We humans have taken a big advantage of our supremacy over other lifeforms on the planet and have caused the extinction of a large number of flora and fauna either by hunting them, destroying their habitat for our own uses ,introduction of our pets, etc. Below is a list of some extinct animals:
Dodo
Quagga
Haast's Eagle
Passenger Pigeon
Woolly Mammoth
Tasmanian Tiger
West African Black Rhinoceros
sad reality.
However, with the mammoth it's debatable. And even if it was human caused those human could not be blamed because they didn't know they were killing their primary food source to extinction.
But it was still their fault anyway.