As for the foot click--a presumptive means of communication (_cf._ Seton, 1929, +3+: 69; Jacobi, 1931: 212-216)--I must confess that I was always so engrossed with photography whenever the Caribou were close at hand (up to within a dozen feet) that I had no thought of this phenomenon and did not detect it. _References._--Richardson, 1829: 242; A. J. Stone, 1900: 53; Preble, 1902: 42; Seton, 1929, +3+: 105; Murie, 1939: 245; Harper, 1949: 230; Banfield, 1951a: 19, 27. _Food_ The ground lichens (including the various species of _Cladonia_) in the Windy River area in 1947 did not seem, for the most part, to have a height of more than 2 or 3 inches. The average length of several local specimens of _Cladonia_ is approximately 51 mm. This condition was in considerable contrast to the great spongy masses I had noted in the Tazin River basin, between Athabaska and Great Slave lakes, in 1914. I have no means of knowing whether the condition in Keewatin represented severe cropping by Caribou in past years and subsequent slow recovery, or whether it is a normal condition. According to Charles Schweder, the growth depends upon rain, and so varies from year to year. During the warmer months, from June to September, the local Caribou seemed to me to be feeding very largely on the higher vegetation, such as willow, dwarf birch, alder, and sedges. I had no definite evidence of their consuming lichens during that period. By early October the species of _Cladonia_ seemed to have attained a somewhat fuller growth than they had exhibited several months previously. Perez-Llano discusses (1944: 29-30) the utilization by Reindeer of various lichens. Dix has reported (1951) on a collection of lichens from the Windy River area. Some miscellaneous observations along Windy and Little rivers follow: June 16, 20 Caribou feeding apparently on patches of crowberry (_Empetrum_) and dwarf birch (_Betula glandulosa_) on a ridge; June 29, a Caribou feeding apparently on dwarf birches; June 30, a buck grazing in a sedge bog; August 26, several bucks browsing on willow tops (probably _Salix planifolia_) in a riverside thicket, and some does on dwarf birch and perhaps tall grass or low willow; August 27, numbers feeding largely on willow and dwarf birch; August 28 and 30, low alders, willow, and dwarf birches nibbled off. By early October the leaves of the three last-mentioned shrubs were no longer available, having dropped off. During the summer they had seemed to be preferred above the lichens. Cabot has remarked (1912: 46) on the fondness of _Rangifer arcticus caboti_ for dwarf birch in Labrador.