Pet addendum - do I need all tenants to sign?

[Raman Bindlish]

All,

Looking from some feedback from experienced landlords who allow pets in the rental. I am adding a standard pet addendum and asking tenant to buy renters insurance which includes Pet damage and liability coverage. 

Now, there are 2 tenants and pet belongs to one of them. If the 2nd tenant does not want to sign on pet addendum, is there any issue? Can I just have one of them sign on pet addendum or I need to have both sign it?

Thanks

Raman