what does this mean?

[mack]

I have trouble understanding the phrase 'BRING ON YOUR SABERTOOTHS', which I came across in a SF novel in which a hippie-like group demands that the government should send them back to the Miocene by a time machine. They demonstrate in front of White House with placards which say 'BACK TO THE MIOCENE', 'LET US LEAVE THIS LOUSY WORLD' and 'BRING ON YOUR SABERTOOTHS'. Sabertooth is an anmal supposed to have existed in Miocene.
I found the expression 'BRING ON YOUR BEARS' on Oxford English Dictionary. Does 'BRING ON YOUR SABERTOOTHS' basically mean the same thing: 'do your worst (but we won't give up the hope of going back to the Miocene)'? I am totally confused.

[Billyum]

I have trouble understanding the phrase 'BRING ON YOUR SABERTOOTHS', which I came across in a SF novel in which a hippie-like group demands that the government should send them back to the Miocene by a time machine. They demonstrate in front of White House with placards which say 'BACK TO THE MIOCENE', 'LET US LEAVE THIS LOUSY WORLD' and 'BRING ON YOUR SABERTOOTHS'. Sabertooth is an anmal supposed to have existed in Miocene.
I found the expression 'BRING ON YOUR BEARS' on Oxford English Dictionary. Does 'BRING ON YOUR SABERTOOTHS' basically mean the same thing: 'do your worst (but we won't give up the hope of going back to the Miocene)'? I am totally confused.

"bring sth on" means give me that challenge. In this situation it means "send us back to the past", "let us face the challenge of the sabertooths".

Example: A: Mack, you have to teach a 40 student English class. It'll be tough

Mack: No problem, bring it on, I can do it!