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Science Notes

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Science Notes

Biomes

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Science Notes

Biomes

Lessons

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Science Notes

Biomes

Lessons

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Science Notes

Biomes

Lessons

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Science Notes

Biomes

Lessons

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Science Notes

Biomes

Lessons

Some Animal Weights
and Caloric Requirements on Earth

How to Use These Charts:

• 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