Dogs may have been man’s best friend — and treated as such— since the earliest days of domestication.

According to a study published recently in the Journal of Archaeological Science, prehistoric people likely cared for a sick puppy for weeks before it died, suggesting an emotional attachment to the animal.

Member of the Pack

In 1914, workers uncovered a grave at Oberkassel, today a suburb of Bonn, Germany. The remains — a dog, a man, and woman, along with several decorated objects made from antler, bone, and teeth — date back to the Paleolithic era, around 14,000 years ago.

View Images Telltale signs on the puppy's teeth show that it likely contracted canine distemper at about 19 weeks old. Photograph Courtesy Martin Pütz

It is the oldest known grave where humans and dogs were buried together and provides some of the earliest evidence of domestication.

Now, new analyses show this puppy was not only domesticated, it also appears to have been well cared for.

In examining the remains, veterinarian and Leiden University PhD candidate Luc Janssens noticed problems with the teeth that had not been previously reported.

“I’m lucky because I am both a veterinarian and an archaeologist,” says Janssens. “Archaeologists aren’t always looking for evidence of disease or thinking about the clinical implications, but as a vet, I have had a lot of experience looking for these things in modern dogs.”

The puppy was about 28 weeks old when it died. Telltale signs on the animal’s teeth revealed it probably contracted canine distemper virus at about 19 weeks old, and may have suffered two or three periods of serious illness lasting five to six weeks.

Dogs: (Prehistoric) Man's Best Friend WATCH: Recently discovered graves suggest that humans loved and cared for dogs even in prehistoric times. Courtesy the University of Alberta.

Early symptoms of distemper include fever, not eating, dehydration, lethargy, diarrhea, and vomiting. Neurological signs like seizures can occur during the third week.

“Since distemper is a life-threatening sickness with very high mortality rates, the dog must have been perniciously ill between the ages of 19 and 23 weeks,” says Liane Giemsch, paper co-author and curator at the Archäologisches Museum Frankfurt. “It probably could only have survived thanks to intensive and long-lasting human care and nursing.”

This might have included keeping the puppy warm and clean and providing it with water and food. Without this care, the authors conclude, the puppy would not have survived.

Prehistoric Pets

The exact time and place where dogs were first domesticated is unknown.

“On the basis of current data, which is not fantastically copious, it’s clear we had domestic dogs by at least 15,000 years ago,” says Keith Dobney, an archaeologist at the University of Liverpool who was not involved in the study. “How much earlier domestic dogs existed is up for debate, with some people saying they might go back to 30,000 years ago.”

Human motivation for domesticating dogs is also not fully understood. Most theories revolve around the many uses humans have for dogs, like hunting, guarding, and herding. But the remains of the Bonn-Oberkassel dog hint at more.

“We suggest that at least some Paleolithic humans regarded some of their dogs not merely materialistically, in terms of their utilitarian value, but already had a strong emotional bond with these animals,” says Giemsch.

Janssen, Giemsch and their colleagues say this puppy represents the earliest known evidence of dogs being regarded and treated as pets (a domesticated animal kept for pleasure rather than utility). The care it received while it was ill and of no use to people appears to have been driven by compassion or empathy; in other words, an emotional bond.

“For me, it’s not a real surprise,” says Matthijs van Kolfschoten, an archaeologist at Leiden University who was not involved in the study. “I grew up on a farm with animals all around, and with all these animals you had emotional bonds. If you work or live closely with animals, you have this bond.”

That this dog was treated with such care tells us more about human behavior than anything else, says Dobney.

“The evidence suggests this dog must have been special to somebody, and that these kinds of emotional relationships existed 14,000 years ago,” says Dobney.

It seems that ever since wolves became dogs, humans have been suffering from a case of puppy love.