Today only two types of proboscidae remain on earth.  They are both tropical in nature, but they come from areas that are quite separate geographically.  One type lives in Asia and one type in Africa. 

Although they are superficially similar, it is actually very easy to tell them apart.  In the pictures above, note that the back of the Asian Elephant arches upward right from its shoulders to its hips.  The back of the African Elephant slopes down over its shoulders forming a more gradual arch that rises over the hips.  Additionally, note that the African Elephant has larger ears than the Asian Elephant, whereas the Asian Elephant has a more pronounced forehead than the African Elephant.  Lastly, both males and females of African Elephants have pronounced tusks that are clearly visible.  In Asia, you usually don’t see tusks on females. 

You can even tell the species apart by looking at the tips of the trunks alone.  The African Elephant’s trunk has two finger-like projections that it uses for manipulating material.  The trunk of the Asian Elephant has only one such projection. 

Note the single "finger" on the trunk tip of the Asian Elephant

Their evolutionary lines of these two elephants have been separate for about 5 million years.  This makes them no more closely related than zebras and horses.  In fact, evidence suggests that Asian Elephants were more closely related to extinct wooly mammoths of the past than they are to African elephants of today. 

Anatomical similarities suggest the Woolly Mammoth was more closely related to the Asian Elephant (right) than it was to the African Elephant (left)

Perhaps that explains why Asian Elephants are sometimes much hairier than their African counterparts. 

 
photo M. Noonan

It is an exciting time to be an elephant biologist!  Consideration of the phylogeny and taxonomy of elephants has become even more interesting lately.  Within Africa, there are consistent differences between the elephants that inhabit the savannah and those elephants that inhabit thick forests.  At the very least, these two types can be recognized as different subspecies.  However, the differences are great enough that many elephant biologists now consider it reasonable to classify these African elephants as two entirely separate species:  the Savannah African Elephant and the Forest African Elephant.  If this idea gains widespread support, we may soon say we have three species of living proboscidae -- two in Africa and one in Asia.