the sewer rat you describe... just some details...

they can swim in water for 75 mins, can also enter houses etc through the pipework... mostly the toilet...

they can see in the dark with ultrasonic (same as bats) and can jump 6ft from standing. they can also withstand high electricity current and bite through sheet steel... they can also eat through conrete, brick etc... and can consume anything organic... including their own.

now thats an efficient animal !