While it may sound like laughter to human ears, it could be any of a wide range of sounds that animals, particularly members of the Canidae family - dogs, wolves, foxes, jackals, etc. - are capable of making.
"Canidae have a lot of vocalizations," Crosby explains. "After all, we have the 'laughing hyena.' So who's to say this isn't analog to our laughter? He seems to be having fun."
And that's the most vital distinction here. An animal who looks like he's having fun may make sounds - and those sounds might fairly be considered sounds of joy.
Or, as we humans like to say, laughter.