Which animals are evolving fastest?

The "fastest evolving vertebrate" title is hotly contested, but here are a few contenders.Evolution occurs over millennia, but it can also happen in just a few generations. For example, Darwin's finches in the Galapagos rapidly evolved specialized beaks as their food options changed, green anoles (Anolis carolinensis) evolved larger toe pads that enabled them to climb higher to escape predators, and peppered moths (Biston betularia) became darker colored as the Industrial Revolution polluted cities with black soot.
So which vertebrate animals are evolving the fastest? It's a close call.