rates ranging from 10.6 to16.2%. Chytridiomycosis has been observed to affect the calling of H. japonica in a multitude of different ways. Number of pulses per note and note duration were both observed to be significantly higher in infected H. japonica compared to uninfected H. japonica. The increased effort devoted to reproductive efforts by infected H. japonica is an interesting result that warrants further research. Two hypotheses have been proposed to explain the observed behavior. First, this increased investment towards reproduction might be a result of Batrachochytrium dendrobatidis driving increased reproduction in order to increase spread of infection. Another hypothesis is that H. japonica increases its reproductive effort in the event that they die earlier due to Chytridiomycosis. This behavior would increase the chance of reproductive success by propagating their genes before they die. Heterospecific amplexus H. japonica have been observed with Pelophylax chosenicus in amplexus. Both species inhabit rice paddies and this shared habitat is a possible explanation for the observed interspecies copulation. Mating between different, but closely related species can sometimes result in hybridization. Further work is required to uncover the extent of heterospecific amplexus between H. japonica and Pelophylax chosenicus. Enemies Predation by the American bullfrog Lithobates catesbeianus, colloquially known as the American bullfrog, is an exotic predator of H. japonica. Predation by L. catesbeianus has been shown to significantly decrease the bone mineral density of H. japonica. Because bone mineral density can be used as a proxy for food intake, the conclusion that L. catesbeianus predation of H. japonica exerted a predation pressure that reduced food intake of H. japonica can be drawn. Predation by L. catesbeianus was not observed to induce any morphological changes in H. japonica. Physiology Predator defense by toxic peptide secretion H. japonica have evolved against predation in arboreal environments by producing special Anntoxin-like neurotoxins from their skin. Anntoxin is a 60-residue toxic peptide that inhibits ion channels such as tetrodotoxin-sensitive voltage-gated sodium channels. While these peptides display analgesic properties after binding onto ion channels, they can harm and kill predators after frog skin consumption. Such a mechanism deters predators from further frog hunting. Cold resistance H. japonica demonstrates the remarkable ability to withstand extremely cold temperatures. H. japonica is able to survive temperatures as low as -35 °C. The majority of H. japonica individuals in a population from the Amur River were shown to withstand multiple rounds of exposure to -30