Human ears can&#x27;t hear ultrasound. What about other animals[1] on this planet? 
[1]<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Ultrasound#Animals" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Ultrasound#Animals</a>