Fang It to Me: Twilight Maths

November 24, 2009

Twilight, Stephanie Meyers vampire- romance book and film series, is a world phenomenon. Seventeen year old HIgh School student, Isabella “Bella” Swan, falls in love with Edward Cullen (Left), a vampire. But the Cullen family are ethical vampires. Though attracted to human blood; they live on the ethical alternative of animal blood. So here is the question mathspigs:

‘How much animal blood does a young male Vampire need to survive? 

First we’ll collect some data. We’ll assume Edward needs the same daily intake of calories as a young human male. According to the Free Library Online article, Best Food for Young Athletes, young males between 14 – 18 years of age need 3,200 Calories per day. We’ll assume Edward needs 3,000 Calories a day.

 How many Calories in Blood?

 The Mayoclinic explains that 1 pint of human blood contains 650 Calories. So if you donate a pint of blood you lose 650 calories. Blood donation is not, however, a desirable weight loss program. If Edward drank human blood he would need

3,000/ 650 =  4.6 pints a day.

Note: There is great confusion on the Web about calories as the upper case ‘C’ stands for kilo in USA and is often ignored:

1 Calorie = 1 kilocalorie = 1,000 calories

 But Edward has a taste for Mountain Lions (Below).  How many Mountain Lions would he need to suck on a day??????? Dr Carlisle Cullen (Right), on the other hand, prefers deer. While Emmett Cullen has a taste for the blood of Gizzly Bears(Below). As Edward, Carlisle and Emmett cannot always sink their fangs into their favourite furry food here  is some information about a range of possible Vampire Snacks.

Mountain Lion

Weight Range 75 – 275 lbs = 34 – 125 kg

Mid range Weight = 80kg


Gizzly Bear  Male

Weight Range = 180 – 360 kg

Mid range weight = 170kg


Weight Range = 100 – 350 lbs = 45 -160 kg

Mid range weight approx = 100 kg

Barn Owl

Weight = 0.45 kg


Weight Range = 1,500 lbs = approx 680 kg

Mid range weight approx = 100 kg

Shih Tzu

Weight Range = 9 – 16 lb = 4 – 7.2 kg

mid weight = approx 5.5 kg

Fat Cat

Weight = 18 lbs = 8 kg


Weight range = 7.5 – 11 kg

Mid range weight = approx 9 kg

Note: In the following calculations we will use a mid range weight for each animal snack and assume Edward can suck out it’s entire blood supply.  So Edward can empty an ocelot or koala (He might visit Australia one day and he’d be hungry!!!!) The weight of blood (Bwt)in an animal is 7% of the Animal’s Body Weight (Awt). This information comes from Animal Physiology Maths Questions. . Keep in mind if the answer is less than 1 the snack will last Edward several days. You can work out how many…… think about it.


Weight = 10.5 kg


Weight = 12.7 kg

Alright Mathspig will tell you the typical weight of a pig with great reluctance. It is 110kg. But just to wet your appetite here is a little Vampire Snack I prepared earlier.

Edward would need to consume 13 Chihuahuas a day.

Run, Tinkerbelle, run!!! (That’s Paris Hilton’s dog)


  1. […] Edward Cullen and the other Vampires in the Cullen Covern are ethical Vampires. (See earlier post: Fang it to me! : Twilight Maths) The only eat animal blood. Edward falls in love with Bella a human. The baddie Vampires are James, […]

  2. The math is good but some facts need fixing. First, the Mayo Clinic value for calories per pint is high. The correct answer is more like 425/pint. Search on “calories human blood” to see the math. Second, calories per pint is different across species. A lower RBC content of blood means lower calories. Third, Edward is dead, so he has no basal metabolic rate AND his movements are magically powered, not calorie dependent. So human caloric needs cannot be projected onto vampires.

    • Hey David,
      I lerv arguing about Vampires. If your calorie stats are more accurate than the Mayo clinic then students will have to substitute your figure. The biggest error I found research this topic was the confusion between Cal and Kcal. In fact, most stats are in Kcal. Finally, Edward may be dead but he eats the blood of Mountain Lions etc. I like to think of him as a strong healthy ex-human on a balanced Vampire Diet. Thanks for your Comments. Adds to the fun. Cheers Mathspig

  3. mathspig – Mayo clinic does not show their math. Mine does, and explains why not the same for males and females. I have seen the cal and kcal confusion trip up students who wonder why the energy it takes our body to warm cold beer up to body temperature is not greater than the calorie content of the beer.

  4. Thanks. See my latest posts especially 6 degrees of separation. Cheerio Mathspig

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: