Tens of thousands of frogs have appeared on suburban roads in Wuhan and Nanjing, prompting fears among residents that they could be signalling an imminent earthquake. However, earthquake authorities in both cities say that massed ranks of the amphibians do not herald quakes. A resident in the town of Dunkou in Wuhan, the capital of Hubei province, found the road in front of her home covered with thousands of tiny brown frogs, each about the length of a thumbnail, on Monday morning. 'They are packed so densely that it's easy for people to stamp on them, leaving a horrific situation,' she told the Wuhan Evening News. She said she had to use a broom to drive away some frogs trying to enter her house. Other villagers said the frogs began to gather on the road on Sunday night and many had been squashed by cars. The woman, who lives in Dunkou, said she was worried because she had heard that animals often acted strangely before a quake and she wondered if the frogs were an omen. Residents of the town of Jiangxinzhou in Nanjing, Jiangsu , about 600 kilometres away, have encountered a similar phenomenon, the Modern Express reports. One resident said she was astonished to see a large number of small frogs near her home on Saturday morning. A Jiangsu Earthquake Bureau official was quoted as saying that the gathering of frogs was a normal phenomenon and there was no need to panic. 'Animals like chickens, dogs and cats will actually exhibit abnormal behaviour before earthquakes. But it doesn't mean that once animals behave unusually there will necessarily be an earthquake because there are many factors that can cause animals to act strangely,' the official said. A Hubei Earthquake Bureau official said the frogs were gathering on roads because their natural habitat had been reduced. However, the public panic is not completely baseless. Two days before the deadly Wenchuan earthquake in Sichuan in 2008, the West China City Daily reported that hundreds of thousands of frogs had been seen on the roads of Mianzhu, which was wrecked by the quake. Fan Xiao, a Sichuan-based geologist, said the behaviour of animals was not enough to conclude that an earthquake was imminent and scientists needed to consider other factors, monitoring magnetic and electric fields, the earth's crust and underground water. He said it was hard to predict earthquakes and people were better off focusing on building quake-resistant housing and regularly staging quake survival drills.