A poodle in heat displays the same signs of estrus as any other dog breed, including vaginal discharge and swelling of the teats and vulva. Smaller dogs may not display these physical signs as prominently as larger dogs, in part because their smaller body parts make the changes less obvious.
A poodle in heat will also display behavioral signs that it is in heat. It will urinate more frequently, spreading its scent over a wide area to attract other dogs to mate. It may become restless or even aggressive due to huge fluctuations in hormones over the course of the heat cycle. In the later stages of heat, the poodle will initiate sexual contact by presenting its vulva to other dogs.