eli5: Why are herbivorous animals usually fatter/bigger than carnivorous animals?

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eli5: Why are herbivorous animals usually fatter/bigger than carnivorous animals?

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Anonymous 0 Comments

Only certain ones are big, and many herbivores are tiny and agile, at least compared to their predators. But the very large ones use size to their advantage. It’s just hard to bring down a moose or a wildebeest or a buffalo or a hippo. So from an evolutionary standpoint, the bigger herbivore just kept getting bigger and bigger because size provided a survival advantage. There are still lots of smaller and faster herbivores who use their speed as a survival advantage, like deer and gazelle and animals like that.

Anonymous 0 Comments

A carnivorous animal has to be fast enough to catch its prey.
A herbivorous animal has to as well, but plant’s don’t move fast at all.

Being big/fat makes you slower.
So if a carnivore was too big/fat it wouldn’t be able to catch it’s prey.
While being big/fat makes you resistant to a whole lot of things.
So some herbivores became as big as possible, so they could fight off predators, while other kept small so they could run away from predators.

Anonymous 0 Comments

A carnivorous animal has to be fast enough to catch its prey.
A herbivorous animal has to as well, but plant’s don’t move fast at all.

Being big/fat makes you slower.
So if a carnivore was too big/fat it wouldn’t be able to catch it’s prey.
While being big/fat makes you resistant to a whole lot of things.
So some herbivores became as big as possible, so they could fight off predators, while other kept small so they could run away from predators.

Anonymous 0 Comments

A carnivorous animal has to be fast enough to catch its prey.
A herbivorous animal has to as well, but plant’s don’t move fast at all.

Being big/fat makes you slower.
So if a carnivore was too big/fat it wouldn’t be able to catch it’s prey.
While being big/fat makes you resistant to a whole lot of things.
So some herbivores became as big as possible, so they could fight off predators, while other kept small so they could run away from predators.

Anonymous 0 Comments

Only certain ones are big, and many herbivores are tiny and agile, at least compared to their predators. But the very large ones use size to their advantage. It’s just hard to bring down a moose or a wildebeest or a buffalo or a hippo. So from an evolutionary standpoint, the bigger herbivore just kept getting bigger and bigger because size provided a survival advantage. There are still lots of smaller and faster herbivores who use their speed as a survival advantage, like deer and gazelle and animals like that.

Anonymous 0 Comments

Only certain ones are big, and many herbivores are tiny and agile, at least compared to their predators. But the very large ones use size to their advantage. It’s just hard to bring down a moose or a wildebeest or a buffalo or a hippo. So from an evolutionary standpoint, the bigger herbivore just kept getting bigger and bigger because size provided a survival advantage. There are still lots of smaller and faster herbivores who use their speed as a survival advantage, like deer and gazelle and animals like that.

Anonymous 0 Comments

First of all, I don’t think this is true. Many herbivorous animals are tiny. You’re probably not thinking about the sizes of all animals – you’re probably noticing that most of the largest animals are herbivores.

The main advantage of being large are:
– you don’t need to be able to run or hide from as many predators, or from any, if you are large enough.
– you probably don’t need to find food every day, as you can store some reserves as fat. (Small animals can do this too, but their energy requirements are actually higher *relative to their body size*, so they usually can’t go as long without food, unless they have ways of drastically slowing their metabolism and becoming inactive.)

The disadvantages are:
– above a certain size, you’re less fast and agile
– you will need loads of food in total to maintain your size

For some herbivores, the disadvantages aren’t very strong. If they live somewhere where their food is plentiful and easy to find, then being large is an option. And you don’t have to be fast or agile to eat fruits, leaves or grass. For carnivores however, these disadvantages quickly become huge. Imagine a carnivorous elephant trying to catch an antelope, and needing to catch lots to survive, and you’ll see the problem.

For carnivores, the cons of being large tend to outweigh the pros for very large body sizes. For some herbivores, the pros still outweigh the cons up to a higher ceiling.

For many animals, including herbivores, it still makes more sense to be small, it’s just that the ceiling for how large you potentially can be tends to be higher for herbivores.

There are other factors too (e.g. you can read about r vs K reproductive strategies), but this is a good start.

Anonymous 0 Comments

First of all, I don’t think this is true. Many herbivorous animals are tiny. You’re probably not thinking about the sizes of all animals – you’re probably noticing that most of the largest animals are herbivores.

The main advantage of being large are:
– you don’t need to be able to run or hide from as many predators, or from any, if you are large enough.
– you probably don’t need to find food every day, as you can store some reserves as fat. (Small animals can do this too, but their energy requirements are actually higher *relative to their body size*, so they usually can’t go as long without food, unless they have ways of drastically slowing their metabolism and becoming inactive.)

The disadvantages are:
– above a certain size, you’re less fast and agile
– you will need loads of food in total to maintain your size

For some herbivores, the disadvantages aren’t very strong. If they live somewhere where their food is plentiful and easy to find, then being large is an option. And you don’t have to be fast or agile to eat fruits, leaves or grass. For carnivores however, these disadvantages quickly become huge. Imagine a carnivorous elephant trying to catch an antelope, and needing to catch lots to survive, and you’ll see the problem.

For carnivores, the cons of being large tend to outweigh the pros for very large body sizes. For some herbivores, the pros still outweigh the cons up to a higher ceiling.

For many animals, including herbivores, it still makes more sense to be small, it’s just that the ceiling for how large you potentially can be tends to be higher for herbivores.

There are other factors too (e.g. you can read about r vs K reproductive strategies), but this is a good start.

Anonymous 0 Comments

First of all, I don’t think this is true. Many herbivorous animals are tiny. You’re probably not thinking about the sizes of all animals – you’re probably noticing that most of the largest animals are herbivores.

The main advantage of being large are:
– you don’t need to be able to run or hide from as many predators, or from any, if you are large enough.
– you probably don’t need to find food every day, as you can store some reserves as fat. (Small animals can do this too, but their energy requirements are actually higher *relative to their body size*, so they usually can’t go as long without food, unless they have ways of drastically slowing their metabolism and becoming inactive.)

The disadvantages are:
– above a certain size, you’re less fast and agile
– you will need loads of food in total to maintain your size

For some herbivores, the disadvantages aren’t very strong. If they live somewhere where their food is plentiful and easy to find, then being large is an option. And you don’t have to be fast or agile to eat fruits, leaves or grass. For carnivores however, these disadvantages quickly become huge. Imagine a carnivorous elephant trying to catch an antelope, and needing to catch lots to survive, and you’ll see the problem.

For carnivores, the cons of being large tend to outweigh the pros for very large body sizes. For some herbivores, the pros still outweigh the cons up to a higher ceiling.

For many animals, including herbivores, it still makes more sense to be small, it’s just that the ceiling for how large you potentially can be tends to be higher for herbivores.

There are other factors too (e.g. you can read about r vs K reproductive strategies), but this is a good start.

Anonymous 0 Comments

It’s mostly a Perception thing on your part. Animals will generally adapt to fill a niche. The largest animal ever the blue whale is a carnivore. But it doesn’t need to move too fast to catch its prey. The lion has to catch its food being too big makes that difficult. As to why some herbivores are larger depends what they eat. A lot of larger herbivores like Buffalo are called ruminants they have complex stomachs to digest plant matter in an efficient way. But they have to eat a lot of material and spend large portions of their day just grazing. On the small side many rodents or birds ( generally small animals) are herbivorous but target high calorie easy to digest foods like nuts, fruits, or flowers.

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