Possible for Zebra to know foal is not his?

I watched a Nature program all about zebras. They claimed that a male who took over the harem when one of the females was only one or two months pregnant knew that her foal was not his foal when it was born almost a year later.

Yes, the male kills the foal, in a very brutal, determined fashion that certainly makes it a believable claim if that is all you consider, but I have a seriously hard time believing that such a thing is possible.

A grudging “maybe” if he took over the harem very shortly before the foal was born, (which still credits him with a stunning degree of intelligence and awareness for a primate, let alone a zebra), but is more believable due to the short time between takeover and birth. *** But almost a year later?? ***By what means? Are zoologists just taking it on faith that this is what is happening without having any explanation for how it is possible? Just assuming that the only possible reason the stallion could have singled out that foal for execution was his sire?

Any insights here?

A new male taking over a harem killing the infants of the prior male is hardly unique to zebras, lions are well known for doing that as well.

It may be that body odor is a factor (a lot of female mammals identify their offspring by odor), but regardless, the male can somehow detect the infants that aren’t his. It doesn’t have to require a lot of intelligence, just the right sort of instinct.

Barcoding. :wink:

This is not what the OP is asking. She is asking about killing infants from pregnant females many months after the male takes over. I’ve not heard of this behavior in lions or other mammals, but I think that it’s often the case that females don’t get pregnant until after they stop nursing.

I don’t know that much about how animals think and stuff, but my understanding is animal sex is t like human sex in that many go through heat and stuff - and if you take over a harem and the female isn’t able/willing to have sex - it doesn’t seem like a great leap of logic for the male to “know” she is pregnant and kill the offspring.

Seems to me this is all stuff like “The Selfish Gene”. He doesn’t actually have to be thinking “that bitch is pregnant - I’m gonna put this on my calendar for 10 months from now.” It would be an instinct. Or perhaps the default is to always kill unless you’ve had sex with her first and stayed with her.

Again these are just guesses. I haven’t seen the Zebra version of Jerry Springer.

If he ran off or killed his predecessor, then it seems logical to think it is instinct for survival of the fittest. Many domesticated animals don’t do this anymore.

Many wild animals can pick out their own from many.

Most any wild animal that lives in herds or groups.
I think it is mostly smell.
The killing is instinct IMO.

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.

I have no idea if you made this up or it is the correct answer, but the logic is excellent, so I consider my question answered unless someone else comes along with something better or more scientifically proven.


Has this actually been scientifically proven? I mean we’ve all heard about it, so there must be quantifiable studies with DNA evidence to support it. Probably by different species, and in comparison to domesticated animals, carnivores vs. herbivores, etc.

  1. Wild male animal consistently kills other male"s offspring when taking over harem. Always? Some offspring but not all? Male offspring? Female offspring?

  2. Wild male animal ever kills his own offspring? Male offspring? Female offspring?

  3. Female animals kill competing offspring to give their own offspring the best chance?

  4. Occurrence in domesticated animals?

This is an interesting question, because I’ve watched all those National Geographic shows, too, and it seems plausible that an incoming male would kill off all offspring that weren’t his.

But do we actually know this to be true?

I wonder. This wiki article indicates that male zebras engage in both infanticide and feticide. So, if they force the pregnant females to abort when they take over the harem, that would give them more certainty that the next batch of foals to come along are theirs.

I don’t really know anything about this topic, though.

Perhaps the reason is that the foal is an unrelated male. Do we know if adult male zebras kill unrelated female foals? Because an unrelated female foal is another breeding partner, whereas an unrelated male foal is competition.

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

Let’s say that the zebra only kills unrelated male foals and not female ones. How does the zebra determine that a male is unrelated?

Pheremones, as stated in previous posts. Is that so mysterious?

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

By stated, you mean “speculated”, right? No one in this thread has offered any documented proof of that.


See John Mace’s post above.

njtt might not be so far off. I think visual clues could be as important as olfactory when it comes to identifying a relative, especially within a species with such a pregnant color pattern as the zebra.

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

I would be curious as to the timing involved in this. A zebra may be wired to kill any off spring born within a certain amount of time within his takeover. I seriously doubt he has any method for determining relations or not.