3 ms·T Rex lifespan of what, 10-20 years? That’s a tiny number - about 3 TRexes in the entire country of Belgiumby midasuni 6y agoT Rex lifespan of what, 10-20 years? That’s a tiny number - about 3 TRexes in the entire country of Belgiumrightbyte 6y agoImagine how much land you need to support one T rex though given how big they were.ksaj 6y agoAgreed. It's the one thing we know for sure about the ocean and its rather large predators.