Reliability of placental scar counts in the Red fox {Vulpes vulpes L.) with special reference to fading of the scars

摘要: The use of placental scar counts in determining litter size and pregnancy rate among Red foxes (Vulpes vulpes L.) is reviewed. There no experimental material to test the validity method, although many authors have discussed it. Recent workers (1) included uteri from vixens killed later season and, (2) become more concerned about effects resorptions and/or abortions on counts, as well possibility scars persisting earlier pregnancies. In present study, overestimated numbers corpora lutea a higher degree old than yearlings; were shown fade over winter. Estimates frequency breeding females, based various combinations different shades, date death, are discussed. relation between number death known minimum three wild one captive vixen compared with foregoing. Counts all evidently overestimate at birth frequency, probably because some originate resorption sites others persist Only dark should be counted early season, but those increasingly lighter shade winter progresses. A guide counting presented.