Hi there! Thanks for sharing. I suggest focusing on one animal at a time. So that the construction can be really evaluated. Once you learn one animal the next one will be easier since it may be just a few shifts in proportion but the same building blocks. If you enjoy drawing animals using videos along with photos is helpful. It helps give a sense of movement, character, and weight.

Hey Henrique, I like these sketches, they really show the personality of the animals. I suggest you draw animals the same way you would humans: gesture, and structure. Structure is important with animals because we can get caught up in their details and flatten our drawings. If we make sure all the main masses of their bodies are working 3 dimensionally as well as in perspective, things become a little easier. I did a quick sketch over your horse drawing to show you what I mean, I hope it helps :)

First thing I would say is try to make sure photos are in focus and with even lighting so the drawings are nice and clear. I think you have really good proportions and forms, I would try to work on line weight so they're not so dark all over, then add heavier lines for important focus areas or overlapping forms, etc.