In all honesty, I don’t think anyone was under the impression that it was the actual calendar that made a difference.
That’s pretty much it. I figured there must be some internal schedule to complement the external stimuli. An animal would be able to adapt to the difference between a twelve week long winter and a sixteen week long winter with no problem. But I was wondering if a thirty week long winter might be beyond any genetic back-up plan and put the animal’s metabolism at a loss for what it should be doing.
What’s the difference? I’ll say it again. They don’t care what month it is or how many months have gone by. They just do what gives them the best chance of survival, based on prevailing environmental conditions.
The point I’m trying to pick at though, is that environmental conditions are not the only things that prevail.
Let me put it another way, based on your last question. If you keep in captivity an animal from an environment that differs significantly from the one you live in, and you want it to follow normal biological rhythms, you have to provide it with the environment that triggers those changes.
For example, herpetologists that want large, healthy clutches of eggs will brumate their cornsnakes by simulating a winter cycle in their natural environment. You feed them heavily for a couple months, fast them for a couple weeks, then keep them in the dark with no food at fifty to fifty-five degrees for approximately ninety days. When the ninety days is about up, you gradually expose them to shorter, then longer periods of light starting with an hour a day. You also gradually turn up the temperature. After a week or so, you start feeding them again. In a couple weeks she’ll shed her skin and she’s ready to boogie.
I have never wanted to breed my cornsnakes, so have never purposely initiated this sequence. When I lived in an area where there were distinct seasons, they would brumate themselves as they saw fit. Now that I live in an environment where there are no distinct seasons, they don’t brumate. They just chug along, maybe becoming a bit less active and eating less when they’re burning fewer calories. I do have “mating pairs” of snakes, and they do not mate without those specific environmental triggers.
Maybe there’s something I’m not getting. Can you provide me with specific examples wherein an animal will act like it’s winter, when there are no environmental conditions to tell it that it’s winter?
There must be
I’m not specifically talking about acting like it’s winter when it’s not, I’m talking about physiological changes that may happen as the result of previous ones being set in motion - in a cascade, ultimately triggered by some environmental stimulus at some point in the past, rather than happening because of immediate stimulus now.
I don’t have any specific examples, because this is a query, not an assertion. But it just seems too simplistic to say that in every case, they will stop doing what they were doing and start doing something appropriate to the immediate environmental stimuli. What about processes set in motion, but incomplete? What about other processes that would be set in motion by the completion of the previous?
Antler formation, for example - deer start growing antlers before the mating season and shed them afterward - presumably the start of growth has some environmental trigger, but they don’t just spring into existence fully-formed - they have to develop - will this process halt if the animal is moved to the opposite hemisphere? Or will it continue to completion - and if so, when it completes, will the animal then find itself in mating mode, or will it just shed them?
Of course it’s overly simplistic to say that in every single case X will be true, and of course I’m not going to have cites for every single seasonal biological process and behavioral pattern of every species of animal, but, in general… animals will behave as the overriding environmental patterns “tell” them to. The change may not be immediate–behaviors such as waking from hibernation may be, but physical changes like a snowshoe hare’s white coat changing to mottled then brown obviously take some time. I’m not sure how many ways I have to say that, or how many examples need to be given.
In the case of antlers, their growth is triggered by specific photoperiods and accompanying hormonal changes, as is their shedding. In controlled environments, buck deer can be triggered to grow and shed up to three sets of antlers in a year, and can retain the same set for more than a full year. If you transported an antlered buck to a post-rut environment, he’d shed the antlers. If you put him in an environment where conditions appeared as in the rut, he’d retain them until triggered to shed them. Regarding your last question, it’s not the presence of the antlers that puts them into rut, it’s… wait for it… the season. 
If the opposite is true, and antler growth process is interrupted due to a drop in testosterone (such as injury to a testicle) but with environmental conditions continuing to stimulate antler growth, the antlers will grow but remain in velvet. So, while the season triggers the growth, hormones (triggered by the season) also have some effect. If you remove the environmental stimuli, the process is either entirely abbreviated or suspended, based on the new conditions.
So, sure I’ll concede that some processes might take a bit of time to shift gears, and some–such as gestation–may not be able to be interrupted in all species, but in general, animals will adapt to whatever behavior is most biologically successful for them based on the prevailing conditions. Transported to wildly inappropriate environments, of course, all bets are off.
I should add that I’m totally happy to accept examples that run counter to what I’m saying, if anyone has them. I just can’t come up with any, myself.