No, not often...
giraffidae means giraffes
If you mean "What are giraffes scared of?" the answer is: All the carnivorous animals that hunt it for food; lions, leopards, hyenas and wild dogs.
Depends on what you mean by "biggest", but, no. Plenty of animals that are heavier and wider. But measured from the ground and up, giraffes are the tallest.
no never eat other Giraffes.
Yes, giraffes do have knees.
Giraffes can get harmed
No. Giraffes are herbivores.
Giraffes
WE do not understand what you mean by "clement" in the context of your question. "clement" means "mild".
A giraffes movement is walking
Giraffes are mammals.