The River Thames, which was once a sort of combined open sewer and industrial waste pipe abhorrent to all forms of life apart from the hardiest strains of the E. coli bacteria, is now teeming with proper animal life thanks to decades of us being more careful about what gets pumped into it.
The Zoological Society of London says there have been numerous reports of seals being spotted at Canary Wharf, with dolphins hanging around Deptford and occasionally venturing as far upstream as Teddington in the west – and over 2,700 assorted large fish-eating behemoths including porpoises and whales counted by spotters hanging about beside the water's edge over the last decade.
The ZSL says the presence of these outwardly cuddly things is good news because they're actually killer predators on the inside, ones that feast on the fish that can now live in the river because we've stopped indirectly pooing in it. ZSL conservation manager Joanna Barker says: "People are often surprised to hear that marine mammals are regularly spotted in Central London. As a top predator, their presence is a good sign that the Thames is getting cleaner and supporting many fish species. The presence of these animals is also a great example of how urban environments are important for wildlife." [ZSL via BBC]