Moose with Sleigh Hoof? Seriously?

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Moose sightings in Alaska are nothing unusual. These large animals are frequently seen about various towns, popping up in backyards and being seen crossing roadways. In fact, it was a recent roadway sighting on Elmore Road in Anchorage, Alaska that is drawing attention to the moose for a surprising reason: the condition of the animal’s hoofs.
 
Animals with hooves are generally able to wear them down to a comfortable level by simply moving about. Though we have domesticated horses and cattle to sometimes need human assistance to keep hooves trimmed to a managable level, the moose is not an animal that tends to have such problems, at least not under normal circumstances. One moose in particular, however, cannot boast those normal circumstances and instead is plagued by a condition known as sleigh hoof.
 
What is sleigh hoof and why does it occur? The root cause of this interesting sight is a copper deficiency within the body of the moose. Whereas a normal hoof would grow at a pace that allows natural wear and tear to keep it scaled back to a functional level, a copper deficiency has the opposite effect. Instead of hooves growing at a normal rate, the growth rate is accelerated immensely. The end result is hooves that cannot be worn off fast enough to compensate for their rapid growth. Afflicted hooves then take on a strange appearance in that they actually curve upward much like the skids of a sleigh, hence them being referred to by the term sleigh hoof.
 
The condition known as sleigh hoof is not common but is sometimes seen around Southcentral Alaska in Anchorage and the Kenai Penninsula. The reason it is seen in this area is due to below average amounts of copper in the ground as well as foods generally consumed by moose and typically a couple of cases are noticed on an annual basis. Though this deficiency exists, it is thought that the moose in the area remain largely unaffected because their bodies have acclimated to the reduced copper, making them more efficient at processing what little they do get and therefore allowing most to develop a normal hoof.
 
Although sleigh hoof is most commonly associated with a copper deficiency, there could be other causes as well such as inflammatory disease or an overabundance of other minerals. For example, a diet too rich in iron or zinc can inhibit the moose’s ability to absorb copper. Another potential cause of hoof deformity could be laminitis which leads to the formation of larger hooves in ungulates.
 
What does all of this mean for big game hunters? For starters, conditions such as a copper deficiency can negatively impact the moose’s reproductive system, causing a decline in birth rate. With fewer moose being born, fewer moose will in turn be available for hunting. It is also possible that affected moose will contract parasitic infections due to the negative toll copper deficiency takes on the autoimmune system.
 
Ideally sleigh hoofs will eventually break off, returning the moose to a normal, comfortable state of movement. However, hooves that remain intact could inhibit the moose’s movement and put the animal at a higher risk of injury or even death. Although animals can and probably do acclimate to this condition, it is very possible that the cumbersome nature of it may make their movements more labored and impair their traction.

In scenarios such as this, it is possible that predators will get to the moose long before the big game hunter does, maintaining the status of sleigh hoof and affected moose as an elusive sight.