Inducement of Torpidity in the Woodland Jumping Mouse

Abstract

During a live-trapping study in a woodland in central New York in June, 1955, a number of woodland jumping mice ( Napaeozapus insignis ) were caught. Of 21 captures of these mice over a five-day period, mice were torpid on nine occasions and active on twelve occasions. The minimum daily temperatures recorded for these five days at the weather station on the Cornell University campus ranged from 48° to 57° F. The area trapped was about 500 feet higher in elevation than the Cornell campus and temperatures were probably somewhat lower. In addition, three of the days were rainy, and on these days a greater percentage of mice were found torpid. The torpid mice were usually in the typical position previously noted by past observers. The snout was tucked between the hindlegs and the animal had assumed a ball-like shape. Other observers have noted that the tail was usually coiled like a watchspring in hibernating mice. Coiling of the tail was not always present in torpid mice in these observations. Awakening reactions were similar to those described by other writers. The animal, upon being warmed and handled, began to revive. Violent shaking usually accompanied this revival. The sense of balance seemed …