Usually between six months and a year old, but it is different for each dog.
The smaller breeds of dogs tend to have their first estrus cycle at an earlier age, while the large and giant breeds of dogs may not come into heat for the first time until they reach eighteen months to two years of age
As a rule, Dogs come in 'HEAT' twice a year. They generally can have puppies after they are 1 year old, and every year after that. One litter a year usually. It is recommended that dogs don't get pregnant the first time they come in Heat.
A female's first season is usually before she is a year old. Thereafter she usually has a season every 6-7 months unless pregnant or spayed. If you do not have a purebred, registered dog with titles and ancestors with titles, please spay her. There is no need for BYB (back yard bred) dogs which are only slightly better off than puppy mill dogs. Additionally, it is very unpleasant living with a female in season. She gets cranky and or airheaded. She leaves blood drops all over. She smells. She attracts stray dogs. It's just plain best to avoid the whole mess.
That might have been the wolf because the wolf are ancestors to the dogs.
where did the guide dogs start
about 6 months, and every 6 months after that until the age it goes through the menopause
Female dogs usually come into season every 6 months but it can vary from dog to dog.
The smaller breeds of dogs tend to have their first estrus cycle at an earlier age, while the large and giant breeds of dogs may not come into heat for the first time until they reach eighteen months to two years of age
Most dogs come into season approximately every six months (twice a year) but for some dogs it can be one to four times a year.
Yes, Dogs come into season between 6-12 months of their first year. So this time is very normal.
6 months. They should be spayed or neutered by this time to prevent additional complications during surgery, if you choose to do so.
they first start eating when they have their teeth fully grown out
Dogs will start to show during their first month of pregnancy. Dogs will often nest when they are close to their due date. Watching the dog's behavior is key.
The female dogs come in to season or heat twice a year. Each season last fiive to 10 days.
Most dogs come into season/heat every six months for 10-14 days. Your dog will start bleeding and will repeatedly lick itself. Dogs are often very touchy and react out of character at this time. Some dogs will become more aggressive to other dogs at this time also.
The girl puppies will start acting strange then the boy dogys will start to follow them  and the girl dogs whine and the boy dogs grunt so that's how u know
Mammoths were living before wolves were domesticated into dogs.