|Concept sketches of some baby monsters from The Legend of Red Dragon Ranch|
This is part of the focus on care in RDR. If you look at the illustration in this post, you'll notice at the top there are three dog-pup monsters and at the bottom there are four strange blob-like monsters.
These are not all different monsters--they are different appearances of the same monsters! The top row depicts Fen, a monstrous pup based on the legend of Fenrir. The bottom row is illustration of the slime monster Vitel, who resembles a cracked egg (the name Vitel comes from the Spanish 'vitelo').
When you first get a baby Fen, it will look like the Fen on the left. However, as you raise it, the way it looks will change. The way it changes depends on the way you take care of it. Since Fen is an active monster, the type of training it excels at will show in its appearance. The center image shows a Fen with a more muscular build, good at wrestling and sparring. If you spend a lot of time taking Fen to the gym, you might end up with a look like that. The image of Fen on the right, however, is a much more elegant Fen. If you spend a lot of time in the zen garden contemplating the meaning of life, for example, your Fen may look prettier, and its mind seed on its forehead will start to bud into a flower. All of these are still Fen, of course, just Fen looks a little different depending on how it is raised. It will not change in stat or nature or anything when these appearance changes take place.
Vitelo, on the other hand, is a more sensitive monster. Its appearance will change not based on what kind of training it practices or what facilities it uses. Its appearance is based on something else entirely. Can you guess what may cause these changes in its appearance?
The way your monster looks can also be a hint of what kind of adult it will grow up to be. While the looks of an adolescent Fen do not differ too wildly from a newborn Fen, and the same with Vitel, the adult forms will be quite different. An adult form of a monster is a completely different look, an evolution of sorts. Each monster has three different adult forms, and while the look of a monster can change many times while it's an adolescent, once it reaches adulthood it stays the same. So you can use the appearance of your adolescent as a guide to whether or not you are raising your monster properly, if you are shooting for a certain adult.
Of course, if you just want to play the game without aiming for certain kinds of training and just take care of the monsters however you feel like, you can do that, too! And you can enjoy seeing a variety of looks for the same monster as you raise it on your ranch.
A big part of The Legend of Red Dragon Ranch is that every player will have a unique experience, even though it will always take place at the same ranch. The way you build up your ranch, the monsters you raise there, how you take care of those monsters, what kinds of activities you focus on, and how you end up solving the mystery of the legend of the Red Dragon is all up to your personal playstyle. Having many different looks for a single monster helps with this 'unique experience' and allows you to experiment with the way you want to play the game.