Why does a dog lift its legs to urinate?

Legend 1: Emperor Taizong of the Tang Dynasty took a pair of dogs to Huashan Mountain to offer sacrifices to heaven. In the middle of the sacrifice, the female dog suddenly became impatient and ran to a tree to solve the problem. This kind of disrespectful behavior annoyed the Jade Emperor. The Jade Emperor ordered Lei Gong to hit a thunder, which hit the tree and killed the female dog. The male dog was very scared. From then on, the male dog would stretch out one foot every time he peed under the tree to hold the tree hard to prevent it from falling down and crushing himself to death.

legend 2: in order to punish a bully, Ji Gong covered his leg with copper coins, and then sawed off the Butler’s leg and installed it for him. He installed a dog’s hind leg for the housekeeper, and squeezed a false leg for the dog with mud. Since then, when the dog urinates, he will lift the mud leg, and bullies will be called “dogleg”. This story was read when I was a child.

and the scientific explanation is that it is a natural territorial behavior for dogs to lift their hind legs to urinate. In order to excrete urine higher and farther, the territory is marked by smell. Therefore, most dogs that raise their legs to urinate are adult male dogs, but about a quarter of female dogs will lift a hind leg when urinating, but the action is not the same as that of male dogs.

the urine of animals is not only the function of excreting body waste, but also has a kind of pheromone, which has the function of communication. From the pheromone, we can judge the age, gender, body shape, physical condition and other information of the urinator, and remind the opponent that “I am very strong and healthy, don’t intrude into my territory”. Therefore, it is very common for animals to use urine to mark their territory.

when a dog was a child, both male and female would squat and urinate. At about 89 months old, the male dog will begin to lift one of its hind legs when it shoots urine. The raised legs are stiff and straight, and the body forms an angle so that urine can be shot to the side rather than down to the ground below. Male dogs have a strong desire to raise their legs to urinate. Even if their bladder is completely empty, they will continue to lift their legs. There are three reasons why male dogs should lift their legs to urinate.

the first is to keep the odor signal fresh as far as possible and increase its duration. If the odor signal is placed on the ground, it is easy to be polluted, and it can be kept longer when placed in a vertical position.

second, lifting legs to urinate can move the odor trace to the nose height of other dogs, which is easier to be smelled by other dogs. Tell other dogs that this is their territory and do not intrude into it.

third, it also reminds the urinator where the odor information is. We can observe that when the dog urinates, it does not run directly to raise its legs, but sniffs carefully to see if there is any mark of its own, so the use of vertical markers helps to find out quickly.

the researchers found that in some cases, “urination height” can accurately reflect the body size of the urinator, but it is not suitable for small dogs. Small dogs seem to deliberately increase the angle of raising their legs, leaving higher urine marks and pretending to be large dogs to “confuse” their opponents and avoid conflict. Therefore, small dogs like Bago will urinate in the “big top” position to make up for the lack of body shape.
it’s different from the way dogs raise their hind legs when they urinate. When a female dog raises her legs, one of her hind legs is lifted up and moved under her body rather than straight to the side. So its urine will still fall on the ground. Sometimes they take an ugly handstand position, walk backward and climb up a pole or wall, then urinate with their legs in the air. The reason for female dogs to raise their legs to urinate may be territorial consciousness, imitation of male dogs, attraction to male dogs, and cleanliness habit, which are normal behaviors.