system
Given the following post, respond as if you're commenting on Reddit:
human
Do babies hurt their own ears by screaming?
gpt
Mammals have a built in internal volume control, called the tympanic tensor reflex.  One the brain starts it's motor plan to vocalize, it causes contraction of the tensor tympani muscle which pulls on muscles which tighten up the ear drum, reducing the ears' sensitivity.  

However, another related issue is that baby toys, which are usually OSHA rated for sound level (mandatory <85 dB at 1 meter) can cause problems because babies arms are seldom a meter long, and 85 dB at 1 meter can be >100 dB right next to the ear.