Groaner

Aptly named due to the groaning sounds they make when startled or attacking, these monsters resemble canines which have rotting flesh and presumably have the accompanying smell of rot to boot. They have also been known by the more technical name of "Canine Monster Type A".

In terms of Dog species, they closely resemble are the English Greyhound, albeit with a larger mouth and sharper teeth. They share some of the sighthound characteristics of the greyhound also as they will actively seek out anything near them that makes a sound to see what it is. If it is living, they will attack. It's most likely that they live in perpetual torment and that no morsel of food will sate their hunger.

As they tend to be found outdoors, Harry Mason can use his broken radio to detect whenever there is a Groaner in his vicinity as it will start to hum static in a specific fashion. However, if spotted by one it is best to try to run away as they are extremely agile and are difficult to hit with a weapon. Their main form of attacks are biting with their powerful jaws and lunging at their prey.

If one is killed by Harry, it's best to double-check they are truly dead by stomping on their bodies. As it's possible for them to simply be stunned and get back up to resume an attack.

In terms of their symbolism, it's most likely that they represent Alessa Gillespie's hatred and fear of dogs. Their emaciated appearance may be because she wishes them to be unsatisfied.

Interestingly the Groaner seems to resemble a Zombie Dog from the Resident Evil series with milky-white eyes et-al. Albeit the flesh necrosis isn't anywhere near as bad.