Why so few nidicolous herbivores?

[snorkack]

Well, why?
And the herbivores who are nidicolous are small herbivores like rabbits.
With the one exception of sow.

Why?
And, on the other hand, why are carnivores nidicolous?
Kittens, puppies and cubs are born blind.

Sure - small herbivores like hares and sheep are popular prey for big carnivores.
But a lot of herbivores are big compared to carnivores present in their environment.
A cow is big and horny compared to a sow. For a wolf or a bear, a cow should be a more daunting target - and an elephant even more so. If an elephant made a nest, who would dare bother her in her nest?

Actually, it would seem to me that carnivores and even omnivores should be less, not more suited for nesting than herbivores.
For the food of carnivores is capable of fleeing them or migrating for their own reasons. If a jerk has blind puppies in den, and the potential prey flee the surroundings in fear of the jerk, the jerk and her puppies would starve until the puppies are big enough to leave the nest in pursuit of their prey. Whereas a cow, if she wanted to nest, could verify the presence of enough grass around her nest, and see to it that no one else eats it until her calf is ready to leave the surroundings.
As for omnivores, since a sow being omnivore cannot eat grass like a cow does, but is limited to more nutritious and scarce foods, she also needs a bigger home range than a herbivore of same size.

And for the example of carnivores - if a bear could bear a cub as big and mobile as a newborn calf, they would not be confined to vicinity of a den, but could migrate in pursuit of prey.

So why are herbivores so overwhelmingly nidifugous, and carnivores nidicolous?

 

[ProfuselyQuarky]

I don't think that there's a solid answer for the connection between an animal being an herbivore/carnivore and altricial/precocial. Perhaps it is just that animals who are herbivores are prey to the carnivores, so they have to be able to fend for themselves at a much earlier age. If herbivores were nidicolous, the chances of the young of the species being preyed on would be much higher, since they would be so vulnerable.

 

[Pythagorean]

The sources I'm seeing suggest carnivores tend to have larger brains, larger brains tend to lead to birth earlier in development, with some caveats.

"Relatively large brained mammals, altricial and precocial, also show reduced annual fertility rates as compared to their smaller brained relatives, but allomaternal energy inputs allow some cooperatively breeding altricial carnivores to produce even more offspring in a shorter time despite having a relatively large brain. Thus, the Expensive Brain framework explains why brain size is linked to life history pace in some, but not all mammalian lineages. This framework encompasses other hypotheses of energetic constraints on brain size variation and is also compatible with the Brain Malnutrition Risk hypothesis, but the absence of a mammal-wide correlation between brain size and immature period argues against the Needing-to-Learn explanation for slower development among large brained mammals."

http://www.ncbi.nlm.nih.gov/pubmed/19732937

(Note that nidicolous often only refers to nesting stay, whereas altricial refers to developmental progress at birth.)

 

[snorkack]

Hare and rabbit are both herbivores, both popular prey for predators, similar in size and closely related.
Which of them is smarter? Does the newborn leveret being too smart and too well developed come to hinder it from further development with the result that adult hare ends up being dumber than the adult rabbit?

 

[dipole]

Well, a large majority of reptiles and amphibians are carnivorous, as are many fish, and they are almost entirely nidifugous. They are also vastly more stupid than mammals and birds which exhibit nidicolous offspring. As already pointed out, the trend seems to be about brain development, not diet.

 

[snorkack]

Well, a large majority of reptiles and amphibians are carnivorous, as are many fish, and they are almost entirely nidifugous. They are also vastly more stupid than mammals and birds which exhibit nidicolous offspring. As already pointed out, the trend seems to be about brain development, not diet.

Yes, but a question is, is being stuck to a nest for a prolonged time a liability?
Birds are obligate nesters because they are unable to give live birth. Most mammals and a few reptiles are able to give birth. So their young may be bound to nest after birth or they may not need a nest at all.
(Marsupials and most primates are altricial but capable of carrying outside a baby born, so also not stuck to a nest.)

 

[Evo]

I just have to make an off topic, meaningless post here that every time I see this thread title I read "Why so few ridiculous herbivores?"

Nevermind. Nothing to see here, move along.

 

[ProfuselyQuarky]

I just have to make an off topic, meaningless post here that every time I see this thread title I read "Why so few ridiculous herbivores?"

Nevermind. Nothing to see here, move along.

Oh, good. So I wasn't the only one!

 

[Evo]

Oh, good. So I wasn't the only one!

Thank goodness!

 

[jim mcnamara]

What you are discussing is part of a concept called r and K selection.
r selected organisms are those which produce more offspring and have fewer members of a cohort survive to reproductive age.
They exhibit a survivorship curve tending toward type III. Example rodents: and lagomorphs (rabbits).
Humans are K selected, few offspring, less early mortalilty, later age at the start of reproduction, and generally have a larger encephalization quotient (adult brain mass/adult boy mass). Longer maturation period. They are Type I. Extreme examples: Humans, cetaceans.

https://en.wikipedia.org/wiki/Survivorship_curve
https://en.wikipedia.org/wiki/R/K_selection_theory

Plus, IMO, we should exclude domesticated animals from the discussion. In terms of body and sometimes brain mass ratios what we see is the result of breeding.

 

[snorkack]

Plus, IMO, we should exclude domesticated animals from the discussion. In terms of body and sometimes brain mass ratios what we see is the result of breeding.

Only 3 domesticated animals are extinct: dromedary (unknown), cow (in Poland in 1627) and horse (in Ukraine in 1879). All others, like wild, never domesticated wolf, cat, ass, sheep, goat and swine are very much around, even if some of them are rare.

 

[jim mcnamara]

@snorkack - I fail to see your point. You cannot cherry pick examples for this in Biology, except to choose to examine animals that exist in wild populations. This is because you are asking "why?" to a specific question. The generally accepted "rule" for this was shown above. It does not really apply to domestic species because humans control the environment - i.e., they completely control which individuals reproduce. This means Natural Selection is almost completely overridden. Wild "teacup poodles" would likely fare poorly in the wild. Regardless of how "cute" they may be.

http://www.dogbreedinfo.com/t/teacuppoodle.htm

Ask a general question. Get a general answer. Please consider citing references on topic instead of going on about this species and that species. Thank you.

 

[snorkack]

@snorkack - I fail to see your point. You cannot cherry pick examples for this in Biology, except to choose to examine animals that exist in wild populations. This is because you are asking "why?" to a specific question. The generally accepted "rule" for this was shown above. It does not really apply to domestic species because humans control the environment - i.e., they completely control which individuals reproduce. This means Natural Selection is almost completely overridden. Wild "teacup poodles" would likely fare poorly in the wild. Regardless of how "cute" they may be.

Domestic dog is unusually plastic. But wolf is very much extant, so we can easily verify what wolf is like. The other domestic animals are much less divergent from the wild form.
It is a matter of argument whether domestic animals are species. The current position is they are not. It is certainly agreed that no genera have ever been bred.

As for nidicolity, all breeds of dog bear blind puppies, just like wolves.
My general impression is that most large herbivores are nidifugous. I quoted potential counterexamples - swine (omnivores rather than herbivores), rabbits (small rather than large herbivores).
Before you can get to quoting "references", indeed searching for them, it is necessary to find out if the question has been asked before, or indeed which terminology has been invented to talk about the topic.
r and K strategies I´ve heard about. My question was, why are herbivores picking K strategy and carnivores, even apex predators, r strategy. Why should a sheep bear a single lamb and a wolf a whole litter? Nobody is preying on wolves (OK, excluding the bigger apex predators like tigers and lions, where they meet - but lions also bear litters).

 

[Jon Richfield]

I may have missed something, but one of the first things is that herbivores generally have less concentrated food, so they have to be moving around to collect it all the time. Many of them actually eat largely on the move, and the larger they are, the larger the area they tend to need to graze (like the cube of their dimensions). Besides, for them to build a nest is a bit of a challenge, especially if they want the nest to be unobvious to predators.
For rabbits and mice and even small antelope such as Raphicerus spp. the problem is less acute, and though Raphicerus species are not actually formally nidicolous, they are more inclined to leave their young in a sort of a set in the grass or scrub.
A carnivore can get more energy from a single prey item than a herbivore from a a couple of days foraging, and they can carry it back in various ways as a rule (exceptions? sure! This is biology, remember!) and carnivores tend have less of an acute predation problem, so their nests can be less carefully hidden (but just TRY finding them!)
There is a trend this way even with birds. Nidifugous birds' chicks such as gallinaceous species tend to forage as precocious omnivores instead of staying in the nest. Some ease the critical period by focussing on more concentrated food; eg goslings even forage as predators of small invertebrates rather than grazing on coarse fodder all over the place. Nidicolous birds tend to feed their chicks either more concentrated food, or predigested food, or even milk. Seed-eating passerine birds that raise their chicks in nests tend to feed them on insects, especially in the first couple of weeks. Check out finches and sparrows.
The topic is a wide one, So don't expect to get a single neat answer. It is full of ifs ands and buts. Pardon the hasty answer; a proper one would take a book, even for a homework project.

 

[Andrew Juggler]

I have trouble picturing millions of bison nests dotting the American plains.

 

[Jon Richfield]

I have trouble picturing millions of bison nests dotting the American plains.

Quite.
Or wildebeest (gnu) in Africa!

 

[snorkack]

I may have missed something, but one of the first things is that herbivores generally have less concentrated food, so they have to be moving around to collect it all the time.

But the food of herbivores is not running away from them.

Besides, for them to build a nest is a bit of a challenge, especially if they want the nest to be unobvious to predators.

Yes, but a big herbivore like a cow or elephant might not care to make her nest unobvious - she might rely on her size and her horns/tusks to fight off any predator who´s so stupid as to approach her nest.

 

[Jon Richfield]

But the food of herbivores is not running away from them.

Yes, but a big herbivore like a cow or elephant might not care to make her nest unobvious - she might rely on her size and her horns/tusks to fight off any predator who´s so stupid as to approach her nest.

And?

 

[BillTre]

I tend to agree with @Jon Richfield. A herbivore with a significant threat of predation will have to either be ready to go when born or have a secure place to hide away in. If they are large, difficult to hide herbivores, moving around for food, then the young have to keep up.

IMO, large herbivores sitting around defending an easily found nest would just draw a lot of predators. At least one parent would have to defend the nest constantly and would not be able to get food. This would not work well since herbivore parents don't (to my knowledge) bring food back to the nest (of course that would have to evolve, but the volume of food for them is large, making the task difficult (making failure more likely)). Carnivores can leave a parent at a nest to guard, because they can bring food back "home".

The greater the parental investment in the offspring, the more important these considerations are. Fish laying a million eggs have relatively little investment in each offspring (a K vs. r argument). Parental care is not so common among fish.

 

[Jon Richfield]

A herbivore with a significant threat of predation will have to either be ready to go when born or have a secure place to hide away in. If they are large, difficult to hide herbivores, moving around for food, then the young have to keep up.

IMO, large herbivores sitting around defending an easily found nest would just draw a lot of predators. At least one parent would have to defend the nest constantly and would not be able to get food. This would not work well since herbivore parents don't (to my knowledge) bring food back to the nest (of course that would have to evolve, but the volume of food for them is large, making the task difficult (making failure more likely)). Carnivores can leave a parent at a nest to guard, because they can bring food back "home".

Correct. Also, large mammalian herbivores (say sheep-size and up) are inclined to over-graze local plant materials in a region very soon, except for high-density, high-productivity ecologies like rainforests and reed beds, so they cannot really bring back the large volumes of plant food that young would need. In fact, it is in just such densely grown regions that one finds the closest one gets to nests for the newborn.

And even then the food brought back to baby is in the concentrated form of milk (and the next meal in the form of food in the gut or rumen. Highly frugivorous large mammals tend to be competitive and fight for their favoured trees (eg orang utans).
In the case of gnu, zebra and some gazelles etc the baby has to run from day 1.
Small herbivores like some rodents and Lagomorpha (such as marmots and pika) do lay in winter stores and do defend them, but those are adaptations to special circumstances such as rocky shelters with sparse or distant feed.

It is a matter of adaptations to historical and special circumstances. Also evolutionary opportunism. It is easy to rationalise results after the fact, but not always easy to predict.

 

[snorkack]

IMO, large herbivores sitting around defending an easily found nest would just draw a lot of predators. At least one parent would have to defend the nest constantly and would not be able to get food. This would not work well since herbivore parents don't (to my knowledge) bring food back to the nest (of course that would have to evolve, but the volume of food for them is large, making the task difficult (making failure more likely)). Carnivores can leave a parent at a nest to guard, because they can bring food back "home".

Only the few carnivores with paternal care, like wolves.
Most carnivores, such as cats and bears, are single mothers and therefore the kittens are defenceless when the mother leaves the nest to hunt.
A sow is an omnivore, and does nest - as a single mother. While the roots will not flee the nest of the sow, she still is limited to the high quality plant food, and has to pick these from a large area.
It seems to me that a cow, as a herbivore eating grass and leaves, should be able to feed herself and her young from a smaller area than the sow, or be bigger and more dangerous defender with the same home range.

 

[Jon Richfield]

Only the few carnivores with paternal care, like wolves.
Most carnivores, such as cats and bears, are single mothers and therefore the kittens are defenceless when the mother leaves the nest to hunt.
A sow is an omnivore, and does nest - as a single mother. While the roots will not flee the nest of the sow, she still is limited to the high quality plant food, and has to pick these from a large area.
It seems to me that a cow, as a herbivore eating grass and leaves, should be able to feed herself and her young from a smaller area than the sow, or be bigger and more dangerous defender with the same home range.

Sows like high-quality food, and prefer the highest quality, namely meat and eggs. However, we don't call pigs omnivores for nothing. Where feeding is good, like in thickets of root plants such as everything from grasses with rhizomes or Typha, to underground-storage-based plants such as Watsonia, Crocosmia, or Zantedeschia, she might be able to satisfy her farrow almost within her own body length of her "nest". And she can survive on low-grade plant matter indefinitely. Within a day or two of farrowing, she can go walkabout and the whole family all abandon the nest as soon as they like. A sow, or a sounder of wild swine, with their prettily patterned piglets trotting behind is a charming sight almost anywhere in the world, and the distance that their babies can travel is not a limiting factor.

Precisely because the food a cow eats is rarely anything like as high-quality as the pig forage, she has to load it in by the bucketful, and that demands a large area no matter what that seems to you. Cows too (though not all herbivores) have calves that can follow them about within a day or two. But if you think that a cow (and some of them can be very formidable) is more dangerous than a recently farrowed sow, your animal husbandry education is sadly lacking -- don't even think about going near such a sow; they have no sense of humour at all, but lots of mass, tooth, muscle and more speed than you might expect. A writer who knew pigs wrote on the subject; you can check him out online at http://www.eastoftheweb.com/short-stories/UBooks/Hyac.shtml
Mind the scannos though. at one point they have "pit" where the original was "pig".