Ornate box turtles more often than not excavate their own hibernacula. Digging begins with the excavation of a shallow form which is deepened or extended horizontally over a period of days or weeks. Such hibernacula are sometimes begun at the edges of rocks or logs; the overhanging edge of an unyielding object acts as a fulcrum on the shell and hastens digging. Ornate box turtles are slow but efficient burrowers. Forms in open grassy areas are begun at an angle of 30 to 40 degrees; an adult box turtle requires approximately one hour to burrow far enough beneath the sod to conceal itself but can dig into soft, bare earth much more rapidly. Once a hibernaculum is begun, all four feet are used for its excavation, the front feet doing most of the digging and the hind feet pushing loose earth to the rear. Several turtles were seen entering burrows and dens in late autumn and trailing records showed that some individuals visited several of these shelters in the course of a single day. By means of systematic probing of known hibernacula it was found that they are deepened gradually in the course of the winter. Depth seems to be governed by the temperature of the soil. Hibernacula in wooded or sheltered areas were ordinarily shallower than hibernacula in open grassland. In the autumn of 1953-54 two pens were constructed at the Reservation in order to study hibernation; one pen was on a wooded hillside and the other was on open grassland. Turtles in the grassland pen were in newly excavated hibernacula, just beneath the sod, on October 25 and did not emerge for the remainder of the winter, whereas turtles in the woodland pen were intermittently active until November 10. Correspondingly, turtles in the grassland pen descended to depths of eight and one half and 11½ inches, respectively, whereas those in the woodland pen were covered by a scant six inches of loose earth and leaf litter. In 1954 four turtles were traced (by means of trailing threads) to hibernacula on wooded slopes at the Reservation; two entered permanent hibernacula on November 13 and two remained semiactive until sometime after November 20. All four turtles spent the winter in hibernacula that were not more than six inches deep. Temperatures of the soil at a depth of nine inches were usually slightly lower at the grassland pen than at the woodland pen on a given date. It is probably significant that individuals with trailing devices and individuals in experimental pens furnish the latest records for autumn activity. The unnatural conditions created by confining the turtles in pens restricted the number of hibernation sites that were available to them; although trailing devices did not affect the normal movements of box turtles on the surface of the ground these devices certainly hampered the turtles somewhat in digging. However, it is noteworthy that box turtles are able to move about after mid-November, whether this is of general occurrence under more natural conditions or not.