One of my least favorite patients was a Chihuahua named Pedro. I had to respect him, he was close to 20 years old and still, shall we say, feisty. Toward the end of his life, I had hospitalized him for a chronic kidney condition when his family had to unexpectedly go out of town. He was on intravenous fluid therapy and needed frequent doses of his medications. I was uncomfortable leaving him overnight at the clinic (we weren’t a 24 hr facility and the nearest was several towns over), so with his owner’s approval I decided to bring him home with me.

Pedro was tiny. I got him comfortably ensconced in a small crate with bedding, food, and water and went to bed. When I woke up in the middle of the night to check on him, I found his IV line had kinked and wasn’t flowing. He bit me as I was getting things going again. Now, I don’t expect undying gratitude from my patients, but seriously dude? Here I am in my PJs tending to your needs (and not getting paid for it, I might add) and this is the thanks I get. Sheesh.

My experiences (there were others) with Pedro are just part of the reason why I don’t really consider myself a Chihuahua person. I’ve always thought of them as more designer dogs than the real thing. Turns out I’m either completely wrong or the “designer” in question lived in Mexico before the arrival of Europeans on the continent.

A recent study revealed pre-Columbian origins for the Chihuahua. It does not look like much genetic intermixing occurred with the dogs that subsequently emigrated from Europe either, making the modern Chihuahua remarkably similar to its pre-Columbian ancestors. This is especially interesting because, once Europeans arrived, native populations of both people and dogs were decimated by disease.

According to a report on National Public Radio about the study:

When he [Peter Savolainen, an evolutionary geneticist at the KTH-Royal Institute of Technology in Stockholm] and his team compared the sequences of the relatively unchanged breeds with those of 19 ancient dog sequences found across the two American continents, he was even more surprised. One breed — the Chihuahua — had a portion of DNA that was an exact match to that of an ancient dog.

"We have exactly the same unique DNA type in Mexico 1,000 years ago and in modern Chihuahua," Savolainen says. This suggests that at least this particular breed had genetic roots stretching back before the arrival of Europeans.

Savolainen goes on to say that breeds like the Chihuahua are a “remaining part of the indigenous cultures” and “that makes it more important that these populations … are preserved.”

Okay, I guess I’ll have to start giving Chihuahuas in general a bit more respect, but I still can’t help feeling that Pedro was a bit of an ingrate.

Dr. Jennifer Coates

Reference

Pre-Columbian origins of Native American dog breeds, with only limited replacement by European dogs, confirmed by mtDNA analysis. van Asch B, Zhang AB, Oskarsson MC, Klütsch CF, Amorim A, Savolainen P.

Proc Biol Sci. 2013 Sep 7;280(1766):20131142.

Image: Aaron Amat / Shutterstock