Whenever there is an obvious change in how a dog is acting, one of the first things to look at is possible medical issues that may be causing the dog to act differently. Many conditions include behavioral changes, which can be interpreted as being moody as one of the symptoms. This includes:
In general, worms can make a dog act lethargic and this may be accompanied by a lack of appetite. This alone can make a Chihuahua seem depressed and not quite like himself. In the case of tapeworms, another symptom is restlessness; and therefore there may be mood swings of both feeling down and showing agitation. Other signs do include evidence of the worms in the stools, coughing, vomiting, possible changes to the skin or coat and in some cases, diarrhea.
Along with weight changes and skin changes, a Chihuahua with abnormal thyroid levels can behave very moody by displaying both signs of fearfulness and aggression.
Arthritis: When an older, senior dog gradually acts more moody, this can point to arthritis which worsens over time. A senior Chihuahua may have dealt with minor discomfort, but as the disease progresses, he is struggling more and having a hard time coping. Signs of this are difficult getting up from a down position, trouble going up or down steps, inability to keep up on walks as before and/or favoring a certain limb. Since arthritis is a degenerative disease, moodiness may gradually creep in.
Any medical condition ranging from allergies
to cancer all have the ability to rob a dog of his otherwise happy state can cause him to be moody. Any issue that makes a dog feel uncomfortable or suffer from discomfort will affect his moods. Dogs that are not feeling well will act down in the dumps, often retreating to be alone, will have trouble acting happy and some may show aggressiveness when approached.
Just a 1.5% loss of normal water levels in the body, which would be considered to be slight dehydration can cause several issues with a dog including loss of enthusiasm, being more tired that normal and a range of minor mood changes. For this possible issue, you'll want to access if your Chihuahua has been drinking enough water. Offering flavored ice cubes (water mixed with apple or orange juice) can help bring levels up to normal.
What to do:
Whenever there are severe mood changes, making sure that your Chihuahua has a full medical checkup is recommended. Even if your dog just recently had a vet visit, a health issue
could have developed from that time to now. The veterinarian should perform a full physical that includes examining all body parts, checking the ears, nose, eyes, throat and pulse, a complete blood count (CBC), urinalysis, thyroid hormone testing and usually a stool check (you will be asked to bring in a stool sample).
Many disorders are much easily treated when caught early and for some including heartworms, early detection is vital for successful recovery.
Chihuahuas can be very sensitive to changes in their environment and some do not cope well with certain circumstances. If your Chihuahua is moody in the sense that he seems depressed, is uninterested in playing and/or either retreats or acts overly clingy and all medical issues have been ruled out, you may want to take note of any changes that have happened in the home or the dog's social life.
Has a new family member either entered the home or left, either human or canine? Chihuahuas can become very sad if a person is no longer there every day or if another pet has passed away. And just the opposite, this breed often needs some time to get used to another person or another pet moving into the house.
Is a friend (neighbor's dog, a dog that the Chihuahua normally sees at the dog park, etc.) no longer available to play with? Missing a playmate can cause a dog to act moody and despondent.
Is the household more chaotic than normal? If there are loud arguments or even the element of a bunch of visitors in the house, etc., a change to a Chihuahua's normally peaceful day to one that seems more hectic can cause the dog to be moody. He may be restless and antsy and/or overly protective of his toys, food
and resting areas or the house in general.
Are you yourself more moody than normal? Dogs are amazing at picking up on the vibe of their owners and mimicking that. Certainly, you've noticed that if you are super happy and excited, your Chihuahua will act that way too. It works the opposite way as well. If an owner is under a lot of stress, upset about something or overly worried, it can cause a dog to display the same type of moods. Owners may not always realize that what they are feeling on the inside is being observed and noticed by their pets.
What to do:
If this is a matter of an issue that cannot be changed, such as a person no longer living at the house or a canine friend not being there anymore, in most cases the moodiness displayed will even out in time. It can help to distract the Chihuahua with an activity that is new to him. When feeling down, a Chihuahua may not want to play as normal or act enthusiastic about walks, but many dogs will perk up if a something new is introduced. This can be anything from a hike around a lake to working on some agility training with some fun obstacle hoops, weave poles or tunnels.
If this is a matter of there being some upheaval in the house, if at all possible work to resolve that issue. We can't expect our pets to act happy if humans in the house are yelling or creating commotion.
If you are experiencing some issues that are causing you to feel sad or upset, it may help to set aside even 30 minutes per day to 'purposefully' forget things and just have fun with your Chihuahua. Whether the two of you head out for a walk or play a game of hide n' seek, when you make an effort to spend quality time with your dog, it can help both of you feel better. If you take a look at things and realize that you may be expressing your anger or other negative feelings in front of your Chihuahua, he or she will be picking up on that. Working to speak to your dog in a happy tone (even if you have to fake it) and showing enthusiasm for all tasks ranging from grooming
to daily walks can help even out a dog's mood.
Hormonal Changes and Moodiness
Un-spayed female dogs can act moody during the heat cycle. Due to fluctuating hormones before the phase of discharge, during and even after as hormones are evening out again, a Chihuahua may have mood swings. This can include several emotions that may swing back and forth such as acting withdrawn, becoming insecure and wanting to stay close to the owner and/or some anxiety.
Since a Chihuahua will enter heat
twice per year and the cycle can last up to four weeks, if mood spells are coinciding with this schedule, this is often the cause.
In regard to males, un-neutered dogs may have brief mood swings of acting agitated if an female dog is nearby (you do not need to see her, he can sense her from very far away) as is unable to reach her.