User blog comment:Lord Loss/Monster Hunter Theory... Blog/@comment-74.193.210.169-20120703025110/@comment-4775842-20120813175707

Then perhaps monsters such as monoblos and gravios continue to grow with age. Instead of being active predators though, they could hibernate for hundreds of years under the lava or sand. This may actually be a hardwired system to make sure the species does not overpopulate. When the monster reaches a certain size, it eats as much as it can then digs deep underground or hides itself in the deepest of lava, and just sits there until it dies. Their body size would eventually kill them, either because their bones become too weak to support the weight, or of a lack of food. Therefore, the only alternative to extend their life is to burrow beneath the earth and wait to die. The giant skulls would then be evnetually found by carapaceons to be used as shells.

Humans also have a type of population limiter. This would be our slow rate of reproduction. Normally in the wild, most humans would manage to live only to thirty, due to both predation and the plaque and other diseases in our teeth. Those diseases would cause our teeth to fall out and/or the plaque build up would eventually enter the bloodstream and cause heart attacks. Modern medicine and hygiene protocols are the reason we live as long as we do, and humans would never have discovered these things if our brains had not exponentially increased in size over the course of several hundred thousand years.