Hominin vs Hominid
What do these two confusingly-similar terms mean?
The terms ‘hominin’ and ‘hominid’ are used more or less interchangeably in the media, on the internet, and even in academic literature – causing a good deal of confusion. In simple terms, the hominins are a grouping that includes humans and anything more closely-related to humans than they are to our closest relatives, the chimpanzees. In addition to our own species Homo sapiens the hominins include other extinct humans such as the Neanderthals and Homo erectus. It also includes our earlier, more apelike ancestors the australopithecines and Ardipithecus. The hominids are a larger grouping that additionally includes the Great Apes, that is to say chimpanzees, gorillas and orang-utans. Thus all hominins are also hominids, but not all hominids are hominins.
So why are they used interchangeably? In taxonomic terms, ‘hominin’ identifies a grouping known as a ‘Tribe’ and ‘hominid’ a higher-level grouping known as a ‘Family’ (the familiar terms ‘primate’ and ‘mammal’ refer to the still higher-level groupings ‘Order’ and ‘Class’). For a long time it was believed that humans and Great Apes belonged in separate families, and the term hominid was used to describe humans and our near-relatives. However, in the 1960s and 1970s, genetic studies showed that chimpanzees are more closely-related to humans than they are to other apes, and many researchers began include the Great Apes within the hominids. A new terms was needed to replace the old usage of ‘hominid’, i.e. one that would exclude the Great Apes. Accordingly the term ‘hominin’ was adopted. But not everybody has made the switch, and some continue to use the term ‘hominid’ in its original sense.