We get two local papers here, the Frontenac News and the Frontenac Gazette. An interesting thing about rural and small communities that you don’t really get in larger cities is these community papers. Of course, the larger cities have their own papers, too, they’re just serving more people so they lose that intimacy, that sense of community. Instead of hearing about local birthday parties or shop owners, or the front page photo being about the Superhero Spirit Day at the local high school, you’re hearing about various crimes and politics and the financial market. It’s much more interesting to read the little community papers.
Even so, I don’t always read them all, so when I was crumpling up a sheet from the News to get the fire started a couple mornings ago an article I hadn’t seen caught my eye, mostly because of the photo, which was of a deer. The headline read, “Local hunters fell unusual catch”. The full article is in the image above, but the gist of it was these hunters had killed a deer that had a single antler, which was in velvet. The deer, it turned out, was a female, a doe. A story about a female deer sporting an antler, won’t see that in the Toronto papers.
The story notes that the hunters called the Ministry of Natural Resources “with two understandable queries: 1. Is this a safe animal to eat? and 2. Would the MNR be interested in it?”
Those weren’t the questions that I was expecting. The two that had sprung immediately to my mind were: 1. Why does this occur? and 2. How common is it? The latter question had been answered in the article (although the hunters hadn’t known that upon killing the doe, I don’t think) based, I gather, on the MNR’s website. But the first question is not touched upon in the story. Really, that’s the most interesting part about it all, in my opinion.
So to finish off the story, why does this occur? And how common is it? Sources disagree on the answer to the latter question, with Wikipedia saying 1 in 10,000 will have one or both antlers, an article from Penn State U suggests 1 in 1,000, the Minnesota Department of Natural Resources suggests that it can vary from one population to the next, usually between 1 in 1,000 to 6,000. The same page also mentions one study in Pennsylvania found the occurrence to be 1 doe in 3,500 antlered deer (so, 3,499 males and one female), and another in Alberta counted 8 antlered does in 517 does total (about 1 in 64, thought to be the result of unusual genetics in the area, or perhaps just a sampling bias).
The explanation of why this happens lies in the physiology of the antler itself. It all begins with testosterone, the hormone produced primarily by the male testes, but which is also found in females (usually at about 1/20th the concentration it is in males). Deer have bony “buttons”, called pedicels, on the frontal bones of their skull. In the spring, a surge of testosterone triggered by increasing daylight levels prompts the pedicels to start developing bony growths. Initially they are soft, covered in blood vessels, nerves and fuzzy skin, referred to as velvet. In late summer a second surge of testosterone causes the bone to harden, the blood vessels to die back, and the velvet to slough off. The male deer rub their antlers against trees and branches to “polish” them, and remove the velvet, and then they use these hardened growths to spar with each other during the rutting season in fall. Early in winter, in the weeks surrounding Christmastime, the testosterone levels start to subside, and a layer forms between the antler and pedicel. Eventually the layer loosens enough that the antler is rubbed off and dropped. In the spring the cycle begins again.
In the case of these unusual does, some trigger such as a hormonal imbalance caused by first pregnancy, tumours, or degeneration or malformation of the reproductive organs or adrenal glands, releases that surge of testosterone that prompts the pedicels to start forming the soft velvet antlers. However, the doe never receives that second surge that results in the velvet sloughing off, or the subsiding of the hormone from this high level that causes the antler to fall off, so she ends up carrying a permanent velvet antler(s). Many such does are reproductively functional and can and do bear young, though others may have malformed reproductive organs. Some of these “does” may actually be hermaphrodites with the female organs dominant, or gyandromorphs (one half of the animal has XY chromosomes, the other XX – that is, one half is male, the other female, sometimes split nice and evenly down the middle like this Rose-breasted Grosbeak). “Does” with polished antlers, where the velvet has fallen off, are more likely hermaphrodites with the male parts emphasized, cryptorchids (males with undescended testicles, “crypto” is Greek for hidden, and “orchid” Greek for testicle), or pseudohermaphrodites that externally resemble females but internally are male.
So there you go, the rest of the story that was left out of the article (I figure they must have just run out of room on the page…).