They do that off and on throughout the series. For example, there are some that run like that in Issue 7.
Homedragon
2019-06-07 03:14:34 +0000 UTC
Niixa might have stopped Endy, but the spirit of revenge seems set to burn everything down. I'm guessing this isn't what she had in mind and this is why she was warned not to attack first. I do wonder if this is part of Muroku's plan?
Silver Huskey
2019-06-07 02:26:57 +0000 UTC
So some of them are built for going around on all fours? Neat. (This is the first time I’ve noticed it, at least.)