Why are horns/antlers/tusks/etc limited to such a small set of niches

[GreatBigBore]

Why is it that nothing mouse-sized has horns/antlers/tusks/etc? It seems that horn-oids(?) are restricted to grazers; I can see why predators wouldn't ever evolve horn-things. But why don't grazing birds and grazing fish get horn-things? Why would horn-things be restricted to such a small, specific set of ecological niches?

 

[Andre]

Well my two cents,

The why probably not ours to assess, but it occurs that assesoires like that are part of a survival mechanism. Interesting is that these ornaments are often related with sexual difmorphism

Interesting are the tusks, while in both modern species of elephants, the genders have well develloped tusks, there was a big sexual dimorphism in the recently extinct woolly mammoth (Mammuthus primigenius):

the male Yukagir mammoth

Can't find a good example of a female tusk now, which are practically rudimentary, but I'll get that soon from the guy in the center of that picture. It should also be noted that the tusk of both genders of the the ancestral mammoths to the woolly mammoth, the steppe mammoth (Mammuthus trogontherii) and before that, the southerly mammoth (Mammuthus meridionalis) were much more like elephant tusks.

It appears that elephants and older mammoth species are associated with habitats with trees, while the woolly mammoth was completely specialized on treeless steppes. Hence it could be speculated that the rather straight tusks of elephants are suitable of bringing down trees, especially those of the extinct straight tusked or forest Elephant (Elephas (Palaeoloxodon) antiquus). But the Woolly Mammoth had no more use for that. So maybe that's why female tusks degenerated while males develloped big ornaments for a better competition with other bulls. And that could be the key, they are mostly male ornaments, intended to win the competition fights before courtship in the struggle for survival of the fittest.

Other species genera and families have different solutions, if required, for that kind of activities.

 

[GreatBigBore]

The why probably not ours to assess

Thanks for the input, but I have to say, this is a contemptible sentiment. I heartily disagree with you. The very essence of discovery, for me, is learning why. Everything else, as it has been said, is stamp collecting.

 

[Evo]

There are horned toads, which apparently are actually small horned lizards.

Horned lizards (Phrynosoma) are a genus of the Phrynosomatidae family of lizards. The horned lizard is popularly called a "horned toad," "horny toad", or "horned frog," but it is neither a toad nor a frog. The popular names come from the lizard's rounded body and blunt snout, which make it resemble a toad or frog. (Phrynosoma literally means "toad-bodied.") The spines on its back and sides are made from modified scales, whereas the horns on the heads are true horns (i.e. they have a bony core).

http://en.wikipedia.org/wiki/Horned_lizard

Horned cowfish

http://animal-world.com/encyclo/marine/puffers/cowfish.php

 

[Monique]

Insects can have horns/antlers as well, such as the Atlas beetle or stag beetle. Then you also have animals such as the thorny devil or aligator snapping turtle that are covered in thorny spikes.

 

[Andre]

Thanks for the input, but I have to say, this is a contemptible sentiment. I heartily disagree with you. The very essence of discovery, for me, is learning why. Everything else, as it has been said, is stamp collecting.

So would that mean that you think that there is anybody that can explain -using the scientific method- why for instance mice did not devellop horns/antlers/tusks.

I meant to say, whilst you can explain what the use of some gadget can be, but you can't explain why some gadget did NOT devellop in some species.

I think the stamp collecting remark is over the top.

 

[GreatBigBore]

So would that mean that you think that there is anybody that can explain -using the scientific method- why for instance mice did not devellop horns/antlers/tusks.

Yes, absolutely. I would not have asked the question if I didn't think that it could be answered.

I meant to say, whilst you can explain what the use of some gadget can be, but you can't explain why some gadget did NOT devellop in some species.

I disagree. Curious people ask this sort of question all the time. Why do two ball-bearings of differing weights fall at the same speed, but a feather weighing the same as a ball-bearing, or even far more, falls very slowly? Humans are far smarter than you seem to think.

I think the stamp collecting remark is over the top.

When Ernest Rutherford said, "Physics is the only real science. The rest are just stamp collecting," he was wrong. I would agree with you that such a statement is preposterous. However, that's not what I said. I said that everything that doesn't involve explanation is stamp collecting.

 

[Monique]

Since the original question has been proven invalid, this topic is closed.