Is there a substantial difference between a pet cat and a pet dog?

Question

In Nethack, several roles by default start with a kitten or a small dog, chosen at random. They seem to be very similar: both have similar growth cycles and behaviors. Is there any substantial difference between them that is relevant to the gameplay? Do they behave differently, for example?

Answer 1

Kittens and little dogs are statistically identical, except for a few differences:

1. Kittens have the M2_WANDER property, which means they wander randomly.
2. Dogs are harder to tame at night during a full moon.
3. When they grow up, dogs become Medium size, but grown-up cats remain Small size. The only difference is possibly squeezing through narrow cracks, and that only Medium creatures can wear shirts and armour... which I don't think animals can anyway.
4. When they grow up, dogs weigh more than cats: 400 for a dog and 800 for a large dog, whereas the housecat weighs 200 and the large cat 250.
5. Dogs bark, cats mew.

(Source: Nethack Wiki, and Nethack 3.4.3 source code).