Reproductive biology of the Iberian hare, Lepus granatensis, in Portugal

Abstract

The Iberian hare (Lepus granatensis) is endemic to Iberia. Its distribution range covers most of the Iberian Peninsula and it is one of the most important local game species. However, information on several aspects of its biology, e. g., reproductive patterns, is scarce, limiting our ability to establish a sound management. Therefore, study of Iberian hare reproduction was carried out to: a) determine basic reproductive parameters; b) evaluate seasonal variation of breeding activity; and c) estimate annual productivity. Hares were captured every two months, from mid 1997 through 1999, in southern Portugal. In males, testes position, testes and epididymides weight, daily sperm production, extra-gonadal sperm reserves and serum concentration of testosterone were recorded. In females, weight of ovary, pregnancy rate, litter size, number of corpora lutea and placental scars, intra-uterine mortality, and potential production of young were assessed. Pregnant females and sexually active males were observed in all samples, indicating reproductive activity throughout the year. Mean testis weight was higher than 5 g in all sampled periods. The average numbers of daily sperm production and extra-gonadal sperm reserves were 356 × 106 and 1769 × 106 sperm cells, respectively. Testicular activity in males with intra-abdominal testes was established. Mean litter size, based on the number of embryos, was 1.56 ± 0.10 (range between 1 and 4). A significantly higher number of corpora lutea than embryos was observed in pregnant females. Pre-natal mortality (due to loss of ova and resorption of embryos) in pregnant females with at least one embryo was 21%. The proportion of pregnant females with pre-natal mortality was 26%. The estimated annual potential production of young (9.8) was similar to values observed in other hare species.