Have you ever noticed little holes in the skull of a buck?
QUESTION: Do you know what could have caused these holes in a buck skull? I don’t believe it’s from an abscess. – Justin Y.
ANSWER: The skulls of deer, and all mammals for that matter, have holes called foramena that allow structures like nerves and blood vessels to pass through. In deer, they’re typically around the base, eye sockets and nose. I must admit I had never noticed it before, but after reading your question, I went through a pile of skulls and racks and darned if every one didn’t have at least one tiny hole in the same location as your picture. Some even had several, which piqued my interest.
After an exhaustive search, I was unable to find anything specific on foramena in that specific location, so the rest of this is largely speculation.
Primitive species have a photosensory organ on top of their head called the parietal eye. It contains light-sensitive photoreceptor nerve cells that send signals to the brain. Deer have a small endocrine gland in their brain called the pineal gland. It receives signals from light-sensitive nerve cells, mostly in the retina, then uses these signals to regulate circadian (daily) cycles, telling the deer when to sleep and when to be active.
It may also influence seasonal cycles, like breeding behavior, which is in turn triggered by subtle changes in the amount of daylight. While it may simply be a vestige of days gone by, photo-sensitive cells in the forehead could also still function like the parietal eye in conveying light signals to the brain. — Recent Ask the Biologist Question:
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