One dog attacked another and tried to kill him They have been together for 6 years never aggressive before He is old so know what think Is he getting senile or could it be rabies?

It is possible that your dog's behavior is due to senility, rabies, or another underlying medical condition. It is important to take your dog to a veterinarian as soon as possible for evaluation and diagnosis. If the attack was unprovoked and your dog has never shown aggression before, it is important to rule out any potential medical causes. Rabies is a deadly virus that can cause aggression and other neurological symptoms in animals, so it is important to be cautious and seek medical attention if you suspect your dog may be infected. Your veterinarian can perform tests to determine the cause of your dog's behavior and provide appropriate treatment.