation that dinosaurs, thought to be uniformly cold-blooded at the time, could not be used as indicators of paleoclimate was further