There are two sizes available, which are accomplished by changing yarn size.

Sport weight/Adult large size
Needles: US 3 and 11
Gauge: 26 sts and 37 rounds in 4”
Yarns needed: less than 50g in each of 3 colors of sport weight yarn, plus less than 10g each of some yarn for duplicate stitching the face (depending on the critter: black, brown and optional white if you want the eye-sparkle). As well as about 100g of super bulky faux fur yarn such as Knit Picks Fable Fur.

If you like, you can use some light fingering held double instead of the sport weight, which is what is used in the sloth sample for the darker blue green.

Fingering weight/Adult Medium size
Needles: US 1 and 9
Gauge: 33 sts and 50 rounds in 4”
Yarns: less than 50g in each of 3 colors of fingering weight yarn, plus some for duplicate stitching the face (depending on the critter: black, brown and optional white if you want the eye-sparkle). about 100g of bulky faux fur yarn such as HIkoo Caribou.

You can choose to work different stripes, etc, which will require different amounts of yarn. I would look in my stash for scraps that are at least 30g for the most-used color and go down from there!