Roughly how many calories per day does a mammal need in cold weather?

Not sure how helpful this is, but Milo weights about 13lbs. 7 oz and eats c. 1 cup of Hill’s prescription tartar-control per day

Package says “268 kcal/cup.” I am not sure what a “kcal” is either.

He gets a bit more from crumbs of cheese, chicken, a cat treat or two and sneak licks of butter or cream cheese when my back is turned. He is in and out all day long.

I have never seen him (ever) go after anything larger than a chipmunk. But, of course, he knows he has a food supply waiting.

@gailcalled
it means “kilocalorie” it is the energy required to increase the temperature of 1l of water by 1°C

How does that translate into a calorie. And wnat is 1l ?

1l is 1000ml.
in the case of water, it equates to 1kg, or 1000g
and a kilocalorie is 1000 calories.

A kilocalorie is one capital C Calorie. Calorie measurement of food in the US is in kcals.

It’s not just the body weight of the mammal, it’s also the metabolism rate. A sloth burns much less calories per pound than a ferret.

Just found this, which makes more sense for poor Milo’s waistline. 268,000 calories/day seems a tad excessive.

” Common usage in the US is that a calorie is the same as a kcal (as far as nutrition labels are concerned anyway). Other countries (esp. European ones) tend to use kcal instead….”

Metabolically, Milo ranges from cheetah-like sprints to long periods of sloth-like torpor and snoozing daily. A present he is awake but immoble and staring fixedly at a bare wall.

Obviously it depends on the size of the mammal, it’s activity levels and weather conditions.
Horse need mega calories depending on their age, amount of work they do and if they are lactating. A mega calorie is 1000 kilocalories, Megacalories are the unit measures of energy for maintaining a large animals needs such as a horse. A lactating female of any species needs more calories as does a working animal.

According to a chart I was just reading these are the requirements.

Weanling ( 4 months of age ) 14.4 Mcals
Yearling ( 12 months if age -moderate growth ) 18.9 Mcals
2 year old ( not training ) 18.8 Mcals
2 year old ( in heavy training ) 26.3 Mcals
Adult maint. 16.4 Mcals
Working horse ( light work ) 20.5 Mcals
Working horse ( moderate work ) 24. 6 Mcals
Working horse ( intense work ) 32. 8 Mcals.
Lactating mare ( 1st 3 months ) 28.4 Mcals.

The horses here are performance mares, get daily workouts, compete in shows and while I do not know the exact ratio of calories in their feed they are moderately to intensely worked depending on the season.
We feed 10–12 lbs. of an Alfalfa/grass hay blend 2 x daily, morning and night with nightly performance supplements of about 1.5 lbs. of high density grain supplements with rice bran and vitamins.

Let’s call kcal and food Calorie the same. Close enough for this Q.

That number is lining up with what I have seen experimentally. If Milo eats a cup of food 268 calories and gets a few table scraps. I can believe my estimate of an active 10 pound cat outdoors needing 600 Calories. 60 Calories per pound. In Metric that 600kcal /4.54 kg = 132 cal /gram for an active cat outdoors.
Let’s compare that with @Coloma ‘s horse. Call it 20Mcal per day for a horse weighing 500kg (1100lb) = 40 cal/gram for an adult non-working horse.

Let’s do it for a human. 2200C or 2200kcal for 150 pound 68 kg person. 32 cal/gram for a human sitting on his butt much of the day, indoors.

This is great stuff. Thank you all !!! Am I off base here? Surely there is a study.

I seem to remember that the key consideration is the ratio of the animal’s surface area to its body mass. Of course there are insulating factors like fur, blubber and down. But creatures like shrews and hummingbirds are right at the engineering border line. To be warm blooded, their metabolisms are so high, that their caloric demands dictate lives as perpetual eating machines. As animals increase in size there’s greater mass to surface area and therefore a larger “core” area in which to store heat.

The relationship of metabolic rate to body mass is a power law, with the exponent somewhere around ¾. Historically (as Kleiber’s Law), it was thought to be ⅔, due to the geometry of the overall body shape of the animal (as @stanleybmanly just mentioned), but empirically, the exponent is actually closer to ¾. I think the current hypothesis is that this relates to the increase in volume of branching networks (because blood flow limits nutrient transport).

(Milo, at about 13+ years old, is now considered a sernior citizen, and his daily caloric intake reflects that. Two years ago vet suggested we cut back from his then 360 calories per day plus table scraps to the leaner diet.)

edit: senior

Domestic animals have had quite a bit of research done on caloric needs.

Wildlife, less so

But I’m not able to find a general calculation based on body volum.

edit: Oh, wait, Kleiber’s Law is what you want. (Oops, dappled leaves already found that.)

@dappled_leaves I wish I could give more than one GA!
If we only consider heat loss I can see how the rate could be ⅔ exponent since volume (mass) goes up as the 3 power of length while surface are goes up with the 2nd power or square. But It can’t gbe just that since we need to take into account the extra mass the animal needs to haul around. That pushies it up closer to linear.

Anyway this tells me that one squirrel every 2 -3 days is just what the cat needs. Therefore it is likely I am the only person feeding it. Darn it. Now I have a responsibility to keep it up.

This also tells me that the neighborhood coywolf pack, assume 6 at 25 kg each, will need to eat about 90 calories per gram each, which translates to 2.25Mcal each or x 6 = 13.5Mcal for the pack. That means the pack needs 13.5Mcal / day. A 110 pound deer 50 kg, is worth 50kg x ½×7kcal/gm = 175Mcal or about 1 good sized deer every 13 days.
@syz I was typing this when I saw that you just replied. I will post this anyway and see if my numbers match the info you just sent.

@LuckyGuy Arctic wolf (in the North American wildlife chart) would seem to be the closest kin to your coywolf, but that’s a pretty big stretch.

(My training was mostly for cattle in ag classes, but that was many, many years ago. When I was working with exotics, the big cats got whole carcass, and monitoring their weight was sufficient. But the diet calculations for the carnivores that also ate fruit was more complex.)

(This is why I am still hanging out here rather than cleaning my refrigerator. Milo has a metabolism 32 times that of an average mouse, apparently. Is that why he wins most of the time, rather than by cunning and deviousness?)

@syz I LOVE THAT CHART!!!!

I will assume the 25 kg coywolf is close to a 50 pound dog. The chart shows 720 Calories, 720kcal x 4.0 for active working dog = ~3000 kcal per day = 3.0Mcal each. I calculated 2.25 each above! Wow! That is very close!!!
So I can expect to have one deer taken down every 2 weeks to keep those demons from consuming a 150 pound person carrying a Thanksgiving turkey carcass out in the woods at night as an offering to a fox family.

<—- Buying more ammunition.

The square-cube law does have an effect, though it’s a bit weird.

Smaller animals have more surface area compared to their volume, so they radiate heat quickly. Conversely, larger animals have more volume and relatively less surface area, so they conserve more heat. In fact, that is part of why elephants have those ears; heat sinks.

Of course, that assumes all is equal, which isn’t always true; shape matters. Elephants are a different shape than, say, a coyote, so they aren’t directly comparable.

This also tells me that my estimate of the nutritional content of squirrel, mice, etc. is not that far off.

@jerv Yep! That is exactly how I looked at it, and the numbers seem to fit. The active, 10 pound hunting cat needs 132 cal/gram, while the scary 50 pound coywolf takes 90 cal/gm. And the fat*ss human needs only 32cal/gram. Physics works!

@gailcalled I suspect that the nutrition / labeling information on the packaging is incorrect. As evidence, I point to the following spelling and syntax errors in the copy:
Hill’s Prescription Diet t/d Feline Dental Health Dry Food:
Larger-sized kibble that keeps your cats teeth clean
Controls oral bacteria found in plague
Reduces bad breath, stain and tartar buildup as well as plague
Promotes a healthy immune system
Complete and balanced nutrition

Calorie Content: 268 kcal/cup

In both instances above, the word “plague” should be “plaque”. The word “cats” should be “cat’s”. In view of these obvious copy errors, untouched by any proofreader, I believe that the calorie content of “268 kcal / cup” should be 268 calories per cup, which would still make it a very calorie-dense food. On the other hand, at 268 kcal per cup, you could use it as an effective boiler fuel – and the seller could not afford to sell it as cheaply as they do.

@CWOTUS @ragingloli got it right. We here in the US use the units Calories or Food Calories, e.g. a can of tuna, yellowfin, packed in water, 6 oz, is 112 Calories. The rest of the world would call it 112kcal. Sometimes we call a Calorie a Large Calorie to mean 1000 kcal. If we just switched over to metric all this nonsense would go away. But, no, people are afraid of the word kilo – it sounds European/foreign. We’re Muricans! Everyone else should switch to match us. Burma and Liberia are the only other two powerhouses that still use the English system so we are in good company. Oh… wait… .

I’m guessing the copywriter of the label on Milo’s food is not an English speaker. Either way the 268 Calories or 268 kcal is likely correct.

@LuckyGuy
this video sums it up perfectly

@ragingloli Thank you for clearing that up. Incredible.
My favorite is the ‘unit of weight’ called the grain – gr. No, not gram. Oh no. That would be too easy. What the heck is a grain? It is 1/7000 of a pound . It is based on the average mass of a seed of a barley and wheat. Really! They use it for measuring bullet and projectile weight. As in “that segmented subsonic round is 40gr.”
Meanwhile I have to convert everything to g so I can do real physics.
Burma and Liberia. Sheesh!

Last week the deer hunter covering my orchard counted 15 deer of all sizes. That means the coywolves will easily have enough food to last the winter.

The great answers here have taught me that one way or the other the cat should get about 120–150 grams (¼ pound) of meat per day. I’ll make sure it does not go hungry.

@LuckyGuy Be generous, and don’t for get the occasional can of real tuna.
I should have you do the math on my 22 lb. cat who is pretty lazy but not overweight, just big and long and furry.

Milo here; my beverage of choice is tuna juice; the solid meat doesn’t interest me at all.

@Coloma It would be difficult for me to be that generous. Heck, I don’t even treat myself with a can of tuna. But, now I have a reason.

I can leave a forkful and pour the juice on a squirrel.

^^^ LOL tuna basted squirrel.

^ No doubt a much appreciated delicacy!

@Coloma I ran the numbers based upon Milo’s 13 pounds. All things being equal your 22 pound cat should consume 1.48x what Milo eats.

Confused – are you feeding a pet, or the wild animals in the adjacent forest?

@dappled_leaves Long answer to a short question.
I do not like to waste food and often put out table scraps for critters to enjoy. I have an area well away from the house that is on the edge of woods Nearby is a pile of logs where I place about a coffee can full of bird seed food daily and occasionally some bread. Birds love it and I have some great pictures of all kinds.
My home also borders on a wildlife preserve across the street.

This area has been plagued blessed with a tremendous number of squirrels, chipmunks, and mice illegally dropped off in the wildlife preserve across the street by neighboring suburbanites armed with Havahart traps who think nothing of foisting their problems on others. (Don’t get me started.)
After ‘enjoying’ the sounds of squirrels in the attic, chewed wires in cars, damaged bird feeders, nests in farm equipment, destroyed bird nests, etc., a couple of the neighbors decided we would work on finally controlling the situation. And after a year of concerted effort, we have, and things are near normal.
In the interval I had been putting the carcasses out near my wood pile. Every night the carcasses would disappear without a trace. I set up a stealth/trail camera to record the nightly visitors and have taken pictures of fox, racoon, opossum, turkey vultures, skunks, coyote…. and a coywolf!
Recently a cat has started to show up and eat the squirrels I leave out for the other animals. While the other animals always take the carcass away, the cat leaves it in place and eats it over a period of 2 – 3 days. That got me thinking of how much it eats, if it is being fed elsewhere, and that got me thinking about all the other animals in the woods.
My apple orchard is visited daily by as many as 15 deer.. Also a pack of coyote or coywolves haunts the area. Their chorus of howls sounds like something from a horror movie. They are scarily well organized and sneaky. I’ve used a thermal imager and have watched them watch me at night when I put out an offering. They are so stealthy and always try to get behind me as I move through the woods. Interesting.
This question got me wondering how much they eat.
The engineer in me took over and I then wondered about the mathematical relationship… and so it goes.
I have learned a lot today. That’s why I love this place.

Well, cats are descendants of desert-dwellers, so their digestion is a bit more efficient than many other mammals. In fact, they can survive solely on meat without any need for additional water. As a side-effect, their waste is a bit more concentrated.

@LuckyGuy I’m sure that the cat is eating elsewhere in addition to your squirrel offerings. One squirrel over 2–3 days is not much, especially for an outdoor or feral cat.

I read a book many years ago about the red wolves in Algonquin Park (which are wolf-coyote hybrids, if we can take that term seriously), and the authors mentioned behaviour much like what you’ve described. People go to Algonquin to “howl at the wolves” on guided tours, and while the researchers were there, they would sometimes watch the wolves with thermal imagers to see their behaviour in such encounters. Typically, a few wolves would do their howling performance from the front, while others would circle around quietly, and watch the humans from behind, unseen.

I live in major Mtn. Lion territory, and have only seen one in 23 years, but, I have no doubt they see me all the time. I actually stumbled across a cached deer carcass once on a walk down my old road in the hills here. I was new to the area and at first thought it was a poached deer. Later I realized I had come across a Lion cache.

Scary..I wouldn’t be a bit surprised if that cat was nearby. ” Hey big kitty, no worries I don’t want your deer.” lol

@dappled_leaves The coyote are small, unorganized, and afraid of humans. Everything a coywolf is not. My neighbor weighed one and said it was over 50 pounds.
I cannot easily see them with night vision like deer who just stand there in the woods thinking they are unseen. These devils split up and circle around hiding behind trees. The thermal imager (borrowed from the lab) shows where they leaned against a tree or where they were crouching as well as their heat signature. When you walk along the trail they fan out with one to stop your progress and a couple moving silently behind. Turn around and the rear guard quickly moves behind a tree. Creepy. (He says, sliding the safety from S to F.)
They are coming from the North in Canada and supposedly have extended their range to the NY- Pennsylvania border in the Southern Tie, 75 to 100 miles south of here.
I wonder how many pets have mysteriously disappeared.

@Coloma And a Mountain Lion is even worse! Yikes!

@LuckyGuy Well… creepy or awesome, depending on your perspective. ;)

Unless you are a toddler, I’m sure you’re perfectly safe unarmed. Mountain lions are a totally different story.