Growth and Development of the Teeth and Skull of the Wild North American Badger, Taxidea taxus

Abstract

Skulls and dentitions (about 68 immature badgers and nearly 900 of yearlings or older) were examined to study growth and development of badgers, Taxidea taxus. In tooth replacement the upper posteriormost deciduous premolars are shed before the middle ones but later than the anterior ones and the canines. In old badgers numerous teeth may be lost. Permanent teeth are truncated by wear, except the canines which sharpen themselves. The development of the skull, described and figured, is most rapid in juveniles and young. In Juveniles underscribed ridges are evident on the maxillary bones of the palate. The dentaries fuse augmenting the locking of the condyloid process and sharpening of the canines. Juvenile (about one month), Young (1-6 months, until weaning), Subadult (7-12 months), Adult (yearlings) and Old Adult (several years) age classes are defined mainly on characters of cranial fusion and tooth replacement. Young show some teeth replacement but retain an open basioccipitalbasisphenoid suture. This closes in Subadults, but the nasal sutures persist and all the milk teeth are shed. Old Adults show a sagittal crest, robust postorbial processes, much tooth wear, and all nasal sutures fused. Trans. Kans. Acad. Sci. Vol. 77 (2), 1974. INTRODUCTION Information on growth in wild carnivores is scarce. Rarer than herbivores, and usually tOO large to raise in numbers in captivity, carnivores of known age are difficult to obtain. The North American badger presents additional obstacles to study: its fierce and solitary behavior, low reproductive rate, winter torpor, fossorial habitats, and sexual dimorphism (Long, 1972). Mearns (1891) discussed some changes in the skull of Arizona badgers. Wright (1966, 1969) reported numerous important findings on aging and growth of badgers (body weight, eye lens, baculum, testes weight, annual dental rings) which augment my information on the nature of growth of the skill. Crowe and Strickland ( 1975) also reported data on annuli of the canine, none present in young of the year and four or more in badgers with worn canines. N1aterials and lN1ethods Cleaned skulls were examined in a taxonomic study mostly in the summer of 1963, in the Bird and Mammal Laboratories, U.S. National Museum. Records were compiled when possible of age and changes in skull and dentition. Broken skulls provided information on the inner parts of the cranium. Numerous immature specimens were examined (only 5 juveniles, 39 young) as well as Transactions of the Kansas Academy of Science, Vol. 77, No. 2, 1974. Published August 15, 1975.