Few people know that up nearly 81 million years ago, a huge tyrannosaurs were the ancestors of the small and medium size. The remains of the youngest members of the family tyrannosaurids found rarely, and their age is estimated to be 150 million years. Researchers believe that such a rarity is associated with an increase in sea level, which flooded the continents and destroyed the bones and other traces of their existence. Fortunately, some of the skeletons still had not been flooded and destroyed — for example, the remains of two tyrannosaurs species Suskityrannus hazelae.
The bones were found at the bottom of the river Zuni, located in new Mexico. The ancestors of the huge tyrannosaurs was only one meter, and took an evolutionary position between the most ancient and young members of the species and all known carnivorous giants. The new discovery confirmed the theory that tyrannosaurs evolved from small dinosaurs and for some reason sharply increased and became bloodthirsty.
It is believed that small, medium and large tyrannosaurs had one, even more ancient ancestor, but his bones scientists are unlikely to ever be able to dig up. Meanwhile, the weight average ancestors reached 20-40 pounds, and they died in their Teens. It is considered that they are unlikely to become larger and heavier to achieve weight huge 7000-pound tyrannosaurs, they would have definitely failed. With all this, they were quite dangerous — the shape of the jaw suggests a high bite force.
The way tyrannosaurid so rapidly increased in height and weight, for scientists remains a mystery. Perhaps the secret as always lies in the climatic changes that can literally make animals become stronger and bloodthirsty.