Опять коллизия со спирсовским словарём идиом.

У вас в словаре Proverbs:
Look like the cat who swallowed the canary
Знает кошка, чьё мясо съела.

В словаре R. A. Spears. NTC's American Idioms Dictionary:
look like the cat who swallowed the canary
to appear as if one had just had a great succes.
After the meeting John looked like the cat that swallowed the canary. I knew he must have been a success.

Согласитесь, разница огромная.