Are we able to touch a fox, hyena, jackal or wolf? Are they classed as being of the dog family?
Initially, before explaining regarding those 4 animals which you mentioned, I ought to illustrate regarding dog and state how it is Najis; According to Islam:
It isn't impermissible(haram)to touch dog even though it is najis, so, the only way one’s hand becomes najis by touching them is if at least 1 of the 2 (hand or dog) has sufficient moisture for it to be transferred to other. But in case both surfaces are dry or only damp to the extent that no moisture is exchanged and transferred from one to the other, the hand or whatever else that has come in contact with the dog will not become najis.
Those four animals which you mentioned, actually Fox, Hyena, Jackal and Wolf have the same condition with Dog. e.g. look at the site below regarding the Hokm of Wolf (which has named the condition of wolf as the condition of dog):
Or for further info. regarding eating the meat of wild animals (such as fox, hyena,...), read the following text which has named different kinds of animals and actually it could be helpful for you :
Eating the meat of wild predatory animals that are predatory in essence, have strong and sharp nails, claws and fangs such as, lions, leopards, cheetahs, wolves, or animals with less sharper fangs such as, foxes and hyenas as well as rabbits, even though they are not part of the predatory category, are considered haram. Also insects and reptiles, such as snakes, mice, lizards, hedgehogs, fleas, lice, etc.; the examples for which are uncountable, are all haram. Animals who have undergone maskh (metamorphosis) such as, elephants, monkeys, bears, etc. are haram as well.
To see the detailed answer, please refer to the sources.