Possible for Zebra to know foal is not his?

[cochrane]

@Ignotus

Actually, it would be a case of the green-beard effect. I don’t know if there are other known examples among mammals.

In the cause of fighting ignorance, it would be great if users defined their terms. Or at least gave a link to further reading.

Green-beard effect.

[Ignotus]

Sorry; as a Dawkins fan I assumed the term to be common knowledge, much like “meme”. My fault.

[cochrane]

@Ignotus

Sorry; as a Dawkins fan I assumed the term to be common knowledge, much like “meme”. My fault.

I apologize if I came across as being snarky, but I never heard of the green-beard effect and have no idea who Dawkins is. I didn’t mean to sound so rude.

[jimbuff314]

Richard Dawkins.

Tee-hee.

[Ignotus]

I apologize if I came across as being snarky, but I never heard of the green-beard effect and have no idea who Dawkins is. I didn’t mean to sound so rude.

Hey , I’m not even British, and I don’t want to indulge in any “Beggin’ your pardon” exchange! Fair said, fair accepted!

But you should read Dawkins. Really.

[Jackmannii]

@Shakester

So, perhaps the trigger is “potential rival” and not “not my descendant”.

And maybe also “get the female to stop paying attention to the foal and focus back on me”.

[Stoid]

@Jackmannii

And maybe also “get the female to stop paying attention to the foal and focus back on me”.

:dubious:

[Lucas_Jackson]

@Earl_Snake-Hips_Tucker

The video in question. The relevant part is at about 43:20.

Wow, what a dick that yikes is.

[Smeghead]

@Habeed

How it could tell is simple. There’s a variety of genes in the zebra that code for proteins that are emitted in a vapour cloud from the animal. (usually called pheromones)

If the Zebra male is the daddy, a certain unique combination (essentially just a particular combination of possible genetic fragments, like the digits in a binary number) of alleles will compose half the genes for the proteins used for pheromones.

Inside the Zebra’s nose, there’s these special cells with pseudorandom chemoreceptors that each respond to different possible molecules.

The Zebra knows his own smell, so he knows what “his” combination of pheromone signals smells like.

Animals are not thought to use past memory the way humans do, they are thought to mostly live in the present. So instead of thinking to itself “that little bitch” when the male Zebra doesn’t smell himself on the baby zebra, the algorithm is more like :

Run_Continually : If (Baby_Zebra && Smell != 0.5 * Self_Smell) Kill_Baby();

Unlike serial programming, my statement of pseudocode above is executed in parallel with all other systems in the Zebra’s brain : essentially there’s a group of neurons in there that are perpetually waiting for the pattern of a baby zebra that doesn’t match the zebra males, and will trigger when that happens.

On the bright side, the male zebra probably does not feel any guilt for his actions after it happened. A day later, he doesn’t remember he did it. The female zebra probably doesn’t remember either, though she probably feels animosity towards the male zebra for reasons she does not remember.

This is pure speculation.

[Fubaya]

This says:

Courtship, Receptivity and Mating

The female’s estrus cycle lasts about five days, during which, they are receptive to mating for about two or three days. When ready to mate, the female arches her back, raises her hindquarters and moves her tail to the side.
…
[horse romance ensues]

So, they quit mating once they’re pregnant. He’ll never be able to mate with her until after she gives birth, and once she gives birth, it obviously isn’t his. All he has to do is remember which females he’s gotten lucky with.

He could probably also tell whether a female is pregnant through her pheremones and put “kill her kid” on his to do list.

Animals are smarter than we give them credit for.

[Carryon]

I grew up on a farm, and my own experience is people often back explain things to suit them. I would bet the Zebra has no real idea who is or who is not his foal and just killed it. It’s really very little biological expense for him to mate again, so if he kills one of his own, it’s not that big a deal to him.

And one thing I learned being raised amongst animals is simply some animals can be jerks.

Not whole species, but like some humans some animals are simply jerks.

[Earl_Snake-Hips_Tucker]

@Carryon

I grew up on a farm, and my own experience is people often back explain things to suit them. I would bet the Zebra has no real idea who is or who is not his foal and just killed it. . . .

I saw something similar with hippos in one doc. One of the males (I don’t think it was the Alpha Male, though) just decided to kill one of the calves.

[Freudian_Slit]

@Earl_Snake-Hips_Tucker

I saw something similar with hippos in one doc. One of the males (I don’t think it was the Alpha Male, though) just decided to kill one of the calves.

Maybe like people, some hippos and zebras are just jerks.

[Fotheringay-Phipps]

@Carryon

I grew up on a farm, and my own experience is people often back explain things to suit them. I would bet the Zebra has no real idea who is or who is not his foal and just killed it.

A big part of the problem is that scientists often speak in shorthand, which lay people misunderstand.

Traits which tend to improve reproductive success are selected for in the animal world. So scientists say things like “this animal does X because it increases his reproductive success”, and people think the animal is consciously attempting to improve his (or her) reproductive success. In reality no animal has any clue about what does or doesn’t improve their reproductive success, and they couldn’t care less about it either. It’s all instincts that they don’t understand but which are selected for.

In this case, an instinct which would cause an animal to kill his own offspring would be selected against, while an instinct that caused him to kill anothers’ offspring might be selected for, in the right circumstances. Exactly what the instinct is is hard to know. Maybe smell, for all I know. Or maybe he kills all foals for X period of time after he takes over the herd. But he has no thought out plan for why he’s doing it - that much is obvious.

[BrightNShiny]

Let’s summarize all the theories presented so far in the thread:

1. Pheromones and smell.

2. Feticide and killing of male foals that weren’t able to be feticided.

3. Timing/killing of all male foals born within a certain time period.

4. Zebras are assholes.

5. Who knows?

Does that cover it?

[Fotheringay-Phipps]

To clarify a bit, when I wrote “X period of time” I was really thinking of the first season. I believe all baby zebras are born at around the same time, and it’s possible that a new stallion kills everyone born the first season (none of them will be his).

[Mr.Milton]

Njtt: Not so far from the truth. I have no cirte ready, but I understand that zebras have variations in their striping patterns that is unique from individual to individual. So while they may all look the same to us, they probably don’t to each other.

[RedSwinglineOne]

@Fubaya

This says:
So, they quit mating once they’re pregnant. He’ll never be able to mate with her until after she gives birth, and once she gives birth, it obviously isn’t his. All he has to do is remember which females he’s gotten lucky with.

This makes perfect sense to me. I’m not sure why we are so quick to assume a zebra is too stupid to remember who he has mated with. In fact, he probably doesn’t need to “remember”. We humans usually feel some kind of connection with others we have mated with. There’s no reason a zebra couldn’t feel the same.

[Tim_T-Bonham.net]

@Jackmannii

And maybe also “get the female to stop paying attention to the foal and focus back on me”.

This is a known action in cats: a tom cat will kill the newborn kittens if they can. Doesn’t seem to matter if the kittens are his or not. Thus the mother moves the kittens to a new nest soon after giving birth.

And it’s not just “focus back on me”. In cats, the females will not mate again until the kittens are a few weeks old. Or dead. So a male killing the kittens will trigger the female to accept mating again.

Of course, cats are not herd animals like zebras, so this probably doesn’t apply to zebra stallions.

[Yllaria]

@BrightNShiny

. . . 1. 2. 3. 4. 5. Who knows?

Does that cover it?

There’s also the possibility that the nature film edited the footing into a better story. Remember the Disney lemmings?