There are various reasons of course for hair loss.  But one of the reasons I’ve found is actually a thyroid disorder.  Thyroid disorders, if you have an overactive thyroid can overwork and overstress the systems whereas with an underactive thyroid, obviously some things are not being delivered quite correctly.  So either way, you could potentially suffer hair loss because of it.  The basic elemental difference is that with an overactive thyroid, you will be hot all the time, have a racing heart, have trouble keeping weight on with sudden weight loss, and otherwise while an underactive thyroid will be just the opposite. 

So it’s definitely something to keep in mind.  This can happen both in human and animal sufferers, and frankly it’s one thing to watch out for when an animal suddenly starts losing hair on their tail or something.  It can mean other things such as old age, allergies, etc.  But it can also of course mean a thyroid disorder, which is risky no matter the species.  If you have this problem however, you will of course know because hair loss won’t be your only problem at that point in time.