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 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