While not quite the same as human jealousy, cats can act out over perceived threats to resources and territory.
Territorial Roots
Negative behaviors like peeing, yowling, swatting, or knocking items off shelves may indicate a cat wants your focus.
Attention Seeking
Set aside daily segments devoted just to petting, treating and playing with your cat so they don't feel ignored.
Spending Time
Make sure to show affection to all pets/family members when together so one doesn't appear favored.
Affection
Duplicate resources like food bowls, litter boxes, scratchers and beds so cats don't have to compete.
Resources for All
Over time, give constant gentle affection and treats to help cats adjust to new family additions.
Patience and Love
If behaviors persist or worsen, speak to your vet or cat behaviorist for tailored advice.
Consult the Experts