I copied the knitting pattern out for anyone who is interested in it. It originally came from a Chihuhua rescue group.
I'm sure Zeus will love his sweater soon to be knit by your grandma.
here it is:
KNIT A CHI SWEATER
Back by popular demand! Knit your chihuahua a warm sweater this winter! Full instructions below!
(1) Sizes 5 & 7 knitting needles.
(2) Worsted wool, about 4 ounces.
(3) Measure your pet’s neck. I usually use a size 5 or 6 needle for a tightly knit ribbing (not too tight!). I cast on loosely, 40 or 42 stitches.
(4) Knit 1x1, or 2x2 ribbing for 3” for a mock neck, or 6” or 7” for a turtleneck.
(5) Change to a size 7 needle, and commence in the stitch or your choice. After you’ve knit one or two of these, you can see how easy it is to add cables, colour work, or other texture stitches in this back area. for the first one, let’s knit in my favorite basic stitch, garter. That is, knit every row! Can’t beat it for simplicity, stability, and rustic good looks.
(6) Measure the animal’s back length, that is, from the back of his neck, just above the shoulder, to the top of his tail. That’s how long you will knit straight, in garter stitch. That’s right! No shaping yet! When you have reached 2” short of the correct length, switch to size 5 needles, and knit 2” of the same rib you used for the neck. In garter stitch, this isn’t really necessary, but looks good, and if you use another stitch, it keeps the edge from curling. If you used another stitch, you should also have knit the first 4 stitches of every row, to keep the side edges from curling.
(7) Now, we will knit the chest piece. Using the size 5 needles, cast on 3 stitches. You will increase 2 stitches every other row, until you reach the width comparable to the distance between your pets’ front legs. You should increase 1 stitch, 2 stitches from each edge. The magic thing about this, is that it’s usually exactly the length you need to cover that tiny chest. It’s really amazing! Now for a male, knit straight until you get to1” shorter than where the ribcage stops, and add 1” of ribbing. Bind off. For a female, you can knit as long as the body of the sweater, to cover her bald little stomach (ending with 2” of ribbing, just like the back). Bind off. The reason I usually knit this piece on the smaller needles is, it has a tendency to get wet in the snow and stretch. A slightly smaller gauge helps. If you’re not using garter stitch, knit the first four stitches of every row.
(8) Seam the neck ribbing, remembering to seam halfway, and switch to the inside, if you’ve made a turtleneck. Now, place the point of the chest piece at the bottom of the neck rib seam, and sew a seam down both sides until you get to the point where you stopped increasing. Leave a slit for the front legs there, about 2” long, and continue the princess seams down each side. Tuck in your loose ends, wash and block carefully.
Note: experiment with your favorite stitches. I highly recommend using natural fibers like wool, alpaca, or cashmere.