I highly recommend counting on being dragged off by one of these guys, stay away from the water even on a tall mount, the lower you go, the higher the chances of you being knocked off your mount and dragged off into the water. Have a sword or bolas, I usually go with the sword option as you can just go on to kill it immediately.
The higher your Melee the better your chances of killing them with little damage taken. I've fought them off easier with the sword.
Avoid Dinos that are low to the ground cause they will snatch right off... Just avoid the swamps until you have the appropriate equipment and armor to deal with Dinos in the swamp. These guys are worse than Sarcos.
This guy is my favourite so far, right from when I first meet him, I was a noob and wandered close to a swamp well he came flying at me missed and disappeared behind me, I'm like what the neck was that, climbed a big arse rock asap and looked around, bugger came bounding back towards me and leapt straight up that rock like it was a mole hill.
Tamed the bugger and took him hunting, came across my first raptor and shat myself thinking oh rap I am screwed, nope Kappa flys over my head, collects the raptor and pile drives it into the ground several meters away, hilarious. Always fun times with Kappa around.