The behaviour and reproductive physiology of the fossa (Cryptoprocta ferox) in captivity
The fossa (Cryptoproctaferox) is a solitary carnivore and the largest endemic mammal extant on Madagascar. It is estimated that less than 2500 individuals survive on the island and they are currently listed by the IUCN as endangered. The aims of this study were to investigate the behaviour and reproductive physiology of the fossa, with reference to the small captive population. The limited previous work carried out on this species suggested several unique traits both in biology and behaviour. Of particular note is the phenomenon of transient masculinisation observed in juvenile females, and in addition, the highly unusual mating system described as a cross between lekking and scramble competition polygyny. In this present study six zoos were visited in the UK and Germany to observe fossa behaviour. General behavioural observations were used to gather data on activity patterns and budgets, the occurrence of repetitive pacing, reproductive behaviour and scent-marking in both males and females. Furthermore, enclosure modification was used to examine in greater detail aspects of behaviour noted. Five zoos collected faecal samples over a threeyear period; these were used to study reproductive physiology through the application of an enzyme immunoassay technique. In addition, museum specimens of bacula, in both the fossa and other carnivores, were examined in relation to function and described mating systems. Seasonality, ovulation type and the length of the oestrus cycle were determined and behavioural changes linked to reproductive condition found. A new theory, termed transient natal dispersion, is proposed to explain the unusual mating and social system Aerv d, incorporating information gathered regarding ovulation, copulatory pattern, scent-marking behaviour and the male genitalia. The data gathered in this study are also used to propose changes in management, which would enhance the keeping of this endangered species, whilst the future role of zoos in carnivore conservation is reexamined.