Rana [Lithobates] catesbeiana Shaw (American bullfrog): Antonia D’Amore

Bullfrogs are the largest frog species in North America and among the largest frogs globally. Females reach slightly larger sizes than males, with adult females growing to average sizes of approximately 16cm SVL and males to approximately 15cm SVL (Howard, 1981). This sexual size dimorphism can vary with features of their introduced climate (Xuan et al, 2010). Due in part to their large size, female bullfrogs lay egg masses with up to 25,000 eggs, up to one quarter of their body mass, during the breeding season in late spring and early summer. The largest females have been recorded as laying more than 40,000 eggs (Bury and Whelan, 1984). These egg masses are attached to emergent vegetation in shallow water and will form large sheets on or just below the surface of the water. Choice oviposition sites are fiercely guarded by males, who fight to establish territories encompassing the best sites. Males are polygynous and mate with females that enter their territories and approach the calling male (Emlen, 1968; Wiewandt, 1969).