The second thing that depends on the first is to understand the basic comparative anatomy, most animals, especially mammals, have the same "pieces" only of different sizes (this is also true for humans).  Animals that belong to the same group or family usually have the same general body divisions, but the stretch and thickness of these divisions are different.  For example, the body of a horse and a bear are both composed of three main parts: front, middle and end, but the dimensions of these parts are very different in these two animals, and therefore a lot of eye training is needed.
Also, physical characteristics such as the shape of the animal's head, body shape, tail length, size of legs and neck, etc. are known in studying and seeing the animal's body well.
The third point is that when you look closely at the animals, you will fully understand with which geometric shape each animal can be drawn on paper.  At this point, you need to make the forms simpler.  With this method, you can easily understand how to draw animals such as horses, dogs, bears and others.
I will tell you this explanation with a simple example, suppose you want to draw the snout of an animal like a dog, you should know that such an organ can be drawn with the geometric shape of a triangle.  Or different parts of the body can be represented by a circle or an oval.
The fourth point in animal painting is to divide the body into parts.  Most of the livestocks can be divided into six main areas: 1- head, 2- neck, 3- front legs and shoulders, 4- middle part of the body, 5- back legs and buttocks and 6- tail.  This may sound like a simple observation, but once you break the animal in this way, you can overlap those areas in space from any direction.
The fifth point is to create a primary sketch somewhat according to the above points and without details.  Let your hand go free and use simple lines and geometric shapes to draw on the animal's primary sketch.  In the next steps, add details to the sketch and correct the curves and details.
The sixth point is that when you have several subjects in the image, use the overlap of shapes in space to create depth, observing this point is effective in creating distance and proximity of subjects.  Proper overlap of shapes will give your paintings a sense of believability and life.

Content Source:

https://www.skillshare.com/classes/Animal-Drawing-Draw-and-Sketch-Animal-with-Pencil/624785676