Word for ascribing animal-like mentality to humans (opposite of anthropomorphize)

I'm wondering if there is a word that, essentially, means the opposite of anthropomorphize- roughly, assigning animal-like attributes or mentality to a human. Beastialize doesn't seem to fit the bill as it: a) doesn't seem to be a'real word' and b) is heavily associated with bestialism.

I came across a good example of this in Bill Sapphire's 1993 ON LANGUAGE: Sic 'Em in which they were discussing the connotations of the phrase after Bob Dole used it in reference to other politicians:

When American Speech magazine queried readers about sic 'em in 1961, one observed that his mother heard it from Arkansas friends who owned hound dogs. Another reader, the great San Francisco dialexicographer Peter Tamony, replied: "The remark describes an unresponsive, indolent, shiftless person. He is like a dog that shows no courageous and instant reaction to the command 'sic 'em.' " Mr. Tamony gave an etymological insight by adding that sic 'em is "merely a pronunciation modification of seek 'em or seek 'im."

Solution 1:

I think OP makes too much of the connotations of bestiality (sexual relations between a human being and a lower animal). There's nothing wrong with...

bestialise/-ize - to make bestial or beastlike: War bestializes its participants.

Solution 2:

Zoomorphism

Zoomorphism is the shaping of something in animal form or terms. Examples include:

• Art that imagines humans as non-human animals
• Art that portrays one species of animal like another species of animal
• Art that creates patterns using animal imagery, or animal style
• Deities depicted in animal form, such as exist in ancient Egyptian religion
• Therianthropy: the ability to shapeshift into animal form[3]
• Attributing animal form or other animal characteristics to anything other than an animal; similar to but broader than anthropomorphism
• The tendency of viewing human behaviour in terms of the behaviour of animals, contrary to anthropomorphism, which views animal or non-animal behaviour in human terms

The word derives from the Greek ζωον (zōon), meaning animal, and μορφη (morphē), meaning shape or form.

Source: Wikipedia

Solution 3:

It isn't perfect but how about dehumanize?

Solution 4:

Consider theriomorphic. From Oxford Dictionaries:

the·ri·o·mor·phic /ˌθɪərɪə(ʊ)ˈmɔːfɪk/

(especially of a deity) having an animal form.
‘gods depicted in theriomorphic form’
‘a theriomorphic vehicle’