This attachment between animals and their owners is not always comparable to the human-animal bond. The human-animal alliance has been evolving for more than 15,000 years, according to Bayer, a life sciences corporation, and it began as a working partnership. People are protected and served by animals.

It could happen while hunting, farming, or performing other regular duties. Dogs sniffed and followed. Cats typically lived outside, hunting and killing rodents that could otherwise spread disease or harm food or other goods.

During the conflict, animals also served mankind. According to the United States Army Medical Department Journal (AMDJ), common historical military functions for animals include cavalry horses, security dogs, pigeons, and even mascots. According to AMDJ, these animals can bring stress alleviation and a sense of pride to their human partners in addition to protection.