Many of the racers examined bore scars from wounds that were probably inflicted by predators. A few had survived severe skeletal injuries, involving deformation of the spinal column or extensive tearing of muscle and connective tissue layers of the body wall, altering the normal body shape. A more frequent type of injury involved chiefly the integument, which had been ripped open by the teeth, claws, or bills of adversaries, despite the fact that the skin is remarkably tough and leathery. Patches of scar tissue with scales in irregular sizes, shapes and patterns characterized such injuries. The most frequently observed type of injury involved loss of part of the tail. Usually only a small terminal part was missing, but occasional stub-tailed individuals had lost as much as three-fourths of the tail. No consistent trend of difference between the sexes in incidence of injuries to the tail was noticeable, but there was definite correlation with age. In the entire sample from the Reservation and Rockefeller Tract the percentages in each supposed age group (actually size group) lacking part of the tail were as follows: hatchlings, 2.9 per cent; one-year-olds, 9.5 per cent; two-year-olds, 15.8 per cent; three-year-olds, 14.3 per cent; four-year-olds, 15.7 per cent; five-year-olds, 23.2 per cent; six-year-olds, 30.9 per cent; seven-year-olds, 28.9 per cent; those eight years old or older, 21.1 per cent. The seeming reversal of trend in the older racers is difficult to explain, but probably results from inadequate numbers in this part of the sample.