Puppies develop quicker, learn faster than humans

Danny Lopez, 7, of Hoffman Estates, is a soon-to-be second-grader at MacArthur Elementary in Hoffman Estates. He asks: "How do dogs have babies?"

Puppies are born the way Mother Nature designed: A seed fertilizes an egg and a baby grows inside the mother's uterus. A baby inside its mother's uterus is called a fetus. The time when puppies are born is called whelping.

Some breeds, like bulldogs, need help to reproduce. Veterinary reproduction specialists like Debra Sauberli at the University of Illinois College of Veterinary Medicine in Urbana provide expertise to guide the process. Sauberli's work also includes seeing dog and horse patients, teaching veterinary students how to care for animals and treating animal patients at the school's veterinary teaching hospital.

"Bulldogs would not breed without help from reproductive services. They usually need help with birthing," Sauberli said. That breed and others like it are large-shouldered and the babies cannot be delivered naturally. Whelping - natural birth - might harm the mother and the pups, so veterinarians perform surgery called a cesarean section.

Many mammal offspring are "singletons," being born only one a time. Dogs are different in that they give birth to many babies at a time.

"Dogs are pack animals," Sauberli said. "They hunt in packs. The more pups they have the better they fare and the more likely they will survive. Multiple fetuses helps perpetuate the species."

The way a dog's uterus is formed, in a "y" shape, allows it to nurture a number of unborn babies a one time.

"Sows are like dogs. They can bear litters of between 10 to 20," Sauberli said.

Both dogs and sows have multiple sets of nipples to feed their offspring. If there are a lot of babies in a litter, the offspring learn to take turns nursing.

Litter-bearing species have fetuses that develop quickly. For a dog, the gestation period, the time it takes for them to grow inside the uterus and be ready for birth, is a little over two months. Other litter bearing species like pigs are ready for birth at a little more than three months. Compare that to "singletons" like horses which need almost a full year to be ready for birth.

"Horses' digestive tracts can only handle milk protein for about two months and then they can be weaned exclusively onto adult type feed for adequate nutrition. Social development takes about four to six months," Sauberli said.

Puppies, on the other hand, nurse for about three weeks and then are weaned to solid food. Social development, the time they need to stay with their mothers so they learn about dog behavior, lasts about eight weeks.