Are scavengers edible?

[calebprime]

Not that small a part. By number we're certainly outnumbered by many insect species, but by mass we about equal to the ants. I suspect that of large animals only our livestock species outweigh us in biomass, if any do at all.

For instance there are about 1.4 billion cattle in the world and they have an average weight of 750kg, so that gives us a total mass of about 1 trillion kg. Humans on the other hand weigh maybe around 500 billion kg total.

Oh wow, googling a bit I actually found that there's an XKCD for this, though it only includes land mammals, still as I suspected humans make up a pretty large proportion, and wild mammals are almost insignifcant:

[qimg]https://imgs.xkcd.com/comics/land_mammals.png[/qimg]

Amazing, and what a good way to picture it. Hope the info is solid.

 

[Roboramma]

Amazing, and what a good way to picture it. Hope the info is solid.

Randal Munroe (the guy who writes XKCD) tends to be pretty good with his research and has the type of following (nerds) who would very likely call him out if he does make mistakes, so I think we can view it as a pretty solid source.

It also matches pretty well with the numbers I quickly googled for cattle at least.

 

[William Parcher]

Do vultures taste very bad or something?

Vultures are really the only obligate terrestrial scavengers that are vertebrates.

Here's a jackal eating a vulture...

https://m.youtube.com/watch?v=rK2SYu1Us-g

 

[MRC_Hans]

Is there any reason of carnivores tend to be less plentiful? Whether exitiction or logevity of survival, anyway related to carnivorous, omnivorous or Herbivores?

Really, Kumar, can't you figure out why?

Hans

 

[Ron Swanson]

Vultures are eaten in many countries, in others its considered 'taboo' ... there's recipes on line people, do eat them ...

Apearently roasted Vultures have been sold as Chicken meat and the people buying didn't even know the difference ... until the seller was actually CAUGHT with live Vultures.

https://www.expertsure.com/2009/09/07/vultures-killed-and-sold-as-roasted-chicken/

 

[bruto]

Amazing, and what a good way to picture it. Hope the info is solid.

It is interesting and informative, but I think the point I was making is not changed. Population is counted in numbers. We should not be unconcerned that there are so few blue whales left in the world, simply because they outweigh a countless number of flies.

In terms of the number of species and the number of members of species, we are not all that important, and I do not think that, as Kumar seems to, there is some moral rule in nature that favors herbivores.

 

[ddt]

It is interesting and informative, but I think the point I was making is not changed. Population is counted in numbers. We should not be unconcerned that there are so few blue whales left in the world, simply because they outweigh a countless number of flies.

In terms of the number of species and the number of members of species, we are not all that important, and I do not think that, as Kumar seems to, there is some moral rule in nature that favors herbivores.

Wiki has several lists of animals by population count.

There are 7 billion humans on the planet. I only checked the lists of mammals; there, the only species that measure around 1 billion are cattle, pig and sheep. There's no list of estimates for rodents, though; some species of rat or mice might outclass us in numbers. But this small samples shows that humans are, in terms of population numbers, wildly successful.

 

[bruto]

Wiki has several lists of animals by population count.

There are 7 billion humans on the planet. I only checked the lists of mammals; there, the only species that measure around 1 billion are cattle, pig and sheep. There's no list of estimates for rodents, though; some species of rat or mice might outclass us in numbers. But this small samples shows that humans are, in terms of population numbers, wildly successful.

There is no question that we are wildly successful, and that we've outnumbered (as well as killed off) a lot of other animals. But mammals are not the only critters in the mix either. I'm not sure we'd stack up quite so well against starlings, mosquitoes and krill.

 

[Roboramma]

It is interesting and informative, but I think the point I was making is not changed. Population is counted in numbers. We should not be unconcerned that there are so few blue whales left in the world, simply because they outweigh a countless number of flies.

The blue whales certainly do not outweigh the flies.

There are at most 25,000 blue whales in the world. With an average weight of say 100,000 kgs (probably high), that's a total mass of 2,500,000,000, 2.5 billion kgs.

Apparently there are about 1.2 x 10¹⁷ flies in the world. Let's take an average weight of 1 mg/fly. That would be 1.2 x10¹¹ kg of flies in the world, or about 120 billion kg of flies, so about 50 times more mass than there is in blue whales.

The reason to consider biomass the reasonable measure is that it is a good proxy for a species' importance in an ecosystem. With some caveats the proportion of an ecosystem's biomass which is made up of that species could also be considered a good proxy for the proportion of total energy in an ecosystem that is used by that species.

In terms of the number of species and the number of members of species, we are not all that important,

In terms of number of species, sure, we are one out of perhaps tens of millions of species on earth. But that's not particularly interesting is it? In terms of our effect on the biosphere we perhaps have a similar impact to things like ants or flies, which is very considerable indeed.

Moreover, we use 25% of the earth's net primary production, that is, of the energy converted through photosynthesis, 25% is used by humans.
http://www.pnas.org/content/110/25/10324.full

This is an even greater proportion of the total than is suggested by our biomass, which isn't surprising since technology allows us to put the energy we consume to many uses other than growing and moving around bodies.

ETA I feel I was clear but just in case, I'd like to note that this is only taking the energy of photosynthesis into account, not fossil fuels. So, agriculture, forestry, etc.

and I do not think that, as Kumar seems to, there is some moral rule in nature that favors herbivores.

Certainly I agree with that.

 

[Kumar]

Really, Kumar, can't you figure out why?

Hans

I felt, it may be like derailing the thread so quoted in other topic:

CORVALLIS, Ore. – In ecosystems around the world, the decline of large predators such as lions, dingoes, wolves, otters, and bears is changing the face of landscapes from the tropics to the Arctic – but an analysis of 31 carnivore species to be published Friday in the journal Science shows for the first time how threats such as habitat loss, persecution by humans and loss of prey combine to create global hotspots of carnivore decline.

More than 75 percent of the 31 large-carnivore species are declining, and 17 species now occupy less than half of their former ranges, the authors reported.
http://oregonstate.edu/ua/ncs/archi...-carnivores-poses-global-conservation-problem

 

[Roboramma]

Really, Kumar, can't you figure out why?

Hans

The more interesting thing is that the photosynethising (not a word but it should be) organisms in the ocean are outweighed by those that eat them.

 

[ddt]

There is no question that we are wildly successful, and that we've outnumbered (as well as killed off) a lot of other animals. But mammals are not the only critters in the mix either.

Fair enough.

I'm not sure we'd stack up quite so well against starlings,

European or African starling?
(More seriously, starlings are a family of species).

mosquitoes and krill.

Bingo. Antarctic krill:

It is a key species in the Antarctic ecosystem and is, in terms of biomass, probably the most abundant animal species on the planet (approximately 500 million tonnes, corresponding to 300 to 400 trillion individuals)

But we're working on changing that:

Alarmingly, there are recent studies that show Antarctic krill stocks may have dropped by 80 percent since the 1970s. Scientists attribute these declines in part to ice cover loss caused by global warming. This ice loss removes a primary source of food for krill: ice-algae.

 

[LTC8K6]

He'd have been very disappointed, then. His action would have had no impact on the survival of that hyaena clan, and nor would it have changed their behaviour. Hyaenas are very good at avoiding contact with lions unless they want it. My daughter actually tracked hyaenas on the Maasai Mara for 4 months, plotting their whereabouts in relation to that of lions. Hyaenas are often the apex predators in areas where lions have been killed off, such as Liuwa in Zambia.

There almost seemed to be a personal animosity between that male lion and that alpha female hyena. That hyena always seemed to taunt that lion at a kill or whenever the groups were near each other. That one hyena always seemed to test that lion's patience.

 

[Roboramma]

Bingo. Antarctic krill:

It looks like they are still outweighed by cattle, or at least within the same range. I had it at 1 trillion kg, or 1 billion tonnes, which is twice the number you have for krill. On the other hand XKCD is somewhere around half what I gave (I didn't bother to count the boxes exactly, just approximately), which would be about the same as the mass for krill.

 

[bruto]

I do get the point that biomass is a very important factor in many considerations. We are certainly at the top of the food chain and all that. My specific response, as noted, was to Kumar's notion that nature has some innate preference for herbivores because there are more of them and that nature is guided by some moral principle.

Plenty of critters in nature are carnivorous, and plenty of carnivores eat other carnivores.

 

[William Parcher]

To answer the OP: Apparently yes. Vultures are on the prey list of hawks, eagles and large owls. So they are edible and they are obligate scavengers adapted to eating toxic rotten flesh. I posted a video of a jackal eating a dead vulture. Other mammals and birds might eat dead vultures as well.

 

[RecoveringYuppy]

It looks like they are still outweighed by cattle, or at least within the same range. I had it at 1 trillion kg, or 1 billion tonnes, which is twice the number you have for krill. On the other hand XKCD is somewhere around half what I gave (I didn't bother to count the boxes exactly, just approximately), which would be about the same as the mass for krill.

So what is the mass of the grass (or whatever) the cattle graze on? And how much of that is planted and displacing whatever was growing naturally I wonder?

 

[Roboramma]

I do get the point that biomass is a very important factor in many considerations. We are certainly at the top of the food chain and all that. My specific response, as noted, was to Kumar's notion that nature has some innate preference for herbivores because there are more of them and that nature is guided by some moral principle.

Plenty of critters in nature are carnivorous, and plenty of carnivores eat other carnivores.

Yeah, sorry about that, I do agree with you in the context of your exchange with Kumar, I was simply disagreeing about the way you were making the argument.

Kumar's ideas are strange enough that I'm not sure I even want to go into them.

 

[Damien Evans]

A cheetah is the fastest land animal on the planet. I'm sure it can jump a vulture. They are rather slow when on the ground.

Hans

for a tiny burst, sure. But they have no stamina.

 

[Roboramma]

So what is the mass of the grass (or whatever) the cattle graze on?

That's an interesting question. I don't know the answer, but I think a good guess is about 10 times the mass of the cattle that are grazing on it, so somewhere between 5 and 10 trillion kgs?*

And how much of that is planted and displacing whatever was growing naturally I wonder?

That's interesting as well. I think that the percentage of cattle's diet that's grain-based vs. grazing will depend on the country they are being raised in, so I found this:

So that might be informative, but we still need to know more about the agricultural practices of each country.

I did find this:
https://en.wikipedia.org/wiki/Cattle_feeding

Animals grazing in rangelands, pastures, and grasslands and with little or no integration of crops involved. About 60% of the world's pasture land is covered by grazing systems. Grazing systems supply approximately 9 percent of the world's production of beef, according to Food and Agriculture Organization statistics.

But this is relative to two other possible feeding practices, "Integrated Livestock-Crop Farming" and "Industrial Production". The problem is that "Integrated Livestock-Crop Farming" still seems to include a considerable amount of grazing, but how much? And since:

Mixed farming systems are the largest category of livestock system in the world

It's hard to quantify at this point.

I'm sure I could get closer to a real answer with more research but at this point I don't really have an answer yet.




*This number of course should include the grains that grain-fed cattle are eating. Which leaves us with the question of whether our agricultural systems have achieved a greater than 10% efficiency of turning grain-mass into cow-mass? I actually doubt it, but it's worth considering.