Monday, September 28, 2015

Phantom of the Woodland Edge

For the last two years, I occasionally have seen a white-splotched female deer in my preserve.  This strikingly distinctive (and not very shy) doe frequents the meadows and a private fenced-in lawn just south of my organization’s headquarters. 

This doe is pied (or piebald), a condition that is relatively common among mammals, birds, and even reptiles.  A pied animal has irregular unpigmented patches of hair, feathers, or scales commingled with normally pigmented patches. The animal's skin is also unpigmented under the light patches and pigmented under the dark patches.  The piebald condition results from leucism, a genetic abnormality in which pigment cells fail to develop normally while the animal is an embryo.  If all of the animal’s pigment cells fail to develop normally, the animal will be completely white; if only some of the cells are defective, the animal will be piebald. 
Though the doe stands out because of her large white patches, she is not an albino.  In albinism, only the cells that produce the pigment melanin are defective whereas other pigment-producing cells continue to function normally, so albinos often have a pale yellow color created by other pigment-producing cells.

Another difference between albinism and leucism is eye color.  Albinos cannot produce melanin in their eyes, so they typically have red eyes because the underlying blood vessels show through.  In contrast, Pennypack’s piebald doe, like most piebald animals, has normally colored, dark eyes because the pigment producing cells in its eyes developed from different embryonic tissues than did its skin and fur cells.

The proportion of white to normal-colored skin on individual piebald animals can vary considerably between generations, between different offspring from the same parents, and even among members of the same litter.  Our piebald deer is a perfect example of this characteristic of leucism because our deer had two fawns in the spring of 2015, both of which were completely normal in coloration.
Incidentally, the terms pied and piebald entered the English language five centuries ago.  These terms referred to the magpie's black-and-white plumage combined with “bald” in an obsolete use meaning “streaked with white.”


robin andrea said...

Wow! Love seeing this leucistic deer at your preserve. It is always so interesting to be able to recognize an individual of a species, so that you are able to identify her year after year. It's great to see that she is producing offspring. I've only seen leucistic birds. It's pretty wild to see a deer like this. Very cool.

packrat said...

Awesome, Scott! Thanks for the enlightening post. And that photo is priceless. I love the expression on the piebald's face. :)

Scott said...

Robin Andrea: We've told our hunters to spare the piebald deer. Lots of visitors love to see her, so the hunters had better hold their fire. In the wild, of course, leucism would be a distinct disadvantage. But here in our carefully controlled preserve, her distinctiveness is an asset (I hope).

Scott said...

Packrat: The piebald deer is probably thinking, "Alright,'s time for you (two) to move on and let me get some rest."

Bob R said...

I captured my first photos of this piebald in August, 2013 and nicknamed her "Penny" (obviously!). I spotted Penny last week with her new telemetry necklace! She is a treasure for the Pennypack Preserve and along with our pair of Bald Eagles, hopefully teaching many people to respect and enjoy our special wildlife.