Can dolphins and bats hear their own echolocation sonars

Can dogs or even humans pick up these sonars or would they be out of our frequency range?

Both Dolphins and bats hear their own echolocation sounds. Dolphins use their melons (gelatinous cavity in the front of their head) to intensify the sound and when bats and dolphins send out their sounds it reverberates off of foreign objects. Dogs and humans cannot naturally hear the echolocation sounds of dolphins and bats. However, many of those cellphone frequency modulators can emulate the same frequencies that those animals make.

If the dolphins/bats couldn't sense their own echolocation sounds, then why in the world would they use it?

They are out of our frequency range.