Cottage Q&A: the science behind moose antler shape

Updated: October 4, 2018

A-young-bull-moose-in-Kananaskis-County-Alberta By BGSmith/Shutterstock

I saw a young bull moose in the morning mist last October. His antlers looked strange. Not only were they asymmetrical, they were not the usual palmate shape. Is this normal?

—Mike Beattie, North Bay, Ont.

Actually, asymmetrical and non-palmated antlers aren’t unusual on a yearling, says Vince Crichton, a wildlife biologist and moose expert in Winnipeg who has seen, he estimates, more than 30,000 moose and many, many pictures of antlers.

Antler size and shape is affected by diet, weather, habitat, and heredity, and it can vary by region, but they typically grow in one of two shapes: a palmate “shovel” shape and a “pole” shape, with long points or tines. In yearlings, you’ll see the early stages of one of these two. “Some have small palms, whereas others simply have a point,” says Crichton.

You likely saw a moose with one tine that was “not typical in terms of where it is pointed,” says Crichton. “This could be from an injury that occurred early in development and healed at the fracture point. Or it might just be a genetic anomaly.”

If it’s from an injury, next year’s set of antlers should grow normally. If it’s genetic, the two-year-old moose will grow a set of antlers with a similar structure. Either way, it’s all good. “He’ll be quite happy with his headgear,” says Crichton.

Truly abnormal antlers are “very, very obvious,” says Crichton. For example, moose who are castrated or sustain some other injury to the testicles—gah—will immediately shed their antlers, then grow a new, deformed pair.

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