
Size doesn’t matter
Besides the obvious un-neutered and nurtured state, there’s not a lot of physical differences in a male and female dog. And size isn’t always an obvious clue. “Male dogs tend to be larger than female dogs, however, the exact size difference is dependent on the breed,” says Colleen-Demling Riley, certified dog trainer and canine behaviorist, Dogtopia. She points to the Yorkshire terrier for example. “The difference between a male and female Yorkie varies less than a pound, but a male Great Dane average weight is 130 to 200 pounds while their female counterpart averages 100 to 130 pounds.”

Girls mature faster
Female dogs reach puberty and adult weight faster than males dogs, which may play into their ability to pick up training commands. “A dog’s individual temperament will be the number one component that determines the ease of training, but, in general, female puppies tend to be easier to train,” says Riley. This doesn’t mean females are smarter than male dogs, it’s simply a matter of maturity. “The female is able to focus longer and learn tasks easier than her male counterparts of the same age.” Use the eagerness and focus a puppy and avoid making these training mistakes you’ll regret later on.

He has a nose for love
The effect of hormones on dog behavior hasn’t been studied in depth, especially in the United States where many dogs are spayed and neutered to control the pet population. Still, pet pros observe certain behaviors related to intact dogs (dogs that haven’t been neutered). “Male dogs have a biological imperative to procreate and this drive tends to supersede most other drives,” says Liz Claflin, certified dog trainer, director of operations for Zoom Room. You may notice your dog’s strong desire to sniff everything in sight during walks or when they suddenly drop the ball to investigate a scent. “Using their noses, dogs can smell another dog’s urine and learn a lot about that dog, including age, gender, and fertility,” Claflin says. “For a dog looking to make more puppies, this is critical data.” These are the best guard dog breeds.

She’s moody
While the effects of hormones haven’t been widely studied in dogs after they’ve been spayed or neutered, the behaviors seen in females and males in heat are well known. The American Veterinary Medical Association (AVMA) calls it “breeding instinct-related behavior”. And between the ages of six months to one year, a female who hasn’t been spayed will go into “heat” and display a bit of moodiness and physical symptoms such as vaginal discharge. She may be clingy and skittish or both during the 21 to 28-day cycle, which happens twice a year. Clingly or skittish, these are things your dog really wants from you.

She’s warming up
Females start to warm up to the idea of mating during the second stage of heat, called estrus. “As your dog moves into estrus, she may become very flirtatious around male dogs,” says Nick Hof, certified dog trainer and canine behaviorist of Paws Look Listen. And male dogs who are sniffing for clues pick up on her pheromones from miles away so if you’ve chosen to not spay, don’t let her out of your sight. “Keep your female away from other male dogs throughout this process as it may cause males to fight over her and some other females may be aggressive towards her as well,” advises Hof. Females hold their tail to the side when they are ready to mate. Learn how to decipher what else your dog’s tail is trying to say.

Male alterations
Intact males have some tendencies to mark (via urination) more frequently or diligently than neutered dogs, Hof says. Intact males are also keenly aware of intact females nearby and may be more prone to humping behaviors. These behaviors typically decrease when a male is neutered at a younger age. Usually, males are neutered at around six to nine months; waiting longer to neuter may not alter these behaviors. “A male who is altered at two years old has an established behavior that one altered at six months old would not have to the same extent,” says Hof. Here’s why your dog enjoys leaning on you.

Settling down
The AVMA says spaying and neutering curtail the breeding instinct in females and males. And for males, neutering can help your Casanova feel more like a homebody and not be so focused on roaming and escaping the backyard. Spaying and neutering also protect dogs from some serious health issues. The AVMA says spaying can protect against uterine infections and cancers such as breast, ovarian and cervical. For males, neutering helps protect against testicular cancer and enlarged prostate gland.

The social side of things
Early socialization is important regardless of gender. Taking your pup to meet and socialize with other people and dogs in various environments helps ward off aggression, fear, and timidness later on. That’s something to consider, Hof says, if neutering is delayed until later in life as dog parks, boarding facilities, and doggy daycares typically don’t allow unaltered dogs. Here’s why dogs freak out during thunderstorms.

Co-ed living
Socialization has a significant impact on whether two dogs can live in the same house, regardless of the gender of the dog. Still, Riley says dogs of the opposite sex tend to get along better, especially if they live together. Check out these dog breeds that don’t shed as much.

Nature of breeds
As with any dog, behavior traits are derived from pet parenting, individual temperament, training, and socialization, but Riley says sometimes subtle differences are seen between the sexes in some breeds. “The females of guarding breeds such as the Rottweiler tend to be gentler while the females of the herding breeds like the Australian cattle dog are less skittish,” Riley says. Here’s why dogs chase cats.

Some dogs are just more chill
A University of California Davis School of Veterinary Medicine study revealed that hormone levels of oxytocin (the “cuddle” hormone) and vasopressin (an antidiuretic hormone linked to heightened aggression in humans) influence canine social behavior and aggression too. Interestingly, service dogs, which are bred for their easy-going temperament had higher levels of oxytocin in their blood compared to average dogs. In contrast, dogs who were more aggressive towards other dogs had more vasopressin. What isn’t known is if vasopressin levels cause aggression or are the result of aggression, but at least there is an underlying base for the behavior for more research to be done. So maybe some behavior traits aren’t a matter of gender but of other factors like hormones and as canine behavior experts say, individual temperament, genetics, breeding, socialization, environment, and leadership of pet parents. Read on to learn the 30 things your dog wishes you knew.