História natural das serpentes Oxibelis aeneus (Wagler, 1824) (Squamata, Colubridae) e Philodryas nattereri Steindachner, 1870 (Squamata, Dipsadidae) em domínio de caatinga no estado do Ceará

Abstract

It is presented a detailed study on the ecology of two species of snakes that occur on the state of Ceará, Oxybelis aeneus (Wagler, 1824) and Philodryas nattereri Steindachner, 1870. Both species could be found in the field during all months of the year, O. aeneus presented a peak during the dry season while P. nattereri were more easily found during the raining season. Both presented diurnal activity but O. aeneus is active during the less warm hours of the day while P. nattereri is found during the warmer hours. About their dietary ecology we found that O. aeneus is a lizard-specialist that feed on frogs occasionally, there are no ontogenetic changes on this species diet and P. nattereri is a generalist predator with ontogenetic change in diet, once the adults feed on more categories of prey than the juveniles. We found that the reproductive cycle for females of O. aeneus goes from January to July and males present a pre-nuptial cycle. We found no sexual dimorphism in tail length for this species and females are usually heavier than the males. The reproductive cycle of P. nattereri is extended to females, from February to October and males apparently produce sperm continually. We found sexual dimorphism in tail length and mass, with male P. nattereri having relatively longer tails and females being heavier.