Jay S. Gashwiler

Notes on Cougar Productivity and Life History

Records collected principally from 1946 through 1958 in Utah and Nevada have shown that the cougar may have young any month of the year. However, birth months, as determined by reference of juvenile weights from 145 litters to a growth curve, indicated that about 60 per cent of the litters were probably born from June through September with a peak in July. The highest incidence of pregnancy for 199 mature females was noted in June and July. Forty-one per cent of 299 mature females had young at the time of capture. Evidence is presented that some females apparently have young as often as 12–15 months, but a 2-year interval appears the rule. Most young apparently remain with their mothers for at least a year. The average size of 258 postnatal litters was 2.9 (range, 1–5) and of 66 prenatal litters it was 3.4 (range, 1–6).

Winter Mortality of Mule Deer in Utah in Relation to Range Condition

The winter of 1948-49, one of the severest recorded in Utah since the inception of weather stations, focused the attention of the public upon the welfare of the mule deer (Odocoileus hemionus) herds in the State. Widespread deer depredations on orchards and haystacks and on ornamental shrubbery in cities and towns were indicative of the desperate plight of the herds. The Utah State Fish and Game Commission was besieged with demands that various deer herds be fed. Con-

Breeding Habits of Bobcats in Utah

The sex ratio of trapped bobcats revealed a preponderance of males. Breeding started in January and extended to July or later. Embryos were found each month from January until September—most were in March and April. Embryos ranged in number from 1–8, had a mode of 3, and averaged 3.2. Litter size ranged from 1–6, had a mode of 4, and averaged 3.5 kittens. Placental scars ranged from 3–5, had a mode of 4, and averaged 3.9. Bright yellow corpora lutea ranged from 2–9, had a mode of 5, and averaged 4.8 per female. Birth dates of 13 litters extended from March to July; one September pregnancy was noted. Lactating females were found from March until September, the most in May. Kittens a few to several days old weighed from 4.5–11.6 ounces. There was no indication that males help with the care of young. Females are good mothers and will care for kittens under trying conditions, but if unduly disturbed may sometimes desert the newborn young. Kittens will stay with the female until 2/3 to 3/4 grown. One instance of hybridization between a male bobcat and female domestic cat is reported.

Antlerless Mule Deer Bucks

The few published accounts of antlerlessness in male cervids implies a comparative scarcity of this phenomenon. Accordingly the cases noted by the writers in mule deer males ( Odocoileus hemionus hemionus ) may deserve mention. We are indebted to Dr. George Wislocki of the Harvard Medical School for a reference to antlerless adult male deer recorded in German literature. The following is a direct quotation from his letter of December 8, 1953. “Rorig in 1907 (Gestaltende Correlationen zwischen abnormer Korperkonstitution der Cerviden und Geweihbildung derselben: Archiv f. Entwicklungs-mechanik der Organismen, Bd. 23) on pages 8–10 and 13–14 lists a number of instances known to him or cited in the literature of deer without antlers but with normal genitalia. His compilation relates almost entirely to Cervus elaphus and Capreolus . He said that he found no evidence of anomalies of any sort in the reproductive organs, and there was good evidence that the animals were fertile and sexually active. In one case (and possibly two) the condition appeared to be hereditary because other animals of the same character were observed in the same locality. Adult males with total absence of antlers and abnormal genitalis are extremely rare, according to Rorig. On page 26 he cites an animal of this sort with small cryptorchid testes, and gives fragmentary data on four other cases.” Seton (lives of game animals, Vol. 3, Part 1, p. 239, 1929) states, “I have never seen one (antlerless adult buck) but I have often heard of them and find several cases recorded.” However, he actually cites but two references (J. B. McW., Forest and Stream 46: 454, June 6, 1896; and F. H. K., Forest and Stream 47: 5, July 4, 1896). The present writers have read only the latter reference in which the writer claimed to …

Further Analysis of Methods for Censusing Winter-Lost Deer

Results of a study testing five methods for censusing dead deer were presented by Robinette et al. (1954). The tests were made on restricted units of Utah winter deer range on which there were known numbers of dead deer or randomly placed burlap sacks simulating dead deer. It was concluded that Haynes (1949) modification of Kings grouse census method and Webbs (1942) snowshoe hare census method were not adapted to censusing inanimate objects. Kings grouse census method, the Lincoln Index (Lincoln, 1930), and Kelkers (1945) belt transect method gave acceptable results when certain precautions were taken to eliminate bias.