This is why America is great...we're home to the world's only ultrasonic squirrels:

A species of squirrel uses ultrasonic frequencies to warn fellow members of its group of impending danger, the first time an animal has been found to use high-frequency sound this way, said a study published in the weekly journal Nature.

The unusual rodent is a Richardson's ground squirrel (Spermophilus richardsonii), which makes its home in the prairies of North America.

...

The finding is of interest because it is the first time an animal has been found to use ultrasonic frequencies for communication. Other animals, such as bats and dolphins, use ultrasonic frequencies to locate obstacles or pursue prey.

Now if we could only weaponize them...