Complex sentence: One animal that has benefited from endangered species protection is the American Alligator ("Alligator mississippiensis"), whose holes give refuge to other animals, often allowing many species to survive during times of drought.
Split into simpler sentences: One animal that has benefited from endangered species protection in the past is the alligator ("Alligator mississippiensis"). Their holes give refuge to many other animals, often allowing many species to survive during times of drought.