Tuesday, June 14, 2011

Odd Odocoileus

This sorry fellow showed up yesterday.  He has a deformed antler, still in velvet, that makes him appear a bit like a flop-eared dog.

I originally assumed that he may have broken the antler mid-growth.  Maybe trying to spar a little to soon?  Or possibly a car accident?  But after chatting with a biologist/deer hunter (thanks Vic) and a quick peruse of Google, it turns out that there are many possible alternative causes for deformed antlers, ranging from damaged testicles to "trophic memory" of old injuries, and many are not immediately intuitive.

One of the most interesting I found is that injury to a rear leg may cause reoccurring abnormal development of the antler on the opposite side!  Last year there was a young deer with an injury on a rear leg, but I didn't think to get any photographs or record the date or side of the injury.  It would be fascinating if it is the same deer.  However, the drawings of those deformed antler deer don't show it looking quite as broken as this one does.  

An article from the Mule Deer Foundation points out some really interesting side notes"Besides direct trauma to the growing antler, injuries to a large skeletal structure such as a broken leg bone often causes a misshapen rack the next antler cycle. If the front leg is injured, either side of the rack may be affected. However, if the rear leg is injured the opposite side of the rack is usually misshapen." I originally thought that I may be able to figure out if it was trauma to the antler directly if it grew normal next year, but then I read "If one pedicle is injured severely, that side or both sides will be malformed during the next antler cycle. In addition, the nerves may “remember” the injury and reproduce nontypical antlers for several years. This “trophic memory” only occurs when the injury is substantial and occurs in the early stages of antler growth when there is a high density of nerve connections in the growing antler tissue. "

There are many interesting anecdotes about what may cause malformed antlers, but nothing conclusive about this particular situation.  However, it appears to most closely resemble the following description "If an antler tine breaks completely while still in the velvet phase it may stay attached to the rack via the velvet skin and re-fuse with it leaving a pendulous (hanging) tine that usually has a large rounded tip."

This deer is a regular here.  He travels with a companion who has distinctive ear injuries, so I can at least confirm the companion is the same individual.  Here is an image of both of them, taken one month earlier.  I hadn't noticed at the time, but in this image, the Odd Odocoileus (on the left) appears to have a smaller antler starting on the side that is very deformed now.  But it may just be the angle of the photo.



Does anyone have any additional thoughts on this?

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References and Additional Information:

  • Stable URL: http://www.jwildlifedis.org/cgi/reprint/8/4/311.pdf
  • Stable URL: http://www.jstor.org/stable/1376120 - 1959. W. Leslie Robinette and Dale A. Jones. Antler Anomalies of Mule Deer. Journal of Mammalogy Vol. 40, No. 1 (Feb., 1959), pp. 96-108 
  • http://www.muledeer.org/news/magazine_articles/2009/JulAug09_NotYourTypicalAntlers.html


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