An example of similar usage appears in this excerpt from Richard Rupp, Death & Taxes (2015):
It was a little after seven-thirty in the evening when Dick's flight landed at Lackland Air Force Base, just west of San Antonio. The Gulfstream pulled up to a hangar, where a sister FBI Gulfstream was parked. The aircraft's stairs were lowered, and Dick was directed into the adjacent hangar. Waiting for him in an office was the rest of his team, who had arrived an hour ahead of him.
“Hello, Animals! Good to see you.”
Daniel asked, “Why are we at this air force base?”
“Because this is where we catch our flight to Mexico City.”
Here the character Dick uses Animals as an affectionate, highly informal name for his colleagues just before they embark on a secret mission. The usage resembles the habit that some people (in the United States) have of calling their friends "dawgs." The term is not intended as an insult; it's spoken in a tone of comfortable familiarity. Be that as it may, "Hi, animals" is by no means a common way to address friends or colleagues in the United Sates.