How to get the second string in the ORA-02296 error to show something meaningful

Whenever I run the following script*:

ALTER TABLE ANIMAL.MONKEY MODIFY TAIL_COUNT NOT NULL;

I receive the following error:

ORA-02296: cannot enable (ANIMAL.) – null values found

I have a script that modifies a large number of tables. It would be really helpful if the error message read:

ORA-02296: cannot enable (ANIMAL.MONKEY) – null values found

… or something else that identifies either the problem column or the table in which it resides.

ORA-02296 has the following detail about it:

ORA-02296 cannot enable (string.string) – null values found

Cause: Obvious

Action: an alter table enable constraint failed because the table contains values that do not satisfy the constraint.

This suggests there is a second string available somehow. How do I get the error to display more meaningful information?

*names have been changed to protect the innocent.