Iranian Hyrcanian forests were reclassified by Nilson and Andrén in 1984 to Elaphe persica, now Zamenis persicus. According to fossil evidence, the species' area in the warmer Atlantic period (around 8000–5000 years ago) of Holocene reached as far north as Denmark. Three specimens were collected in Denmark between 1810 and 1863 on the southern part of Zealand, presumably from a relict and now extinct population. The current northwestern Czech population now is considered an autochthonous remnant of that maximum distribution based on the results of genetic analyses (it is closest genetically to the Carpathian populations). This likely applies also to the German populations. There are also fossils showing that they had UK residency during earlier interglacial periods but were driven south afterwards with subsequent glacials; these repeated climate-caused contractions and extensions of range in Europe appear to have occurred multiple times over the Pleistocene. Escaped populations in Great Britain There are three populations of Aesculapian snake which derive from escapes in Great Britain. The oldest recorded of these is in the grounds and vicinity of the Welsh Mountain Zoo near Conwy in North Wales. This population had persisted and reproduced since at least the early 1970s, and in 2022 the population was estimated at 70 adults. A second, more recent population was reported in 2010 to be along the Regent's Canal near London Zoo, living on rats and thought to number a few dozen, limited by the scarcity of egg-laying sites. It is suspected this colony may have been there some years, undetected. It is not a harmful invasive species, and the population was thought likely to become extinct. In 2020, a third population was confirmed in Britain being present in Bridgend, Wales. This population has persisted for approximately 20 years. Habitat The Aesculapian snake prefers forested, warm but not hot, moderately humid but not wet, hilly or rocky habitats with proper insolation and varied, not sparse vegetation that provides sufficient variation in local microclimates, helping the reptile with thermoregulation. In most of their range they are typically found in relatively intact or fairly cultivated warmer temperate broadleaf forests including the more humid variety such as along river valleys and riverbeds (but not marshes) and forest steppes. Frequented locations include places such as forest clearings in succession, shrublands at the edges of forests and forest/field ecotones, woods interspersed with meadows etc. However, they generally do not avoid human presence, being