A dog is man’s (and woman’s) best friend, so obviously people need a day to celebrate canines -- especially puppies. March 23 is National Puppy Day 2015. Puppies are adorable to watch, but there are some things that you might not know about the animals besides from how to cuddle with the furry friends. To celebrate the holiday, below are 12 interesting facts about puppies.

1. Earlier is better: Dogs are known to become set in their ways, but puppies are open to new things. The best time to introduce them to new experiences such as socializing is between 3 weeks old and 12 weeks old, the American Society for the Prevention of Cruelty to Animals (ASPCA) reports.

2. Names: Max and Bella were the most popular names for new puppies in 2013 and 2014, according to “Today.”

3. Mother’s milk: Puppies don’t need to eat solid foods until they are 3 or 4 weeks old, according to the ASPCA. All of the nutrients they need can be found in their mother’s milk. If they don’t have access to their mom, contact your veterinarian to find out what would be the best replacement.

4. Anxiety: Sometimes a puppy can love their owner a little too much and develop separation anxiety. In order to make goodbyes as painless as possible, leave quickly and provide a distraction such as a treat or a toy. If the separation is causing the pup to act out, leave it with a dog sitter or put it in a confined area such as a crate or playpen, Petfinder recommends.  

5. Puppy Bowl: Instead of watching the regular Super Bowl, audiences can tune in each year to the Puppy Bowl on Animal Planet. The pups play "football," and kittens provide the halftime entertainment.

6. Most popular pups: People love Labrador Retrievers. American Kennel Club has named it the most popular dog breed for 24 consecutive years.

7. Bathroom behavior: Puppies don’t know how to urinate or defecate by themselves. During their first few weeks, mothers will “instinctively stimulate their babies to excrete waste through licking,” according to the ASPCA.

8. Christmas puppies: While the idea of getting or giving a puppy on Christmas morning is adorable, make sure you know the risks. Puppies are expensive and time-consuming. People for the Ethical Treatment of Animals (PETA) recommends giving someone a gift certificate to adopt instead of surprising them with a furry friend.

9. Brothers and sisters: Puppies have plenty of siblings. Litters usually contain four to six puppies, the ASPCA states, and fertile mothers typically produce one litter per year.

10. Puppies born daily: There are roughly 70,000 puppies and kittens born every day in the U.S., according to PETA.

11. Becoming a dog: You can call your dog a puppy forever, but by medical standards, they’re only a puppy for so long. Puppies can reach adulthood at any point between six months and three years depending on the breed and sex, the Daily Puppy reports.

12. Dog Day: The pups will still have a holiday after they hit adulthood. National Dog Day is Aug. 26.