Background information Edit
"Like shepherds, from planet still in stage of raising great herds of beasts. But their society is technologically sophisticated. They have certain powers of telekinesis. Can transport selves mentally. Have mental communication with all animals on all planets. Have been imported into Earth system to take care of animals, fish, and bird life. Really 23rd-century ecologists. Little bags hung around them are for food – pellets which they mix with water to produce a yeastlike food." (The Making of Star Trek: The Motion Picture, p. 130)
"Though their clothing belies the fact, these people come from a socially primitive but technologically sophisticated society. For planetary transportation they rely on the powers of telekinesis but for space travel they employ seemingly crude vessels which they power with their minds. In the 23rd century ecologists do exist and the Kazarites are the ultimate masters of the profession – they are able to communicate with all forms of animal life on all planets within the sphere of Federation influence. Because of this they have been imported into the Earth system to handle the care and communication of all known as well as any new forms of life discovered. These peace-loving galactic veterinarys are vegetarians by nature and the small bags they carry with them contain food pellets which produce a yeast-like food when mixed with water." 
In part two of "The Star Trek Costumes" – published in the March 1980 edition of Fantastic Films, – Fletcher revealed information about the Kazarites and the design of their costumes, commenting, "I felt they should look sort of like an otherworldly shepherd. So the material is very sort of homespun looking."
An article appearing in the January 2002 edition of Star Trek: The Magazine Volume 2, Issue 9, entitled "Who is that Alien?", light-heartedly characterized the Kazarites as "the Dr. Dolittles of the Federation" and suggested that the reason the Kazarites devoted much of their time to caring for animals was "presumably because they enjoyed the conversations."