How come dinosaurs like the titanosaur grow to such large size, when animals like the elephant cant grow larger due to the square cube law?

Question

As far as i know, there arent bigger animals around today due to the square-cube law, and yet their were dinosaurs the size of whales on land?

In: 906

Answer 1

I am not going so much into the square cube law, as this is explained by others.

As for why dinosaurs grew so big but land mammals don’t grow to enormous sizes, this is likely due to dinosaurs having a lot of traits that allowed it.

1) They likely had an air-sack based respiratory system like their offspring (modern birds). This is significantly more efficient them mammal lungs and the efficiency decays way less with neck size. (The air-sack system is also why modern birds can perform labour intensive flights in high altitudes)

2) For the most part, they did not posses specialized teeth, but instead relied heavily on their stomach. There is a theory that scaling up helped here.

3) Their bones where likely lighter and already carried the adaption for bipedal walking.