Kneecap slipping out of place (much more likely); Corneal ulcers (more likely)7,8
Kneecap slipping out of place (much more likely); Underactive thyroid (more likely)7,9
Class
Lap dog
Lap dog
Which suits you
Size
The Chihuahua comes in a wide range of sizes, 1–3 kg (2.2–6.6 lb) as an adult, against 1.4–3.2 kg (3–7 lb) for the Pomeranian.
Temperament
They differ most on independence (Chihuahua: decides for itself; Pomeranian: cooperative, with its own ideas) and on handler demand (Chihuahua: needs steady training; Pomeranian: suits a first-time owner).
Alike
Both are rated the same on activity: happy with modest walks.
Neither is the better dog in general. Which suits you depends on your home, your days and the care you can give.
Breed explains only about 9% of how individual dogs differ in behaviour10. Meet the dog. A good breeder breeds for temperament as well as health, and matches each puppy's personality to the right home11,12.
Puppy growth
Reference curves · both sexes
Summary
Detail
The Pomeranian grows to the heavier adult, about 2.3 kg against the Chihuahua's 2 kg.
Expected weight in kilograms, both sexes: each breed's adult weight grown along the under 6.5 kg band of a WALTHAM growth standard13 and the under 6.5 kg band of a WALTHAM growth standard13.
O'Neill et al., 2022. Frequency, breed predispositions and other demographic risk factors for diagnosis of hypothyroidism in dogs under primary veterinary care in the UK. CC BY 4.0. ↑