World Builders: Caloric Requirements of Sample Terrestrial Animals E Viau CSULA

Decide how much the animal that you are designing weighs in pounds (or kilograms).
Decide if your animal is a hot blooded or cold blooded. (They have different charts)
Find the chart for your animal.
Go to the column labeled Weight in Pounds or Weight in Grams/Kilograms.
Look in this column for an animal that weighs about the same as your animal.
If you can't find one, go to the nearest weight and use math to get as close a guess as you can.
Go to the column marked KCalories Needed per Day to find how many food calories your animal needs. If you adjusted for weight, you will need to adjust here, too.
Go to Adjustments at the bottom of the page and adjust your numbers accordingly.

Warnings: I'm still working on the numbers here. There may be HUGE errors!

I have seen estimates that as much of 85% of a warm-blooded animal's energy intake is "burned" to keep the body warm. How much is actually used to supply warmth probably varies with the temperature ranges in the environment, but keeping the body at a steady temperature requires a lot of energy. Therefore warm-blooded animals have to eat much more than cold-blooded ones -- perhaps five times as much, maybe more. This is the major disadvantage to being warm-blooded.

There are advantages to being warm-blooded as well. Warm blooded animals can move quickly to pursue prey or evade predators. They can hunt at night, when many animals are asleep and temperatures are cool.

Small animals need more energy per ounce (or gram) of weight than larger ones do. A large animal has a lot of volume (inside) compared to its surface area (its outside), but a small animal has a lot of surface wrapped around a small volume of organs and muscles. (Review The Sizes of Living Things) This rule holds for both warm blooded and cold-blooded animals. It is even true for organisms too small for us to see!

Warm-Blooded Animals: Various Sizes

Animal	Weight in Pounds	Weight in Grams/ Kilograms	KCalories Needed per Day	KCalories /gram	Food contains __ KiloCalories/gram
mouse	.09 - 1.4	20-40 gm	10 - 20 Kcal	Food	3
hamster	.22	100 g	43
rat	.9	300-400 g	45 Kc		3
Guineau Pig	2.6	1200 g	105 ?
kiwi	3.9	1.8 Kg	776		meat/veg 3.2 KC g170 Kg
Rabbit	10	4.5 Kg	270		2
rabbit	14	6.5 Kg	430
cat	4.4	2 kg	175		3.5 Kc g
cat	8.8	4 Kg	350
cat	13	6Kg	525
dog	22	10 Kg	850	25-40 gm/Kg body weight	3.4 Kc/g
dog	44	20 Kg
dog	66.	30 Kg	4080 ?
husky sled dog not working	44	20 Kg	30 calories/lb of body weight
sprinting dog					2-3 times resting
distance runner dog					3-6 times resting
dog as mother					1 1/2 times at birth 30% of resting for each pup
Monkey	26.5	12 K		2-4% of body weight	3.2
Aardvark	121	55 K	706		meat -- 3.5 KCal/g
Gorilla	207	94 Kg	3394		fruit 2.9
Man	163	74	2550	2-4% of body weight	3
Woman	132	60	1940
Spectacled Bear	374	170 Kg	3072		general .7
Lion	397	180.5 Kg	7111		meat&bones1.8 KC
Pig	440	200 Kg		2-3% of body weight	3.16 Kc/g
Bottle-Nosed Dolphin	523	238	12404		fish 1.1 KC/g

Warm-Blooded Animals: Large Herbivores, Browsers and Grazers
Animal	Weight in Pounds	Weight in Grams/ Kilograms	KiloCalories Needed per Day	Do This: Choose body weight in Kg Multiply by 1000 to get weight in grams Multiply by .025 to get 2.5% of animal's weight Multiply by 1.3 Kcal per gram	Example: Goat weighs 40 KG 40 * 1000 =40,000 g 40,000 * .025=1000 1000 * 1.3 =1300 Kcal 1.3 is the number of Kcal in a gram of food.
Goat	88 lb	40 Kg	1,300
Sheep	150 lb	68 Kg	2,210
Sheep	200 lb	90 Kg	2,925
Cow	1000 lb	455 Kg	14,787
Horse	1500 lb	680 Kg	22,100 hard working horse 40,000

Larger Warm-blooded Herbivores				Numbers still uncertain
Giraffe	2600	1182	38,415 ?		plants 2.6 KC gm
Elephant	10,677	4853 Kg	12034?		plants 2.9 KC/g

Cold Blooded Animals

The caloric needs of cold blooded animals vary with temperature. If their bodies are warm they use more energy: if their bodies are cold they may be almost dormant and use very little energy. I cannot find much information on all this, and wonder if anyone really knows a lot about it. If you can help, please write!

Cold blooded vertebrates (animals with back bones) include fishes, amphibians, and reptiles.

Invertebrates (animals without back bones) such as insects, star fish, clams, etc are also cold blooded (ectotherms). So far I have found no mention of their caloric requirements anywhere, so we will just have to guess.

Cold Blooded Animals: Reptiles
Animal	Weight in Pounds	Weight in Grams/ Kilograms	KiloCalories Needed per Day	KCalories /gram	Food contains __ KiloCalories/gram
Garter Snake	1.7 oz	50g	8 Kc		5 g worms every other day @ 3Kc/gram
Colubrid snake	5.6 oz	200g	13 Kcal		30g mouse a week @ 3 KCal per gram
Boa/python	4.4 lb	2Kg	86 Kcal		a 200 g rat per week
Boa Constrictor	33 lb	15 Kg	333 Kcal /day		a 2Kg rabbit every 18 days
Monitor Lizard	35 lb	16 Kg	430 Kcal		5 rats a week

The animals for whom these caloric requirements were developed are pets, domestic, or zoo animals. They are not nearly as active as wild animals, who are hunting, foraging, and running from predators, so their caloric requirements are less than they would be in the wild.

Adjustments for Activity:

Activity Level

KiloCalories

Resting humans need one KiloCalorie per kilogram per hour
Let's figure out how many KiloCalories you need.

Say you weigh 150 pounds.

Divide by 2.2 to get 68 kilograms.

68 times 24 hours = 1632 KiloCalories per day to live

150 lb human
at rest

1632 KCalories

Light Activity add 50% to 70% of resting KiloCalorie needs
I chose 50%

Calculate 50% of the KiloCalories needed at rest
1632 * .5 = 816

Add resting Kilocalories needed for light activity total
1632 + 816 = 2448

Light Activity

2448 KiloCalories

Moderate Activity add 65% to 80% of resting KiloCalorie needs
I chose 70%

Calculate 70% of the KiloCalories needed at rest
1632 * .7 = 1142

Add resting Kilocalories needed to moderate activity total
1632 + 1142 = 2774

Moderate Activity

2774 KiloCalories

Heavy Activity add 90% to 120% of resting KiloCalorie needs
I chose 90%

Add 90% of the KiloCalories needed at rest

Calculate 90% of the KiloCalories needed at rest
1632 * .9 = 1468

Add resting Kilocalories needed to heavy activity total
1632 + 1468 = 3100

Heavy Activity

3100 KiloCalories

Very Heavy Activity add 120% or more
I choose 120%

Add 120% of the KiloCalories needed at rest

Calculate 120% of the KiloCalories needed at rest
1632 * 1.2 = 1958

Add resting Kilocalories needed to heavy activity total
1632 + 1958 = 3590

Very Heavy Activity

3590 KiloCalories

Notice that the working husky dogs, the working horse, and pregnant and nursing females all need more Kilocalories above the resting level. Most lab animals are living at a resting level: wild animals need more calories to deal with running around and temperature fluctuations.

Remember that the thinking here is probably sound, but the numbers are just guesses. Do the best that you can with your animals but don't stress out!

© 1999. Elizabeth Anne Viau. All rights reserved. This material may be used freely for instructional purposes but not sold for a price beyond the cost of reproduction. Please inform the author if you use it at eviau@earthlink.net