Hominid - Why Are Some Scholars No Longer Using that Term?

Why Have Scientists Changed What We Call the Human Race?

Reconstruction of Australopithecus afarensis
The face of 'Lucy,' an Australopithecus afarensis and part of the 'Evolving Planet' exhibit, is displayed at the Field Museum March 7, 2006 in Chicago, Illinois. Tim Boyle / Getty Images News / Getty Images

Hominid is a general term which has been used for decades by archaeologists and paleontologists to stand for all modern humans and any member of the species of animal we are most closely evolved from, currently including Homo erectus, Neanderthals, Denisovans and Australopithecines. However, beginning in the mid-1970s and slowly growing into the present day, growing proportions of the scientific community has shifted to using "hominin" for well, let's face it, essentially the same thing.

In a totally unscientific poll which might actually be a poxy (oops, proxy) statistic, I asked Google Scholar--Google's search engine built specifically for academic books and articles--to give me references for the separate terms hominid and hominin in five year chunks for the past 40 years, and here's what I found out.

Hominid, Hominid: What Does Google Scholar Say?
YearsN  homininN  hominid% hominin
2011-201510,20013,70074.5%
2006-20104,89013,50036.2%
2001-20051,14010,50010.9%
1996-20001306,4202.0%
1991-1995274,5400.6%
1986-1990203,2700.6%
1981-1985102,6700.4%
1976-198041,7600.2%

In this table, the number in the hominin column is the number of articles listed in Google Scholar for that period that use the word "hominin" and the hominid column is that for hominid. There's probably overlap, and since we know that a lot of the scholarly research before the 21st century has yet to be placed on the Internet, I'll stop at 1975: but the percentages are telling.

 

So, Why Change the Name?

The first fossil hominid specimen on record was discovered in 1830--it was what we would call a Neanderthal; each year since more and more fossil remains have been and are being recovered and more techniques are being created to learn more and more about those fossil humans.

Ever since Darwin's ground breaking book The Origin of Species, biologists and palenontologists have been trying to classify the family of humans out of those thousands of fossilized fragments--not forgetting, of course, our primate cousins. We've known for a while that apes are related to us, but how closely? Where in the family tree do they belong?

The first taxonomic structure for humans and our relatives began with the Primate family, and under that family was classified the Hominoids, split into two subfamilies:

  • Anthropoids: chimps, gorillas and orangutans
  • Hominids: humans and their immediate ancestors

What Bucket Do They Fit Today?

The earliest decisions about which primate fit in which evolutionary bucket were made on physical characteristics. In general, a fossil ape is identified as a human ancestor, in general, if it stood on two legs (was bipedal), and had relatively smaller teeth and bigger brains than the rest of the apes.

Beyond that, ancient fossils were grouped together if they looked alike, if they shared consistent characteristics. What characteristics are the important ones--a distinct chin or evidence of stone tool production or a sagittal crest--is part of the growing field of "homology".

But which characteristics, in which species? In the 1960s, Michael Goodman proposed that "Hominidae" should include gorillas, monkeys, and humans. Others suggested "Hominini" but that it should include chimps in with the humans.

New Sources of Information

In a chapter of the Handbook of Paleontology published in 2007, paleontologist Jean-Jacques Hublin laid out several advances in the science of paleontology that both complicate our categories and make them at least potentially resolvable. Here are a few that he mentions:

  • virtual paleontology, including computed tomography and the production of three dimensional images of fossil specimens, allowing researchers all over the world to study the same fossil remains at the same time without leaving home
  • virtual correction of plastic distortions
  • analysis of previously inaccessible internal structures, like the middle and inner ears
  • modeling of evolutionary changes over time
  • microstructural studies of bones and teeth
  • chemical analysis of organic molecules, including mitochondrial DNA
  • studies on the taphononomical processes that affect DNA deterioration
  • stable isotopic composition of hominid bones, that provide information about the diet and environment
  • new chronological methods
  • advanced techniques in soft tissue reconstruction, including muscles, skin, hair and eyes

As you might imagine, as the science grows, as data collection and data manipulation becomes more available, scholarly debates will develop and those of us in the public will have to learn to embrace the fact that change is what science is all about.

Many paleontologists have begun using the term Hominin for this group. See the article on hominin for a discussion on what scholars have decided--so far.

Sources

This article is a part of the About.com guide to the Paleolithic, and the Dictionary of Archaeology.

Cela-Conde CJ. 2001. Hominid Taxon and Systematics of the Hominoidea. In: Tobias PV, editor. Humanity from African Naissance to Coming Millennia: Colloquia in Human Biology and Palaeoanthropology. Florence; Johannesburg: Firenze University Press; Witwatersrand University Press. p 271-279.

Howell FC. 1999. Paleo-Demes, Species Clades, and Extinctions in the Pleistocene Hominin Record. Journal of Anthropological Research 55(2):191-243.doi: 10.2307/3631209

Hublin J-J. 2007. Prospects and pitfalls. In: Henke W, Tattersall I, and Hardt T, editors. Handbook of Paleoanthropology.

Berlin: Springer-Verlag. p 815-829.

Lieberman DE. 1999. Homology and hominid phylogeny: Problems and potential solutions. Evolutionary Anthropology: Issues, News, and Reviews 7(4):142-151. doi: 10.1002/(SICI)1520-6505(1999)7:4<142::AID-EVAN4>3.0.CO;2-E

Tattersall I. 2012. Higher taxa: An alternate perspective. Evolutionary Anthropology: Issues, News, and Reviews 21(6):221-223. doi: 10.1002/evan.21329

Underdown S. 2006. How the word 'hominid' evolved to include hominin. Nature 444(7120):680-680. doi: 10.1038/444680d