Deer, Elk, Moose (?) Grow and then shed antlers each year. Each successive year the animal grows a more impressive rack. No hard and fast rule, but about one additional tine on each side per year.
What is the mechanism that causes the antlers to re-grow larger with more forks each time? Or put another way, how do the antlers “remember” how they grew last year, and thus “know” to grow bigger this year?
I had always figured it was the biology getting better at what it was doing with each round. Like how the initial months of menstruation in women are often irregularly timed but get more predictable each cycle (on average, obviously). Or how your immune system gets better at responding to a given pathogen each time you are exposed. By my thinking, there are more quiescent cells needed for whatever it is your body is trying to do, hanging out, waiting for the hormones to kick things over again. Tissue memory.
Thanks Pullet…guess I’m sort of asking whats behind tissue memory.
Also:
Is there nothing they can’t find an ad related to?
The reason is still unknown. Antlers come from stem cells in the pedicle from which the antlers grow. The pedicles get larger as the animal ages, presumably that is a factor.
IIRC, antler growth is also influenced by sex hormones. These levels fluctuate according to the season and the age of the animal. Suppose that testosterone production ramps up in the months prior to the breeding season, and peaks during the breeding season. That peak probably increases as the animal ages, so a 3-year-old animal will have more hormonally-influenced antler development than a yearling, and less hormonally-influenced development than a 5-year-old animal.
That’s definitely the case and is a factor in the overall antler size. Perhaps some kind of fluxuation or pulsing in the testosterone levels during the antler growth phase contributes to branching. Say if the fluxuation was a percentage of the total level and there was a minimum amount required to generate a branch.