Advances in New Zealand mammalogy 1990–2000: Deer

The rapid expansion of deer farming in recent decades has stimulated frequent introductions of new genetic material, either as live animals or as frozen semen (Pearse & Goosen 1999). This has produced a blurring of taxonomic boundaries, a process that is likely to be hastened by deliberate hybridisation between species, e.g. between red and Pere David's deer (see below) and between red and sambar deer (Muir et al. 1997), and by inadvertent hybridisation between supposedly distinct species in captivity (e.g., red and rusa deer on some Australian deer farms: P. F. Fennessy cited in Asher et al. 1999). During 1984 and 1985, 77 Pere David's deer (Elaphurus davidianus) were imported into New Zealand as prospective farm stock (Asher et al. 1988). Most died from malignant catarrhal fever (Orr & Mackintosh 1988). Only about 20 of their descendants survive, at Mt Hutt Station, Canterbury (D. Hood pers. comm. 2000). Although karyotypically similar to red deer (i.e., 2n = 68), Pere David's deer are 50-60% larger than red deer, and have considerably larger hooves, a longer tail, and antlers that characteristically appear to grow backwards. Pere David's deer are long-day (summer) breeders, whereas red deer are shortday (autumn) breeders. Gestation in Pere David's deer is 283 days (Wemmer et al. 1989), about 50 days longer than red deer. Despite the large genetic distance between Pere David's deer and red deer (Tate et al. 1992), hybridisation between the two species was achieved by artificial insemination (Asher et al. 1988; Fenessy & Mackintosh 1992). Between 1986 and 1991, 16 Fj hybrid calves were produced, and these were in turn used to produce over 400 maternal backcross calves (i.e., 25% Pere David, 75% red deer) that have proven to be extremely valuable in mapping the red deer genome (Tate et al. 1997). However, maintaining these populations of hybrids has proven difficult, so they are unlikely to be incorporated into the New Zealand farmed deer population. Remaining Y\ and backcross hybrids are almost wholly confined to research facilities.