Wednesday, June 19, 2013

The Zanzibar Leopard: A Lesson in Island Dwarfism....and Extinction

Very few people have heard of the Zanzibar leopard, unless of course you are a person from Zanzibar, an island ecologist interested in insular leopard populations, or you are another Zanzibar leopard.  (Which might be problematic, being another Zanzibar leopard, but we'll get to that later.)  In the meantime, let's look at what makes the Zanzibar leopard so special: its size.

When a population of animals becomes trapped on an island, they have to adapt or die: it's just that simple.  While many populations simply succumb to death, other populations of animals can sometimes shrink over the course of many generations, eventually becoming dwarfs of their former selves.  It's called island dwarfism, and it's happened many, many times throughout the history of life: the dwarf dinosaurs of Hațeg; the Channel Islands pygmy mammoth and the Channel Islands fox; the Cozumel Island fox and the Cozumel Island raccoon; and many, many others.  The subject of today's post is (you guessed it!) the Zanzibar leopard and, as you also might have already guessed, this particular leopard is an island dwarf!  

The leopard (Panthera pardus) is simply a fascinating animal.  Able to drag prey weighing more than three times its own weight in some cases, this mid-sized feline is the midnight stalker of the African savannah.  An occasional man-eater, there are numerous sub-species of the leopard, although no one can quite agree just how many there actually are.  While some people claim that there are just a few sub-species, others have claimed that there are around thirty!  However, most scientists agree that, at least for now, there are only eight or nine sub-species.  For regular readers of the blog, you've actually met a few of these sub-species already!  Probably the most famous, the African leopard (P. pardus pardus), was featured in a post about a year ago, entitled "Predators of Baby Leopards: You Might Be Surprised," in which we talked about....well, just read the post for yourself!  More recently, we met the Amur leopard (P. p. orientalis) in a post entitled "An Amur Leopard Upchucks."  I'm pretty sure you can figure out what that post is about all on your own.

There is some debate about whether the Zanzibar leopard is simply a separate population of the African leopard (P. p. pardus), or whether it is a distinct population defined by genetics.  When it is defined as a separate sub-species, the Zanzibar leopard has the scientific name of Panthera pardus adersi.  We'll talk more about this genetic confusion later: but that's enough about the genetics,  let's get to the interesting stuff!

Scientists think that the Zanzibar leopard has been isolated from the rest of the African leopard population on the mainland since the end of the last Ice Age, at which point global sea levels would have risen, cutting off the two main islands of the Zanzibar Archipelago, Unguja and Pemba, from the mainland.  Unguja, which is informally known as Zanzibar, is where the Zanzibar leopard can be found: at least, it used to be found there.

Remember when we were talking about how scientists can't really agree on whether the Zanzibar leopard is a distinct sub-species or not?  Well, their research is not aided by the fact that the Zanzibar leopard seems to be extinct.  Following the Zanzibar revolution in 1964, the government began a program to eradicate the Zanzibar leopard, both to stop apparent live-stock killings attributed to the cat, as well as to eliminate the leopard as an apparent source of witchcraft.  Research conducted in 1996 indicated that the leopard still survived on the island, but more recent research in 2002 has found no sign of the leopard.

Adapt or die: that's the mantra of the island animal.  When you throw humans into the mix, unfortunately its the second option that seems to occur most often.  Thousands of island animals have been exterminated by humans as their habitat is destroyed in the name of progress.  With nowhere else to go, they die out, leaving behind a legacy of destruction.

This was the birthday post of Ted Neher! Happy birthday, Grandpa! If you have a birthday coming up, just email me the date at with the date and your favorite animals, and I will do my best to get a post in! And if you like what you are reading, please feel free to follow us here or via Facebook!

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