Which trait of this sloth gave name to its taxonomic family?
The living sloths belong to one of two families, known as the Megalonychidae ("two-toed" sloths) and the Bradypodidae (three-toed sloths). The name should in fact be rather "two fingered" or "three fingered" as all living sloths have in fact, three toes on their feet, and differ by the number of fingers on their arms (which were considered front feet in the past).