Why do animals understand they need to incubate eggs?


I was watching this video recently (https://youtu.be/XAd1DlE7eaU) and in the first few minutes, he mentions something about the robin rotating the eggs under it so the heat distributes evenly. This make me really think.

How do these animals understand the incubation process? How can it understand something complex like knowing how often to rotate the eggs, or even comprehend it needs to rotate them in the first place? Does this suggest that knowledge is passed down through genetics?

In: Biology

It’s just pure instinct. They’re born with the urges to do natural things like find food, avoid predators, mate, and raise babies. If they don’t have that instinct, they’re much more likely to die, leaving those with the instinct surviving and passing along their genes. So pretty much natural selection for survival instinct

Yes, knowledge is passed down through genetics. All animals have some form of this knowledge, it’s called instinct. Humans do it too, we instinctively pay attention to and protect helpless small creates with large heads and eyes, because that’s what our young offspring looks like.
We’ve taken it a step further and created art (think about cartoon characters) with artificially large eyes and heads, that trigger this response. We’ve even bred some dogs to have large heads and eyes.

The thing about instinct is scientifically, it doesn’t really mean a whole lot. It basically boils down to we don’t know why. Like “instinct” better translates into reflexes, but they’re not quite the same thing.

Like we don’t have an innate knowledge to eat, we get hunger reflexes which hurt and are uncomfortable, pushing us to eat. Animals don’t just know what to eat and how to act, they are taught by their parents as a baby (with a couple of exceptions which we really don’t understand and are so far removed from us, we probably never will). Animals who are separated from birth need to be taught what to eat, and are typically very socially awkward within their species (ie in domestic cats, not knowing how to play or properly greet and communicate needs). Like there are biological responses (reflexes) involved in these things, like socializing gives you dopamine making you wanting to socialise more, but these are observable biological responses, not some force or knowledge that you’re born with.

I’m remember reading something about a flock of birds (can’t remember which ones) and most of the older birds died in a mass die off(that I can’t remember the context of) and because the younger ones weren’t yet taught how navigate the migration route, it was lost. It wasn’t instinctual, it was thousands and thousands of generations of teaching to retain the same migration route.

As with rotating eggs, there could be a reflex involved, or it could be a choice knowing that an egg always needs to be warm to hatch and just feeling the difference in temperature across the surface, or it’s something that chicks are taught before they leave the nest making it a cultural behavior, or a combination of these things.

You don’t know how you formulated this thought, but you did it without having to figure out how you were to formulate it.

Basically, you don’t need to understand something for you or your body to do it.

We do know some things are passed on through genetics (put an infant human in a standing position and it will start to instinctively walk) but it isn’t, to my knowledge, consistently understand what can be transmitted this way or how it works (for the record, I don’t know how much incubation is thought to be genetic vs. learned. It may vary per species).

Instinct is actually not a useful term in animal behaviour. It’s a catch all for any behaviour that doesn’t appear to be learned. Animals behaviour can develop and change over time based on their species typical experiences. Their predisposition to do that is, of course, genetically determined.

In the case of incubating eggs, this is a behaviour that has evolved for the same reasons anything does: because it increases the likelihood that genes will be passed on. Clearly that can’t happen if your eggs are not incubated!

What’s funny about this behaviour and many others is just how simple the underlying ‘urge’ is. The animal is not ‘thinking’ I better incubate my eggs to pass on my genes. They’re responding to their environment. Ethologists have shown that seagulls respond to the speckled pattern of their eggs with brooding behaviour. They painted bricks white with brown speckles and the seagulls sat on them for hours a day!

Why did this seemingly wasteful behaviour evolve? Because on balance sitting on an empty egg, or even a brick! Was a more successful strategy than more complex algorithms. Plus there weren’t any pesky naturalists replacing their eggs with bricks until quite recently!!