However, another member of our family never volunteered for the whole foreign exchange process.

Cholula, our aging black lab.

Over the years, our house has developed a strange routine. A stranger arrives with suitcases, an unfamiliar scent, and an entire life temporarily packed into one bedroom. Months later, that same stranger leaves, having become part of our family. Cholula has experienced that cycle right alongside us.

She doesn't understand student visas, cultural differences, school registrations, or why these strange teenagers keep appearing and then disappearing. She simply knows that, every so often, someone new comes through the door. And eventually, they leave.

Cholula has a wonderful ability to make her part in all of this rather simple. We handle the paperwork, school registration, transportation, scheduling, planning activities, cooking endless meals, and the never-ending laundry. Cholula helps someone adjust to an entirely different country. She lets them scratch her head or rub her belly. She gets a new person to cuddle with on the couch. She has someone new to take her on walks. She gains another person's crumbs to hunt for under the table. She has someone else to get excited about when they walk through the door after school.

And, in return, she asks almost nothing of them. She doesn't ask uncomfortable questions. She doesn't care if their English isn't perfect. She doesn't get frustrated when they don't understand something. She is simply there — a constant source of affection in a house, country, school, and culture that are all completely new.

Interestingly, none of our students had ever had a dog before coming to live with us, so Cholula has been a first experience for them, too. They learn her behaviors, her routines, and her personality. And each of them seems to develop a slightly different relationship with their host sister.

One decided it was perfectly acceptable to let her lick him on the mouth. EW! Another liked having her sleep in his bed during the cold Wisconsin months. One liked to roughhouse with her. And another enjoyed farting on her. Teenage boys are weird. Luckily, Cholula farted plenty back at him.

And Cholula does her job as the big sister. One of the first things she does in the morning is check their bedroom doors. Did they get up for school? Are they still sleeping? Should someone wake them up? Can I go in there and cuddle? She greets them at the door when they return from a grueling day at school. She waits for attention, follows them through the house, and stands guard in the hallway. Somehow, she has even learned that she isn't supposed to go into their bedrooms unless they invite her.

But eventually, that sad day always comes. One afternoon, nobody comes through the door around 3:00. And then nobody comes through the door the next afternoon. Or the next. For about two months, the house becomes quieter. Cholula seems a little sad during those months. Maybe she notices fewer people around. Maybe she wonders where everyone went. Maybe she simply notices that there are fewer hands scratching her ears and fewer crumbs mysteriously appearing on the floor.

I like to think that, by now, she understands the pattern. "It's okay. It won't be long until I get new siblings." And eventually, she does.

Luckily for Cholula, some of her past siblings have also come back to visit long after their exchange year ended. Interestingly, she doesn't seem nearly as excited to see them as she does when meeting a brand-new student.

I choose to believe that it isn't because she has forgotten them. I like to think it is because she hasn't. There is no need for the frantic excitement of meeting someone new. She already knows their scent, farts included. She already knows their voice. She already knows that they belong here. They're simply home again.