A pet door having a casing and a door assembly contained within the casing, the door assembly having a plurality of rotatably interlocking segments such that the door assembly is rigid in a direction along an axis of rotation of the interlocking segments and flexible along a second axis perpendicular to the axis of rotation of the interlocking segments, and a plurality of end caps for preventing horizontal sliding of individual interlocking segments, the end caps having a first surface which engages the end of the interlocking segments and a recess surface spaced away from the end of the interlocking segment to allow free rotation of the interlocking segment not engaging the first surface of the end cap. The pet door further includes a magnet positioned in the end caps which are aligned with a corresponding magnet positioned along the sides of the casing member to individually position the interlocking segments in the casing.
