What is Smaug's resting heart rate?

Added: 2026-06-03

[00:00:00]A lot of you guys have been asking me what Smaug's resting heart rate is, so I thought I'd talk about it. This is a dragon biology case study the cardiology community has frankly not given enough attention. While Tolkien did not give us Smaug's specific dimensions, we can base this video's analysis off of The Hobbit movies. Weta Digital, the New Zealand VFX studio that designed and built Smaug for Peter Jackson's Hobbit film, published official measurements which put Smaug at 130 m long with a 110 m wingspan, which makes him twice the size of a jumbo jet. His mass is estimated to be somewhere between 12,000 and 60,000 tons. This is a big range to work with, but conservatively this means he is at least 80 blue whales in size.

[00:00:48]Kleiber's law says that heart rate scales inversely with the size of a creature to the fourth power. An untrained adult might have a heart rate of 70 beats per minute, while an African elephant sits around 30, and a blue whale sits around four to eight beats per minute. The second important thing to know is that a reptilian metabolic baseline is an order of magnitude lower than the equivalent mammal. The final detail that's worth mentioning is that Smaug was asleep for 171 years before Bilbo woke him. This is known as extended torpor, which would mean that his heart rate would be pushed even lower after waking up. Combining all of this with Kleiber's law alone, we would get somewhere between two to four beats per minute. If we add in his reptilian characteristics, this would push it down below one beat per minute. Finally, if we include extended torpor, we can safely say that Smaug's resting heart rate after he awoke would be somewhere between 18 to 48 beats per hour.