Friday, January 17, 2014

Maryland: Weird and Wonderful - Piebald Deer

"Maryland: Weird and Wonderful" is a WMD101 series showcasing specific natural phenomena occurring in Maryland that are particularly interesting or unusual. 


Between the brown trunks and dappled shadows of trees, a ghostly white shape steps quietly.  Its snowy coat and delicate movements are reminiscent of a heraldic unicorn. But this striking animal is no mythical creature - it's a piebald white-tailed deer!

A piebald white-tailed deer with normally-pigmented companions.
Image public domain by the U. S. Fish and Wildlife Service via Wikimedia Commons.
White-tailed deer are normally brown in color, with white on their throats, undersides, insides of their legs, and of course, under their tails.  They vary their color by season, being gray-brown in the winter and red-brown in the summer.

Piebald deer, however, have a genetic mutation that causes pigmentless, white patches throughout their coat. The skin beneath these patches is also pigmentless, appearing pink. The effect is similar to white spotting patterns in horses or rabbits.

Piebald is a broad "catch-all" term for animals with unusual pigmentless patches on their bodies. It is also known as "white-spotting," "pied," "partial-leucism," "partial-albinism," or "part-colored."

Because "piebald" describes only the appearance of an animal, but not the specific underlying condition, the cause of piebaldism varies greatly by species and within species. Piebald coloration can be caused by genetic mutations, developmental abnormalities, injury, disease, and even nutritional deficiencies. Horses, for instance, display over five different forms of piebaldism, all under the influence of different genetic and developmental mechanisms.

A piebald deer sighted in VA. Image public domain via Wikimedia Commons
While piebaldism may at first seem like random white spattering, the pigmentless areas actually follow a pattern, with some areas of the body more likely to be white than others.  Below is a rough chart showing three types of piebaldism in deer and their patterns.  These different types of piebaldism are likely the result of different genetic mutations.

A chart showing three patterns of piebaldism in white-tailed deer.
Many wild piebald deer show the Type 1 pattern, whereas many piebald deer bred on deer farms show the Type 3 pattern.
Image copyright Jane Marlow. 
Piebaldism in deer is commonly thought to be the product of a recessive gene or genes. Because recessive genetic traits are more likely to physically appear when inbreeding occurs, piebald deer may be more likely to occur in inbred or isolated deer populations, such as those in habitats surrounded by a tall fence or by urban development.  Piebald deer are also credited as being more likely to show other unusual traits, such as unusually curved spines and short legs, than normally-pigmented deer.

Piebald deer have been sighted throughout Maryland, even in Baltimore City!  While Maryland's DNR website states that around 1% of deer are piebald, this percentage may be higher in local or isolated populations.

Two piebald deer. Image public domain by the U.S. Fish and Wildlife Service via Wikimedia Commons.
Piebaldism is generally seen as a disadvantage for many wild animals. It can interfere with the camouflage of both predators and prey, and can make prey animals more easily targeted in a group.  Because the skin under the white fur or feathers of piebald animals lacks pigment, it has limited protection against UV rays and can be prone to sunburn.  Further, piebaldism is sometimes linked to other traits that lower physical fitness, such as the curved spines seen in many piebald deer.  Under natural circumstances, it is likely that piebald animals do not survive or reproduce as well as their normally-pigmented brethren, making them more rare.

Despite the disadvantages of piebaldism that may occur in the wild, humans have long considered piebaldism an aesthetically appealing trait and have selected for it in domestic animals.  The vast majority of domesticated species are commonly found in piebald patterns, including cows, goats, sheep, horses, dogs, cats, pigs, alpacas, ferrets, chickens, ducks, pigeons, finches, and even domestic parrots, such as cockatiels.

Ancient Egyptian art depicting domesticated cattle with piebald patterns.
Image public domain via Wikimedia Commons.
Piebaldism has also been spotted in several other wild animals in Maryland, including American robins, dark-eyed juncos, and gray squirrels.

So next time you see a flash of white among the shadowy hues of the forest, look closely!  You may catch a glimpse of a rare piebald animal!

REFERENCES:

Diseases and Parasites of White-tailed Deer: Piebald Anomaly. Maryland Department of Natural Resources. Web. 17 Jan. 2014. <http://www.dnr.state.md.us/wildlife/Hunt_Trap/deer/disease/ddpbald.asp>.

9 comments:

  1. I saw one 7 or 8 years ago on Fieldcrest Rd, Laytonsville, MD. To this day people don't believe me!

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  2. I saw a piebald fawn with its dam today, 14 August 2014, on Fort Meade. Took several photos. Way Cool!!

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  3. I've seen plenty of these beautiful deer in the Odenton/ Ft. Meade area. But the best part is on my property i get to watch a little piebald fawn grow. Shes grown up so much this year and got to see her in person while in the woods one day. Shes beautiful.

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  4. Saw a type 1 in whitest configuration grazing roadside along 193 in Glenn Dale in PG County. Looked like a doggone Dalmation! Stunning. Wow.

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  5. There's a piebald deer in Columbia MD

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  6. I just saw 7 of them along the road on I40 east bound New Mexico on March 25 2016...... they were just eating in a group and they are beautiful.... love the little white fluffy tail

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  7. We have two or three in east t.n. They are very beautiful they love apples

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  8. We have two or three in east t.n. They are very beautiful they love apples

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  9. I saw on that was entirely white on Rt 179 near Old Mill Bottom rd. in Arnold. She was standing in the middle of the road. I drove up to her and she looked at me as if to say ~what up? Then she casually strolled off the road. She was entirely white with a patch of black around one eye,

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