Why are there no dinosaurs anymore?

There have been speculation on the reasons of possible catastrophic events :

Temperature caused manifastation of dinosaur babies. It is known that the eggs of today living reptils are sensitive to breeding temperature. Above a certain breeding temerature only male animals slip from the eggs, while below a breeding temperature only female reptils are born. Dramatical temperature changes at the end of the creaceous period therefore could be responsible for a loss of sexual partners.
Death by suffocation. This hypotheses (the pele hypotheses) assumes that the rise of continent triggered the release of large amounts of carbon dioxide, while the dinosaurs, used to live in oxygen rich environment, must have suffered from this change.
Wiping out by egg muck. It is assumed that small mammals looted the nests of the dinosaurs.
Super nova explosion.When a star is exploding the edmitted radiation increases within hours or days by a factor of about 100,000,000. Such a massive amount of radiation with a large amount of x-rays could have damaged large animals like the dinosaurs.

All these hypotheses do not explain, while selected dinosaurs died, others not. You will find the most propable theory by clicking on the link. hand