If you’ll be patient, you’ll soon follow my logic. When biologists and paleontologists first discovered Dinosaur fossils, they naturally assumed from the size and shape of the jaws and the size of their bones, that they must be the ancestors of reptilians, specifically Crocodilians. They even coined the phrase “Dinosaur”, which means “Terrible Lizard”! This was a complete logical fallacy, making massive errors with regards to correlation. What we have subsequently discovered, is that their bone density, hip structures, and the fact that we’re discovering feather imprints in the fossil remains, that they have a lot more in common with birds.
A fundamental difference between Reptiles and Birds is that the Reptilian group are Ectotherms(Cold-Blooded) and the Birds are Endotherms (Warm-Blooded). Ectotherms rely on external factors to regulate body temperature. An easily observable example is that of Crocodiles lying in the sun to heat themselves up, and when they overheat, they return to the water to cool themselves again. Endotherms have built-in structures, like the thyroid gland, fur or feathers, brown and white adipose tissue, and sweat-glands to give them more control of temperature regulation. You’ll notice the larger an animal grows, the greater their adaptation to getting rid of heat. For instance, the large ears of an elephant are perfectly adapted to getting rid of heat. If you compare ancient Mammoth and Mastodon that lived during the last Ice Age on the Mammoth Steppes, whose ears were relatively small, and bodies covered in a downy fur, with modern elephants, who have no fur, and whose ears are significantly larger, you will notice the patterns adaptation to heat. An Indian Elephant’s weight maxes out at around 5000kg, and an African Elephant maxes out at around 6000kg. It is interesting to note that even though the African Elephant is only about 15% larger, their ears are around 200% larger, which would seem like a huge overcompensation until you adopt the SA/V Ratio (Surface Area to Volume Ratio).
The SA/V Ratio states as objects swell in size (increase in volume), their surface area does not increase the same amount as the relative increase in volume. This causes heat retention problems, meaning that they cannot get rid of heat or retain heat too easily, which is the reason they have evolved sophisticated heat liberating mechanisms, like sweat-glands, feathers, sweat-glands etc. Now if a 6000kg Elephant has thermoregulation problems, even being warm-blooded, imagine an estimated 35000 – 45000kg Brachiosaurus? For a Brachiosaurus to be cold-blooded goes against all laws of physics, so Occam’s razor, which states that the simplest theory must suffice- they were warm-blooded. Now relate this information to body fat and overactive thyroids. When one gains weight, and especially if it’s a lot of weight, you’re decreasing your SA/V Ratio and increasing your thermal barrier, which makes it much harder for your body to get rid of heat and thermoregulate. In this case, your Thyroid has no option but to down-regulate, which in turn becomes a self-fulfilling prophecy for the fatties! Should you wonder if your Thyroid is functioning properly, take your body temperature, if it’s between 36.3 and 36.7 degrees Celsius, then it’s doing its primary job of Thermoregulation properly. If it didn’t do this, you’d be in a constant fever state, which is lethal to humans. You simply don’t get to defy the laws of physics!