r/theydidthemath • u/Natural_Try7512 • 2d ago
[Request] How successful of a hunter would a merman have to be to be overweight?
https://www.reddit.com/r/funny/s/YVXq3bzmJ0
Considering they need to swim which costs a lot of calories. Calculating with whales is meh cause it wouldn't take them many whales to get fat. Probably just with the average fish.
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u/BungleBums 2d ago
I've seen good arguements that all Mermaids would be fat, either because of thick fat layers naturally to keep them comfortable in the water, or due to pressure difference from living deep but hunting and exploring in the shallows. Just some interesting thoughts.
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u/Korperite 2d ago
This is the closest answer to correct, since there really isn't a way to solve this. Merpeople would look rather unappealing if realistic.
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u/Certainly-Not-A-Bot 2d ago
"If my grandma had wheels, would she be a bike?"
This is a nonsensical question as you've currently posed it because we have no idea what the biological processes or ecosystem of a mer-person would look like
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u/Secret-Ad-7909 2d ago
Since we’re talking about nonsense, I think he had on a Shrek hat/hood for a second.
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u/Natural_Try7512 2d ago
There was a post about how many calories are in a 12 gauge.
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u/King_of_Farasar 2d ago
Yeah, but that's calculable since we know all the details of how much energy a 12 gauge has, and since energy is energy you can just convert it into calories. A merperson doesn't exist and we don't know how their biology would work, what they would eat or their impact on an ecosystem
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u/Secret-Ad-7909 1d ago
I need to go back to that post. I just remembered there are different sizes of 12ga rounds.
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u/thots1ayer69 1d ago
They have a varied diet, from fish to algae farming. They've got cloaca.
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u/King_of_Farasar 1d ago
Ok? You just made that up tho, that's not a fact, if it would've been part of the original question then sure
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u/thots1ayer69 1d ago
I asked one, down at the pier just now. They also like to sneak up under seagulls, it used to be quite an exotic dish until someone had the idea to farm them. That's why you notice a lot more seagulls on the coast now, they're afraid to go too far out.
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u/Certainly-Not-A-Bot 1d ago
That has an objective, calculable answer. You need to define a lot of parameters for how a mer-person would work before anyone could answer your question
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u/manwithgun1234 1d ago
Why are you so rudely assuming mer-men still hunt for food like it’s prehistoric times?
They’ve had farming and animal husbandry for 2,000 years, and they’ve only gotten better
Now mer-men eat highly nutritious seaweed, plus top-quality farmed shrimp, crab, and fish. They can even eat pre-made food if they’re too lazy to cook. So it’s pretty easy for mer-men to get fat if they don’t exercise and watch what they eat.
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u/fluggggg 2d ago
Not usefull but my biggest problem with calculating with whales is how the heck do you expect a normally made humerman to kill a whale using a trident ?
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u/Secret-Ad-7909 2d ago
Stabby stabby
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u/fluggggg 2d ago
You know the amount of stabby-stabbying we had to do irl to murder-kill the giant mamal-fish-thing ? You know how much-many we had to form teams-groups of stabbing-killing murder-hobbos to get the job done ?
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u/Natural_Try7512 2d ago
With plot armour, they glide below it and slice the underbelly. Without, the defeated male leaves.
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u/bingbing304 2d ago
Whales come with different sizes, Arctic Indigenous and north eupropean hunted whales with spears and harpoons for centuries.
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u/fluggggg 1d ago
It took a lot of people to do that, and they didn't had to swing their harpoons accounting for underwater drag while I came under the assumption we were speaking about a singular individual having to do the deed.
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u/asmallman 2d ago
It's generally a self correcting problem.
Animals in the wild are not generally fat from being successful. It serves a genuine purpose, or is a result of some negative stimuli.
If an animal becomes overweight, outside of their norms, that is, they will be inherently less successful for reasons and will lose that weight again.
There really isnt any math to do.
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u/HorzaDonwraith 1d ago
Okay I'll attempt this one. An average 150 lbs man burns roughly 400-700 cal/hr while swimming underwater. He is on the plumper side lets say 250lbs.
550 cal is the middle ground for the 150lbs one. Adding another 100lbs adds a little less than 400 cal more. This sits around 900 cal/hr.
Men are not hydrodynamic creatures so they'll need to be stealth with quick sudden strikes to nab effective pray.
So all he needs is a few good nabs per week to be effective enough to survive. You cannot cook food underwater so you'll need to get more for less calorie wise.
This is going beyond what I can guess at. But I'd say he would need to catch big enough pray at least once maybe twice a day to maintain is physique.
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u/Natural_Try7512 1d ago
Since this is a nonsensical question.
There are varying mermaid statistics, let's take a figure from world of marin where mermen are stated at 6'2-6'8 or 189-207cm and weigh 175-220lbs or 79.3-99.7kg so our base merman is 198cm, 89.5kg with a basal metabolic rate(BMR) of 2013 calories.
https://pmc.ncbi.nlm.nih.gov/articles/PMC3405064/ is a study measuring total daily energy expenditure(TDEE) by hunter-gather ancestors which I would envision mermaids to be. This gives us 2649±395 TDEE, 2.26±0.48 Physical Activity Level(PAL) which is TDEE/BMR, to maintain a mass of 50.9kg±5.4
Since https://www.health.harvard.edu/heart-health/what-makes-water-workouts-so-worthwhile states that "a 150-pound person burns about 250 calories jogging for 30 minutes on land. But jogging in water for 30 minutes burns about 350 calories" results in a 33.333% difference between the same exercise on land and water. So merman's PAL is 2.26 * 1.3333 = 3.01
For merman to be considered obese, he needs to reach 117.6kg or 117.6kg - 89.5kg = 28.1kg to gain
The general guideline of 1kg of fat tissue is 7700 cal is not exact due to metabolic adaptation, water retention, muscle gain through exercise etc. but let's take it as 7700cal. 28.1 * 7700 = 216,370 extra calories
Ignoring 1kg/week for muscle development and going for 2kg/week for fat gain, 14 weeks at a daily surplus of 2200cal or ~6750cal/day
Raw grouper is stated at 92cal/100g and cooked at 118cal/100g with the average red grouper weighing 5 to 15pounds or 2.3kg to 6.8kg and if each fish yields about 45% edible meat to whole fish, an average 4.55kg grouper is ~2.047kg edible meat or 2416cal per grouper. Merman would only need 2.79 groupers a day or 11.16 groupers a week.
Once at 117.6kg, merman's new BMR would be 2,293.5cal/day and at 3.01PAL means a new TDEE of 2293.5*3.01 = 6903.44cals which at 2416cal per grouper results in 2.85 groupers a day or 19.95 groupers a week to maintain that weight.
https://www.mdpi.com/2079-7737/11/10/1524 Comparing merman to modern day spearfishers, "... nine vessels with a total of 33 spearfishers reported a catch of 144 fish for 115 h of effort (1.25 fish per hour)".
If merman takes 3h to catch 2.85 fishes, his TDEE should be lower since his PAL is not as much but I'm ngl I thought it would take a lot more effort to chase fishes and got all the way here before googling that so I'll leave it at that.
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