I remember watching a documentary once and learned that whales need to eat tonnes (literally) of krill per day to survive. I don’t understand why this is better than eating small amounts of large fishes instead.
In: 298
Same reason elephants eat grass, not cattle. Krill are easy to find, available in large quantities and do not fight back or run away.
Because they would still need to eat tons of big fish.
There are far more krill by weight in the sea than there are big fish, so it’s a lot more efficient to eat the krill. After all, the big fish got big by eating smaller fish, so it just cuts a whole stage out.
Usually, bigger animals are herbivores, like elephants and hippopotamus. It’s more efficient to eat the species which create the energy in the first place, rather than eating things further up the food chain.
The immediate reason is that their throats are small enough to choke on a football (NFL or FIFA interpretation).
The bigger reason behind that is they are massive creatures. It would require an enormous expenditure of energy to move fast enough for long enough to catch sizeable prey, which would be an unsustainable survival model. On the contrary, those that kept eating small creatures could stay chill and just open their mouths, which is a more sustainable model.
The latter format won their “survival of the fittest” and now we have the big boys that eat small foods.
The same reason we need to stop eating cows or big animals! Energy efficiency !
The same weight of small animals have much more protein/energy/nutrients…whatever you need compared to the same weight of a big one like cows.
So if the whale wanna eat a bunch of sharks he’s not getting the same amount of nutrients while spending way more effort to catch them. I remember there was an research show that predators like tiger needs to consume 100kg of meat just to gain 1 kg of mass, as you can see, efficient 😅 now talking about human even a little one basically not going weight eating all day and all long life…you can see why the Earth is burning 😅
[removed]
The energy to hunt people have a point but i think the real issue would be finding enough big fish they just aren’t common.
The type of whales you are talking about are filter feeders rather than hunters, they take in about their own mass in water in a single “gulp” and then push the water out through a filter and catch millions of krill against the filter and then eat them, It works and is really efficient and don’t have to chase shoals of fish to find enough to eat.
In evolutionary sense, if there’s free food and no competition for it, then something will evolve to eat it. Even if let’s say this is an inefficient food (which is not the case this time).
There’s huge competition in the large fish eating part of the world and little competition in the krill eaters.
Obviously not all whales eat krill, some do compete in the predator section. But you know if there’s an option to open your mouth and let the krill soup enter, then there will some guys who opt in for that option and slowly evolve that way.
Big fish swim faster than smaller fish, so the latter are easier to catch.
There are more small fish and they swim in schools. Distributing themselves across the ocean would make it harder to be eaten, but then each small fish would have to do all the watching out by itself..
Because of a thing called trophic levels. This is the term given to each step in a food chain. Level one is your primary producers: anything that has chlorophyll and converts sunlight to energy. Next level up are your herbivores, followed by your first level predators and then your apex predators.
The food chain is basically a long line of sales people trying to make money off one bit of labour. Plants/phytoplankton (lvl1) are your farmers, taking raw ingredients and turning them into food. They use some of this food to live: moving, reproducing etc. This is the profit. They store what remains in their bodies either as energy reserves or in growing bigger.
Herbivores(lvl2) are your wholesalers. They take what the farmers have stored and cut themselves a profit to live off. The rest they store in their bodies as either energy reserves or growth.
Predators (lvl3-lvl4) are the companies that buy from wholesalers to divvy up to retailers. They take the energy the wholesalers have, cut themselves a profit to live off, and then store the leftovers as energy reserves or growth.
Apex Predetors (lvl4-lvl5) are the last in the chain, and are the consumer-level retailers. Like everyone else, they take what they need and store the rest.
So you have a line of parties clipping the ticket everytime the energy (money) passes from one level to the next. It’s worth keeping in mind here that moving, reproducing, keeping warm etc counts for 90% of the energy lost at each level. If the phytoplankton produces 1,000 units of energy, the herbivore is only getting 100 units per phytoplankton. The first level of predators is only getting 10 units. The apex predators gets 1. So for an apex predator to get the energy it needs, that’s a lot of individuals that need to be eaten in the course of a food-chain. For this reason, food chains rarely extend beyond 4-5 trophic levels. There’s just no way to extract more value from the same amount of farmers in a given area.
(Edit: I was wrong, it’s actually a limit of 5-6 levels. The concept still holds though)
Whales are huge, and need a lot of energy to maintain that mass. There’s also only so many phytoplankton in the sea. If whales waited for the wholesalers to take their cut, there wouldn’t be enough for the whales to live on. So instead, the whales have evolved to literally cut out the middle men and go straight to the source.
Latest Answers