Many animals that live in seasonal zones have lifecycles that are adapted to the changing of the seasons. What happens to these animals if you ship them from the northern to the southern hemisphere (or vice versa) where the seasons are reversed? Let’s take a North American squirrel that normally is active in the summer months and hibernates in the winter and ship it to a zoo in Australia in October. The squirrel has been active for about six months and would normally be getting ready to go into hibernation. But Spring is just arriving in Australia in October and winter is still six months away. How does this affect the squirrel? Is he going to follow his inherent schedule and hibernate through the Australian summer and wake up just in time for winter? Does he adapt in just a few weeks or is his life cycle permanently off kilter? Do places like zoos have to acclimate animals to their new seasons?
Don’t know about squirrels. But I do know about Mink moved to Argentina. The reproductive cycle in Mink, as in many animals, is governed/triggered by the increase in daylight hours in the spring. The breeding Mink moved to Argentina in our fall or winter months (can’t recall exactly) did not come into season in March of the following year but waited until September. Their furring cycle is governed by the decrease in daylight hours in the fall, and Mink grown in the Southern Hemisphere are in prime in our spring. I don’t know if the mink farm in Argentina is still in business, and I can’t say I know of any other in the southern hemisphere, but there could be some.
Many animals that hibernate do so only (or more so) in the colder end of their range, and just won’t hibernate if the conditions don’t provoke it - with a few exceptions, I think most species would adjust quite quickly.
Plus of course, cats will circle in the opposite direction before going to sleep.
Animals don’t care about the calendar, their bodies react according to length of day, temperature, and ease of procuring food.
Fido hated the crossing-the-line ceremony, but he dug being a shellback when it was all over.
The horse industry takes advantage of the fact that the mare begins to cycle when the day lengthens. Stallions are used in North America in the winter/spring months when mares in the US are in heat, then shipped down to the southern hemisphere - Venezuela or Argentina - to breed mares during their fertile time in August - December.
I understand that animals have no idea what month it is. My question was how it affected their bodies to suddenly have a summer (or winter) that effectively lasts twelve months long.
That’s my point, they don’t care–their body only makes seasonal shifts when the environmental signals tell them to. In a particularly warm winter, for instance, hibernating critters may not hibernate at all.
I’m not sure it can be universally true that they don’t care - is there not also an internal clock in some cases? (in the same way that there is for day and night cycles - that gets upset if a day lasts longer than it should- i.e. jet lag)
Well, maybe they suffer deep emotional distress over it, but it’s still true that if the winter is balmy and there’s plenty of food available, they’re not going to go down for a three-month nap.
It was sun-shiny and warm in LA this December and a friend’s fig tree was starting to fruit, despite February’s likely frost. Since I’ve moved to Oregon, my snakes don’t brumate through the winter, though they do get sluggish and only act interested in food about once a month. This last winter was pretty warm, except for a two-week cold snap. In that two weeks, my dog suddenly developed spots and a heavy undercoat. Plants and critters don’t have any way to judge the calendar weeks or months. They just go by what the weather tells them to do.
Another thing–we manipulate this with breeding animals all the time. If you want to bring a mare into season, you change the lighting in their stall. If we want to cause a colony of mice to breed like bunnies, we change the light cycle in the room, and so on.
Sure - I was thinking maybe they might experience disturbances of mating cycles, season-specific behaviours, plus weirdness from biological processes (coat changes, body fat storage, etc) that are mid-way through their cycle and are suddenly no longer appropriate, or upsets from the fact that other processes should (by local trigger conditions) be underway, but are not yet started.
Well, they will halt mid-process if the season tells them to, and likewise will cycle very quickly when the need arises. See also: my dog’s instant winter coat during the brief freeze. If you took an animal in full winter coat across the equator and dropped them in the tropics, they’d blow that coat very quickly. Critters are adaptable, they do what environmental signals them to do, because doing so helps them survive. As far as season-specific behaviors and the rest goes, if it’s suddenly warm and sunny and there’s food about, they don’t know it’s December. Whether or not they’re “bothered” by it, I can’t say.
That seems to assume that the processes are provoked by the prevailing conditions of the moment. Is that really the case? Are none of them based on cascades of events and changes?
Sure they are. In a typical change of seasons, biological processes have some time to “warm up”–as days grow shorter, animals may cache food, prepare dens, build a layer of winter fat, develop a heavy coat of fur possibly of a different color, and so on… but that’s not what the OP is asking. The OP asked “what happens when a sudden and unexpected change of seasons occurs?”
In a winter wherein there’s a brief respite of a couple warm and sunny days, a hibernating squirrel won’t suddenly wake up, blow coat, and look for a mate. However, if you transported that animal across the equator and dropped them in a place where there are no environmental indicators that there’s a benefit to staying in a state of hibernation then… he won’t hibernate. Likewise, if you take a dog in summer coat to the arctic, they’ll develop a warm undercoat very quickly. In a normal situation, these are gradual changes triggered by gradually changing seasons, but in an abnormal situation, they can and do adapt very quickly.
To clarify, in that first case, your cascade of events that trigger preparations for winter would be hours of daylight growing shorter, temperatures gradually dropping, food growing more scarce, and so on.
I disagree - I think it’s exactly what the OP is asking - whethe the processes of seasonal adaptation will attempt to grind on mechanically, prejudiced by some previous state, or if the organism can quickly snap out of them.
No. I’m asking about a cascade of internal processes, not external stimuli. The progress of seasons is not a cascade, it’s a sequence.
No, they won’t.
Yes, they can.
This is not, of course, 100% true. Some animals such as rabbits, triggered into an early mating season, can re-aborb embryos if conditions are not well for gestation and birth. Others, as any shepherd facing a winter crop of lambs can attest, will carry on regardless.
Generally speaking, though, I’ll stick by what I said. Faced with an unexpected shift of seasons, an animal doesn’t care whether the summer is five months long or ten months. They won’t spring into “winter mode” if they’re in Australia, simply because the calendar says it’s December.