I just tamed my first one and realized it has unlimited stamina, I was running around and found Dilo, it kept attacking me so I gave it a poke in the eye with the thumbs, it said I could lvl up my iguanidon, then I saw that I could upgrade stamina..... so I did
I was playing on the island map, and I got a high level one that I named Iggy. After some leveling Iggy was at level 203. I had a Ptera, but Iffy was way better. I went away for a bit, and when I came back to base I got the message: "Your Iggy - Level 203 has been killed by a Dilo - Level 100"
I went full speed back, and I sicked all of my tames on that Dilo. Since then, I have played on two different maps. Each time, when I see an Iguanadon, I check the level immediately. They are so hard to find. I did find a 120, but it got killed by a Carno.
So 10/10 would tame again. Assuming they don't get killed by a lowly dilo while its on passive...