Extract Madam: — Brushtail possums transmit bovine tuberculosis (Mycobacterium bovis) to cattle in New Zealand. (2) Davidson, R.M. 1976. The role of the opposum in spreading tuberculosis. New Zealand Journal of Agriculture, 133: 21–25. [Google Scholar] In the laboratory the infection can spread from possum to possum by droplet infection (1) Bolliger, A. and Bolliger, W. 1948. Experimental transmission of tuberculosis to Trichosurus vulpecula. Australian Journal of Science, 10: 182–183. [Google Scholar] but little is known about infection routes in the wild. It is widely supposed that shared dens provide sites for transmitting tuberculosis among possums, (4) Julian, A.F. 1981. “Tuberculosis in the possum Trichosurus vulpecula”. In Marsupials in New Zealand, Edited by: Bell, B.D. 163–174. Zoology Publications, Victoria University of Wellington. In, No. 74 [Google Scholar] but there is little hard information on den-sharing in the scientific literature. Winter (6) Winter, J.W. 1976. “The behaviour and social organisation of the brush-tail possum (Trichosurus vulpecula: Kerr)”. In Ph. D thesis, University of Queensland. (unpublished) [Google Scholar] inspected possum dens in Queensland eucalypt forest on 783 occasions and found adult animals shared these sites on 23 occasions. At the most, two adult animals shared these dens. Jolly (3) Jolly, J.N. 1977. Movements and social behaviour of the opossum Trichosurus vulpecula Kerr, in a mixed scrub-bush and pasture habitat. Mairo Ora, 1: 65–71. [Google Scholar] noted a pair of males in a single shelter on Banks Peninsula. Pracy (5) Pracy, L.T. 1974. Opossums. New Zealand's Nature Heritage, 3: 873–882. In Knox, R. (Ed.) [Google Scholar] reported that “instances of more than three opposums occupying the one nest have been observed frequently where populations are at high or peak levels”.