The phrase "pack animals" refers to certain kinds of animals, like wolves or dogs, that live and work together in a group called a pack. They help each other to survive and complete tasks. Full definition
Dogs are naturally inclined to work well in social environments, as they are pack animals by nature. (club-penguin.org)
Cats are not pack animals with a social system like dogs and in nature, adult cats live solitary lives with no need for companionship. (helpsavepets.org)
They are social pack animals who need the freedom to roam in their own safe spaces. (onegreenplanet.org)