Did you know that pets are required to have passports too? I only just learned about this. My friend, who is in the process of relocating abroad, and is bringing her beloved dog with her, just informed me that this is a real thing. I guess it makes sense, but not being a pet owner myself, it's not something that I have ever really thought about.
This new learning prompted many questions: Where does one obtain a pet passport? Does the dog have to go into a drugstore and have a passport photo taken? How long are pet passports valid for?
With piqued intrigue, I decided to do a bit of research. It turns out there is a system, in Europe, called 'PETS' cleverly enough (Pet Travel Scheme). PETS allows animals to travel easily between member countries without undergoing quarantine. The conditions of admittance are twofold: 1) Surgically implant a microchip in your pet and 2) Get a pet passport (an official registration document that details vaccinations and other necessary veterinary treatments).
The rules for bringing a pet into the USA seem to be very strict and vary by animal. If you're interested, you can read more about these rules here.
It appears that there is no real standardized process for travelling with pets overseas. As specific requirements are different for each country, it is wise to request pet travel information from the local consulate/embassy of the country where you and your pet will be travelling, to ensure the pet will be granted entry.
Oh, and to answer some of my silly questions from above...
You get a pet passport from your vet
The photo is optional and it does not have to be taken professionally
Pet passports are generally valid for 2-3 years, but that can vary