Rats fled US at variance (8)

I believe the answer is:

defaults

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'rats' is the definition.
Although both the answer and definition are verbs in their -s form, I don't understand how they can define each other.

'fled us at variance' is the wordplay.
'variance' is an anagram indicator.
'fled'+'us'+'at'='fledusat'
'fledusat' anagrammed gives 'DEFAULTS'.

Can you help me to learn more?

(Another definition for defaults that I've seen is " Fails to fulfil obligation or to appear".)

I've seen this clue in The Globe and Mail.

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