Posted by Jude Chenier on October 23, 2007

Q: I have heard that the rings on horned mammals are used to age that animal such as the otolths of fish. I know that horn and antler development is stongly influenced by genetics and nutrition. Is this true, or are these rings a good estimate to the animals age. Thanks.

State: Louisiana

A: I had a little trouble on this one - I knew about antlers but had never questioned whether horns could be used to age an animal or not. Animals like the Bighorn Sheep, Mountain Goat, and Bison, have horns that never stop growing and do not drop off to be replaced. These horns exhibit periodic growth spurts that cause a ring-like pattern that can indeed be used to age the animal. Those animals with antlers, on the other hand, lose them yearly and their size and structure does not indicate the animal's age, as you noted. Hope this helps you out. Good question and one that helped me learn something new too.

John Wiessinger ( October 23, 2007)