The fossa is the largest carnivore on Madagascar and one of the numerous endemic species of this island. Though recent studies1,2 have increased the awareness of the peculiarity of this endangered species (IUCN, Red List), there is still little known about its reproductive biology. The aim of the present study was to describe the anatomy of the inner sexual organs and to provide further evidence for the seasonality of their reproduction.
Thirty-one (16.15) captive fossas were examined both during the reproductive season in spring and during the non-reproductive season in autumn. Ultrasonographic examination of the reproductive organs, hormone analysis, semen evaluation, pheromone analysis, and a genetic assessment were performed.
Preliminary results allowed for the sonomorphologic description of the normal reproductive tract. However, a high number of individuals (2 of 16 males and 7 of 15 females) showed reproductive disorders and/or pathologies,3 such as cystic structures or poor development of the genital tract in females and unilateral cryptorchism in males. Results from the genetic studies will provide information if the observed pathologies might be linked to inbreeding within the captive population. The seasonality of reproduction could be supported by hormone, semen,5 and volatile4 analyses. Mean values of testosterone in male individuals (15.32±8.05 ng/ml versus 0.73±0.74 ng/ml) as well as estrogen in female individuals (0.47±0.37 ng/ml versus 0.03 ±0.01 ng/ml) were significantly higher in spring versus autumn. These findings were reflected by a higher semen quality during the breeding season versus the non-breeding season; characterized by the semen parameters volume (420±496.06 versus 149.17±96.15 µl), total sperm number (8.04±18.69 versus 2.30±2.54×106 cells/ejaculate) and motility (57.41±8.72 versus 37.05±12.71%). The volatile analysis revealed gender specific differences in volatile expression (total quantity and pattern of substances) that were apparent only in spring.
In conclusion, the reproductive organs of the fossa were described and additional proof for their reproductive seasonality was given. Further examinations will be performed to consolidate the data. A future aim is the comparison of the data obtained from the zoo population to that of the wild population.
The authors thank the zoos of Amsterdam (NL), Berlin (GER), Bratislava (SK), Chemnitz (GER), Colchester (GB), Duisburg (GER), Dvur Králové (CZ), Frankfurt am Main (GER), Olomouc (CZ), Ústí nad Labem (CZ) for assisting with research on their fossas and collecting sample material as well as the Center for Conservation and Research (CCR, Omaha, USA) for their assistance with genetic analyses. Special thanks to: L. Dickie, S. Engberg, M. Garcia Hartmann, E. Louis, V. Pozivil, and A. Winkler and many others. Kathrin Paschmionka and Marlies Rohleder of the IZW supported the study by helping with laboratory work and Dagmar Viertel by creating electron microscopic images.
1. Dickie, L. 2005. The behaviour and reproductive physiology of the fossa (Cryptoprocta ferox) in captivity. PhD thesis, University of London.
2. Hawkins, C. 1998. Behaviour and ecology of the fossa, Cryptoprocta ferox (Carnivora: Viverridae) in a dry deciduous forest, western Madagascar. Pergamon Press, Oxford, UK. Pp. 239.
3. Vogler, B.R., F. Goeritz., G. Fritsch, M. Garcia Hartmann, R. Hermes, K. Jewgenow, V. Pozivil, A. Ochs, A. Winkler, and T.B. Hildebrandt. 2005. High incidence of reproductive disorders in captive fossas (Cryptoprocta ferox). International Symposium on Diseases of Zoo and Wild Animals (42):304–307.
4. Vogler, B.R., F. Goeritz, T.B. Hildebrandt, and M. Dehnhard. 2006. Gender specific expression of volatiles in captive fossas (Cryptoprocta ferox) during the mating season. Chemical Signals in Vertebrates 11 (abstract, submitted).
5. Vogler, B.R., F. Goeritz, T.B. Hildebrandt, R. Hermes, C. E. Reid, K. R. Roellig, B. Drews, S. Blottner, and K. Jewgenow. 2006. Seasonal changes in semen quality in the fossa (Cryptoprocta ferox). Reproduction in Domestic Animals—Special edition for the 39th Annual Conference on the Physiology and Pathology of Reproduction in Hannover, Germany (abstract no. 137).