Thank you, Unclued. i was confused by all the posts apparently referring to separate words (? deliberate obfuscation) and especially sea snakes, garters etc. Sometimes one is too clever for one's own good! I agree that the final grid looks a mess.
Is that all we have to do? I have spent ages feeling stupid as I have been searching for actual snake names, resorting to anagrams and the like. I so hope someone says YES.
Rubric says drawn in the grid. I understand the relevance of the earlier post re snakes not having to cross. Also lack of artistry not a worry. Phew! How stupid of me to waste do much time.