I was low level when I got mine (On single player too) it was always around the river I used for water and kept breaking my pipes. So I looked at a few guides and found an easy way to capture it. Just build a 3 x 3 of stone and build 3 stone door frames up on each side. On another build ramps going up to the top. Get the attention of the spino with your weapon (a bow will do) and run up the ramps, it might take a few tries but if it follows you slip through the door frame and it won’t be able to escape, then just knock it out with tranq arrows or darts. Hope this helps. Good Luck :)

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