Dogs roll in poop mainly due to instinctual behavior inherited from their wild ancestors, wolves. This behavior, known as scent rolling, serves several purposes:

• Communication : By rolling in poop, dogs impart their own scent onto the smelly substance, signaling to other dogs "I was here." It's a way of marking territory and sharing information within their social group. This is linked to their use of scent glands and urine marking for communication.
• Camouflage : Rolling in strong smells like poop can mask their own natural scent. This likely helped wild ancestors hide their presence from prey and potential predators, enhancing their ability to hunt and survive.
• Scent Sharing and Sensory Enjoyment : Dogs may also roll in feces or other strong odors to gather scent information about other animals or places. Additionally, some dogs might find the sensation pleasurable and experience it as sensory enrichment.
• Stress Relief : In some cases, rolling in poop may serve to relieve stress or anxiety in dogs.

Though revolting to humans, this is normal and natural dog behavior rooted in evolutionary survival tactics and social communication.