of these deer include tigers, leopards, clouded leopards, pythons, crocodiles, dholes, Asiatic black bears, fishing cats, Asian golden cats and golden jackals. Foxes, raptors and wild boars prey on fawns. They are highly alert creatures. When put into a stressful situation or if a predator is sensed, muntjacs begin making a bark-like sound. Barking was originally thought of as a means of communication between the deer during mating season, as well as an alert. Reproduction The Southern red muntjacs are polygamous animals. Females become sexually mature during their first to second year of life. These females are polyestrous, with each cycle lasting about 14 to 21 days and an estrus lasting for 2 days. The gestation period is 6–7 months and they usually bear one offspring at a time, but sometimes produce twins. Females usually give birth in dense growth so that they are hidden from the rest of the herd and predators. The young leaves its mother after about 6 months to establish its own territory. Males often fight between one another for possession of a harem of females. Muntjacs are distinguished from other even-toed ungulates in showing no evidence of a specific breeding season within the species. Adults exhibit relatively large home range overlap both intersexually and intrasexually, meaning that strict territorialism did not occur but some form of site-specific dominance exists. Evolution and genetics Paleontological evidence proves that Southern red muntjacs have been around since the late Pleistocene epoch at least 12,000 years ago. Scientists are interested in studying muntjacs because between species, they have a wide variation in number of chromosomes; in fact, the southern red muntjac has the lowest recorded number of chromosomes of any mammal, with males having a diploid number of 7 and females having 6 chromosomes. They are the oldest known members of the deer family, and the earliest known deer-like creatures had horns instead of antlers, but the muntjac is the earliest known species to actually have antlers. Ancestor to muntjacs is the Dicrocerus elegans, which is the oldest known deer to shed antlers. Other fossils found that deer species experienced a split of the Cervinae from the Muntiacinae, the latter of which remained of similar morphology. Muntjacs of this time during the Miocene were smaller than their modern counterparts. Molecular data have suggested that Southern red muntjacs and Fea's muntjacs share a common ancestor, while giant muntjacs are more closely