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Thursday, April 05, 2012

Telling Nannies and Billies Apart

The last 2 days I have been skate skiing back up to the big ravine at the headwaters of the Buskin River. We have a lot of snow and there is a solid crust for skate skiing. There is a herd of mountain goats in the ravine and it has been fun to check them over and see if I can tell the difference between the nannies and the billies. This is not an easy task. By looking at the photos above can you tell the difference? The nanny and kid are pretty obvious but what sex are the 2 goats in the top photo?

For a couple of years I did a lot of bow-hunting for mountain goats. When you bow hunt you get up close and personal to the goats quite often, and I got pretty good at telling the difference between the nannies and the billies. generally the big billies are bigger and off by themselves with a dirt-stained back end (in the fall), but you can also tell the difference between them by their horns. Billy goat horns are much fatter along their length and curve evenly the whole length while nanny goat horns are thin and sort of flare with a bend near the end. I look at how fat the base of the horns are in relation to their eyes - fatter than the eye and it is probably a billy, thinner and it is probably a nanny. Also billies seem to have almost no space between the horns at the bottom and you can often see a black gland around the bases.

Anyway, in the top photo, at first I thought both were billies, but on inspection I think the top one is a billy and the bottom one a nanny. But I am not sure! What do you think?

For more information on how to tell the difference check out the Alaska Department of Fish and Game website:

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