I've 2 almost six year old poodle/spaniel mix males .They have always slept in the kitchen and were in a crate at night until this year ,when we switched to a baby gate across the door. Now one has learnt to lever the squeeze both side and lift handle on the gate. I presume with his teeth . It must take some effort and determination .He is barely the height of the gate on his hind legs.
Now I get visitors around 3am !