by any chance

[Do228]

What can you say when you see a dachshund who's only 30cm long?

You're .............. the tiniest dachshund I've ever seen.

by any chance
mayhaps
peradventure
conceivably

 

[probus]

Only conceivably works.

It's best not to use who in reference to animals. A dachshund only 30 cm or which is only 30 cm are both better than a dachshund who's.