Is there an ldd or equivalent command in OS X unix?

I would like to find out what shareable libraries are linked to an app on my Mac. In HP unix or linux, I can do this with the ldd command. However, when I try that in Terminal on my Mac, I get:

-bash: ldd: command not found

I am perplexed by this. Am I missing the ldd program on my machine or is there a different command that will do the job?

Thanks,
Rich

EMAC G4 1.0 GHz Mac OS X (10.4.3)