Not actually from Valerius Maximus...

[lesbiassparrow]

...but I do like to point out that Julius Caesar could believe batty things as well as the next Roman. For some obscure reason he believed that elks have no joints in their legs. This means that they have to stand all the time, because once they're down they can never get up. As a result they can only sleep standing up - and this is how you catch them. You sneak up on one as its sleeping, knock it over (I guess this is the ancient equivalent of cow-tipping) and it's powerless!