Mischievous

So I visited the Barnes Wetlands Centre today for Joe's birthday (which is actually tomorrow) with Joe's family.
There were three otters that lived there and they were being soo playful with their keepers.
As a Zoologist I know tons of useless animal facts so here we go:

Did you know that otters hold each others hands before they go to sleep so they don't lose each other while they sleep?

Well now you do! :)