More than two million Nigerians have been forced from their homes by this year's floods, officials say.The National Emergency Management Agency (Nema) says the heavy rains killed 363 people since July.The worst floods in five decades have affected many areas of the country - especially near the River Niger.The BBC's Will Ross in Lagos says waters are now receding but there are fears over food supplies as some farmers saw all their crops destroyed.President Goodluck Jonathan last month called the floods a "national disaster" but said it would not cause a food crisis, reports the Reuters news agency.Our correspondent says that poor drainage in Nigeria's cities makes flooding likely after heavy rainfall.In some rural areas people said they were frightened after seeing crocodiles, snakes and even hippopotami inside flooded homes.