Talk:Hibernation

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Misplaced information

Shouldn’t the Primates section be in aestivation?   User:Dunkleosteus77 |push to talk  04:43, 12 December 2018 (UTC)

Well, it sort of looks like that given the inadequate explanation, but it seems that a few primates like the Fat-tailed dwarf lemur do go into torpor, and that this is called "hibernation" by some scientists (including Dausmann et al and Faherty, refs already in article) even though the stimulus is drought rather than cold, so "aestivation" might be the more appropriate label. Perhaps the section needs quite a bit of rework and better sources, preferably a reliable review article.

Perhaps the real problem is that the definition of hibernation has changed in recent academic usage from one congruent with the word's etymology (wintering) to a more general one (torpor), while dictionaries, encyclopedias and the public have yet to catch up. The article ought to discuss the (history of the) concept of hibernation in a section near the top of the article (rather than having some scrappy cited discussion in the lead section, like a stub article) so the rest of the article can proceed on a secure footing. Chiswick Chap (talk) 08:17, 12 December 2018 (UTC)

Brown Fat: Brown adipose tissue is especially abundant in hibernating mammals?

https://en.wikipedia.org/wiki/Brown_adipose_tissue

"Brown adipose tissue is especially abundant in newborns and in hibernating mammals".

--ee1518 (talk) 14:34, 11 March 2019 (UTC)

Too much technical jargon, too many unexplained points, and too many irrelevancies in the opening section

The first paragraph runs:

Hibernation is a state of inactivity and metabolic depression in endotherms. Hibernation is a seasonal heterothermy characterized by low body-temperature, slow breathing and heart-rate, and low metabolic rate. It most commonly occurs during winter months.

"Endotherms"? "Heterothermy"? A definition that contains terms more unfamiliar than the term to be defined is not useful—the definition should use common English and enclose the technical terms between parentheses. And even though the term metabolism is familiar, just what metabolism is isn't common knowledge—people know that metabolism can be high or low, and that it's got something to do with digestion, weight, and energy, but "metabolic depression" and "low metabolic rate" are simply opaque. The only thing that laypeople know about the topic is that bears hibernate in the winter, so to say that it is a "seasonal heterothermy" is mystifying and to say that "it most commonly occurs during winter months" implies that it sometimes occurs in other months, but that contradicts the name and common knowledge. A revision might run:

Hibernation is a state of inactivity during winter months when in certain warm-blooded animals (or endotherms) the heart-rate and the rate of breathing slow, the body temperature drops, and the bodily processes by which energy is consumed and built up—metabolism—are also slowed.

The next paragraph is the first of two about the topic of what animals hibernate. It runs:

Although traditionally reserved for "deep" hibernators such as rodents, the term has been redefined to include animals such as bears and is now applied based on active metabolic suppression rather than any absolute decline in body temperature. Many experts believe that the processes of daily torpor and hibernation form a continuum and utilize similar mechanisms. The equivalent during the summer months is aestivation.

"Traditionally reserved"? Scientists don't have vague "traditions" that govern the application of a term, as for instance traditionally the term "America" applies only to the United States; instead, the referent of a scientific term is determined by theoretical criteria that admit of alteration. "'Deep' hibernators"? This term is not explained and, worse, because it is the bear that for laypeople counts as the animal that hibernates, it comes as a shock to hear that there was a time when scientists did not consider bears to hibernate at all. All in all, it is pointless to define hibernation using the modern criteria, and then to tell us that these were not always the criteria—that is not a statement about hibernation, but about the history of scientific understanding of the phenomenon, and it belongs in a history section. The statement about what experts believe is irrelevant—we want to know about hibernation, not about everything related to it—that info should be in a later section. The statement about aestivation is ill phrased, but should be retained while the rest of the paragraph should be cut.

Two paragraphs later, the other runs:

True hibernation is restricted to endotherms; ectotherms, by definition, cannot hibernate because they cannot actively down-regulate their body temperature or their metabolic rate. Still, many ectothermic animals undergo periods of dormancy which are sometimes confused with hibernation. Some reptile species are said to brumate, but possible similarities between brumation and hibernation are not firmly established. Many insects, such as the wasp Polistes exclamans, exhibit periods of dormancy which have often been referred to as hibernation, despite their ectothermy. Botanists can use the term "seed hibernation" to refer to a form of seed dormancy.

"Endotherms," "ectotherms," "down-regulate," "brumate," "polistes exclamans"—the author or authors of this paragraph really want to establish their scientific chops, don't they? Again, an encyclopedia article or passage thereof not written in ordinary English is useless.

"True hibernation"? If what other living beings do is not hibernation, then there is no point in mentioning them. Hibernation may be a type of dormancy, but if that is so, then there should be a simple statement of that fact. On the other hand, if what ectotherms do is confused with hibernation, meaning that what they do is not hibernation, and if some reptiles are just "said" to brumate, but the similarities have not been "firmly established," and if again insects are ectotherms, and their periods of dormancy aren't really hibernation but are "referred to" as hibernation, as botanists "refer to" seed dormancy as "seed hibernation," then with each statement one has given a reason not to mention any of these things because they have nothing to do with hibernation. The entire paragraph should be cut.

The third paragraph runs:

(1) Hibernation functions to conserve energy when sufficient food is unavailable. (2) To achieve this energy saving, an endothermic animal decreases its metabolic rate and thereby its body temperature. (3) Hibernation may last days, weeks, or months - depending on the species, ambient temperature, time of year, and the individual's body-condition. (4) Before entering hibernation, animals need to store enough energy to last through the duration of their dormant period, possibly as long as an entire winter. (5) Larger species become hyperphagic, eating a large amount of food and storing the energy in fat deposits. (6) In many small species, food caching replaces eating and becoming fat.

There are four themes in this paragraph: what hibernation does (1); what animals do to make hibernation function as it does (2); how long hibernation lasts (3); and what animals do before they hibernate (4-6). But surely it is wrong to represent an animal as decreasing its metabolic rate—that's just what happens when the animal falls asleep, or whatever the process is by which it enters into the specific inactivity of hibernation. More importantly, the lowered temperature and the slowed metabolism aren't different from the conservation of energy, but simply the way in which energy is conserved. Since this is information about the central phenomenon itself, it should be included in the opening paragraph, which would then run so:

Hibernation is a state of inactivity during winter months when in certain warm-blooded animals (or endotherms) the heart-rate and the rate of breathing slow, the body temperature drops, and the bodily processes by which energy is consumed and built up—metabolism—are also slowed. The lower breathing, heartbeat, temperature, and slowed metabolism function to conserve energy when sufficient food to maintain the normal metabolic rhythms is not available. Hence before entering into the metabolically depressed state, large animals eat more food than usual and store it as fat (hyperphagy), whereas many small species, instead of eating to deposit fat, store food in caches. Either way, the fat deposits and the caches must contain enough food to last for the entirety of the dormant period. Depending on the species, the individual's bodily condition, and the ambient temperature, that period can last days, weeks, months, or an entire winter. When the phenomenon of metabolic depression occurs in animals during the summer months, it is called aestivation.

The fourth paragraph runs:

Some species of mammals hibernate while gestating young, which are born either while the mother hibernates or shortly afterwards. For example, female polar-bears go into hibernation during the cold winter months in order to give birth to their offspring. The pregnant mothers significantly increase their body mass prior to hibernation, and this increase is further reflected in the weight of the offspring. The fat accumulation enables them to provide a sufficiently warm and nurturing environment for their newborns. During hibernation, they subsequently lose 15–27% of their pre-hibernation weight by using their stored fats for energy.

Another thematically disordered paragraph. The central theme seems to be the importance of the mother's body fat; the muddle occurs in the vague claim that with the fat the mother provides "a sufficiently warm and nurturing environment," in the claim that the mothers lose fat, and in the claim that the increase in body fat is reflected in the weight of the offspring rather than the loss of weight. The paragraph should run:

The females of hibernating species, like the female polar bear, gestate and sometimes give birth to their offspring during the inactive period. They therefore also eat to accumulate the extra body fat necessary for the offspring to be born fat themselves, reflected in the fact that mothers lose between 15 to 27% of the extra weight they gained, and also to make sure that the offspring can keep warm.

Thus the revised section would read:

Hibernation is a state of inactivity during winter months when in certain warm-blooded animals (or endotherms) the heart-rate and the rate of breathing slow, the body temperature drops, and the bodily processes by which energy is consumed and built up—metabolism—are also slowed. The lower breathing, heartbeat, temperature, and slowed metabolism function to conserve energy when sufficient food to maintain the normal metabolic rhythms is not available. Hence before entering into the metabolically depressed state, large animals eat more food than usual and store it as fat (hyperphagy), whereas many small species, instead of eating to deposit fat, store food in caches. Either way, the fat deposits and the caches must contain enough food to last for the entirety of the dormant period. Depending on the species, the individual's bodily condition, and the ambient temperature, that period can last days, weeks, months, or the entire winter. When the phenomenon of metabolic depression occurs in animals during the summer months, it is called aestivation.

The females of hibernating species, like the female polar bear, gestate and sometimes give birth to their offspring during the inactive period. The mothers-to-be therefore also eat to accumulate the extra body fat necessary for the offspring to be born fat themselves, reflected in the fact that mothers lose between 15 to 27% of the extra weight they gained, and also to make sure that, no matter how early in the mother's hibernation they will have been born, the offspring can keep warm.

The virtues of this revision? It is clearly focused and concise: what needs to be said is said once and in the fewest possible words, and nothing is said but what a reader needs to have a creditable understanding of the phenomenon if they read no further. That's the function of the opening section of an encyclopedia article.

As it now stands, the section is a mystifying blend of technobabble and not just irrelevant but downright contradictory statements. Its faults reflect the fact that the authors are not concerned with informing the lay reader, as they should be, but rather with showing that they are familiar with the technical aspects of the matter and with debates in the technical literature. In other words, I am sorry to say, they are showing off.

Since I am no expert, I cannot know whether I have included all of what counts as the minimal amount of information a layperson needs to have a solid grasp of the bare essentials of the phenomenon—I would really like to know, for instance, how animals actually get into the state: Do they curl up and go to sleep? Is sleep then a threshold state at which point some sort of seasonal "clock" at work in a system that regulates metabolism transforms the sleep into the state of hibernation?

I do know, however, that no layperson who reads my version will stumble over jargon or get lost in irrelevancies. Nevertheless, I make no claim that my "reader-friendly" version is the friendliest possible, so of course I welcome anatomies of my own oversights. Wordwright (talk) 02:11, 5 May 2020 (UTC)

Origin?

One would like to know if it is a family trait or if hibernation is widely distributed between different groups of animal species? When did the phenomenon first appear, etc. Zzalpha (talk) 06:41, 12 February 2023 (UTC)