By the time New Yorkers spied a dolphin swimming through the superfund sludge of the Gowanus Canal last Friday, it was too late. The marine mammal didn't even survive long enough for a rescue plan to come together. First sighted on Friday afternoon, the dolphin perished at 6:00 p.m.

The reason the marine mammal died, and why the dolphin swam up the polluted waterway in the first place, is as yet unknown. But the sad story of the wayward creature highlights the strange nature of New York City, the global epitome of urbanity. Hidden within Gotham are native carnivores, marine mammals, and even species that have scarcely been seen before.

Marine mammals are arguably the most high-profile of New York City's wild residents and visitors. The Gowanus Canal dolphin was only the latest