Mostly I call the baby triceratops because I think it's a fun word to say but it reminds me of a really cute family story. When my Mom was pregnant with my youngest brother my brother Nate was about 6 years old or so. As a kid he was reallly into dinosaurs and he would ask my mom repeatedly if she could have a dinosaur instead of a baby. I remember my mom looking at him very seriously and saying "Even if I try my hardest I can't have a dinosaur."
And Nate replied "I know you can do it Mommy! You can have a dinosaur and we can name him furball."
Instead we got Wes. I think it's been working out okay for us. :)