London: Surviving all kinds of environmental changes, hedgehogs -- the 15 million years old species -- have adapted to city life more than the rural areas, says a new study. The findings showed that cities have higher hedgehog numbers than rural areas. Hedgehogs were also found to have adjusted their activity to levels of human disturbance with much smaller nightly ranging areas of five hectares than their rural counterparts with 50 hectares. While the city hedgehogs mainly stayed in private gardens during the day but around midnight, when the number of humans and pets in local parks decreased, they came out to forage and look for mates. This shows the importance of gardens or parks for them to remain undisturbed for the entire hibernation season as well as for their future survival, the researchers said. "Gardens and public parks are very important for city hedgehogs. They need gardens with natural vegetation and public parks less immaculately pruned, with plenty of natural, bushy areas," said lead researcher Lisa Warnecke from University of Hamburg in Germany. Further, urban hedgehogs seemed to have similar pattern of hibernation to rural populations. During winter season, hedgehogs enter a physiological state called torpor, where their metabolic rate and body temperature decrease significantly in order to save energy. "This was despite city hedgehogs often nesting next to busy roads and having potential food sources available throughout winter - such as food scraps or cat food on private terraces," Warnecke added. City dwellers should take care to avoid disturbing nesting hedgehogs and to keep their gardens free of anything that could do them harm, the researchers suggested. "Our work with the hedgehog care station showed that the main problems were injuries caused by fences, plant netting or gardening tools and sickness from ingesting rat poison," Warnecke noted. For the study, the team fitted free-ranging hedgehogs with temperature-sensitive transmitters to investigate what physiological factors allow them to thrive in urban areas. The results were presented at the Society for Experimental Biology's Annual Meeting held at London, recently.