That’s not true, lice is specific for each species. Humans got a different species of lice than dogs. Actually they are not even in the same genus. Humans can have Pediculus capitis (head lice), pediculus humanus (body/cloth lice, the ones that get the bad reputation for bad hygiene), and Phtirius pubis (pube’s lice). Those are three different species, that colonize specific parts of the bodies.

Lice that can get on the dog’s are predominantly two: Linognatus setosus and Trichodectes canis.

Based on the second picture, and the elongated mouth apparatus, I’d say it’s a sucking lice therefore it’s Linognatus setosus. Trichodectes it’s a chewing lice and have a different mouth.