Crawler cultivated tartan leeks (11)

I believe the answer is:

rattlesnake

I'm a little stuck... Click here to teach me more about this clue!

'crawler' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.

'cultivated tartan leeks' is the wordplay.
'cultivated' indicates an anagram.
'tartan'+'leeks'='tartanleeks'
'tartanleeks' is an anagram of 'RATTLESNAKE'.

Can you help me to learn more?

(Other definitions for rattlesnake that I've seen before include "Heavy-bodied American pit viper" , "Creepy type" , "Virulent type" , "Venomous creature" , "Serpent with noisy tail" .)

I've seen this clue in The Mirror.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.