Before exploring fur, color patterns or stylized clothing, every animal character, realistic or anthropomorphized, is born from a basic structure: anatomy, which defines its physique.
The body construction encompasses different species that have their respective anatomical characteristics and translating them into an anthropomorphic format requires a balance between fidelity to real biology and its adaptation. Therefore, the artist gains creative freedom with greater security, avoiding distortions that cause strangeness in the figures.
Within said principles of the anatomical structure of the groups of animals discussed, they include the skeleton, musculature and body covering of vertebrate and invertebrate animals. In addition to the ways of using body limbs and locomotion patterns.
Skeleton
The skeleton is the structural support of animals, which shapes the aspects of the body and its possibilities of movement and position. Whether the skeleton is internal or external, it determines proportions, balance, articulation points and biomechanical limits. It functions as a support and lever system for other components of the body.
Vertebrates
Although they have their differences, vertebrates have characteristics in common in their structures. They have an articulated internal skeleton composed of bones and cartilage, called the endoskeleton, which grows with the animal and defines the shape of the body and its different possibilities of movement depending on the species, in addition to providing support and protection for the internal organs. These animals have a skull, spine and spinal cord.
Invertebrates
Invertebrates, the structures can vary greatly. In general, they have a soft body, like mollusks, and depending on the organism they are also composed of a calcareous shell.
Ants, spiders and crabs have an external skeleton, called an exoskeleton, based on rigid external plates that cover and protect the entire body. It must be changed periodically (molting or ecdysis) to allow growth.
While the hydroskeleton is present in animals such as worms, jellyfish, starfish, earthworms and other invertebrates. It contributes to movement by pressure of internal liquids and uses longitudinal and circular muscles to generate displacement.
Musculature
The muscles are the engines of the animal body. They convert chemical energy into physical movement, allowing everything from the most subtle gestures to the most powerful movements. They give volume to the body and are specialized tissues that work together with the skeleton to generate force and are directly related to the method of locomotion.
Vertebrates
Vertebrates have muscles that work in coordination with their skeletons to assist in body support, movement, strength and stabilization of the joints, which are reinforced by tendons. They are composed of muscle fibers, which are grouped into organized bundles to allow efficient contractions. Different groups of vertebrates have specific muscular adaptations.
Invertebrates
The musculature of invertebrate animals presents varieties reflecting their evolutionary and ecological needs, from closing shells to flying.
These organisms with an exoskeleton or hydraulic pressure system have internal muscles attached to the carapace or joints. Without bones to act as leverage, movement is generated by changes in body shape or pressure from internal fluids.
In molluscs such as octopuses and squids, muscles contract directly to move the tentacles. They allow for extreme flexibility without a fixed bony structure.
Body Coverage
This is the external composition of the body with various types of textures, colors and patterns that have the potential to give visual rhythm to the physical characteristics of the animal. The distribution of fat influences its final shape, and adjusts itself over muscles and bones and adapts to the environment where the organism lives. It can come into physical contact through touch.
Vertebrates
Vertebrates have a skin-based covering, which can be highly specialized for coexistence in their habitats and uses. It can function as thermal insulation, camouflage, sexual attraction, defense or visual communication.
Most mammals are covered with hair or spines, such as porcupines and echidnas, or layers of subcutaneous fat, such as whales and dolphins.
Birds are covered with thin, dry skin and feathers, which are essential for flight and thermal insulation.
Reptiles have horny scales that reduce water loss and provide mechanical resistance, and animals such as turtles have bony shells.
Amphibians have thin, moist skin that is permeable to water and used for gas exchange and hydration.
Fish are covered in scales that reduce friction in the water and protect against predators and diseases.
Invertebrates
Invertebrates also have a wide variety of body coverings, which perform essential functions such as protection, defense, support, gas exchange and prevention of dehydration and influence the interaction of organisms with the environment.
Arthropods have an exoskeleton of chitin or calcium carbonate that protects against predators and dehydration and provides support for the internal muscles.
In mollusks, the presence of a glandular epidermis that secretes the calcareous shell for protection is common, less so in octopuses, which require more mobility for their soft and flexible structures.
Echinoderms have a calcareous endoskeleton covered by a thin epidermis that protects against predators and helps with locomotion in the case of sea urchins.
In annelids, the body is covered by a thin, flexible cuticle that is permeable to water and gases, allowing cutaneous respiration and facilitating movement.
Nemathelminthes have a resistant cuticle composed of collagen, which protects against the hostile environment and maintains the structure of their elongated, cylindrical body.
Platyhelminthes have an elongated structure and a thin, moist integument that allows gas exchange by diffusion, which allows cutaneous respiration.
Cnidarians have a gelatinous body, an epidermis rich in specialized cells that contain toxins for defense and capture of prey by means of cnidocytes.
Poriferans have a porous body that lacks organized tissues; instead, it is covered by an outer layer of cells called pinacocytes, providing structure and protection to the body.
Use of Limbs
The choice between bipedal or quadrupedal walking refers to the way animals move based on the number of limbs they use to walk and influences the bone and muscle structure, balance and even the speed of movement.
Bipeds
These are animals that walk on two limbs in an upright position. The lower limbs are raised and adapted for support and balance, while the upper limbs are free for manipulating objects or flying. Kangaroos and birds are examples of bipeds, in addition to some extinct dinosaurs such as Tyrannosaurus rex and Velociraptor that walked in this position. Although they have more legs, praying mantises are also bipeds.
Quadrupeds
These are animals that move in a horizontal position on four or more limbs, providing greater stability, speed and flexibility, and limiting the use of legs for functions other than locomotion. Most mammals, reptiles and amphibians are quadrupeds, such as Triceratops and Brachiosaurus. Invertebrates, with few exceptions, have this characteristic.
Some quadrupedal animals can occasionally walk and defend themselves as bipeds, such as bears, chimpanzees and meerkats.
Fish do not fit into the bipedal or quadrupedal patterns, as their locomotion occurs through the tail, fins and body movements in the water with the help of muscles. Although most fish swim, certain species have developed terrestrial locomotion skills, such as the mangrove fish uses fins to “walk” on mud underwater. Cetaceans and seals are mammals that have hydrodynamic bodies and modified fins, without articulated limbs for terrestrial locomotion, only crawling when they are out of the water. And groups such as annelids, flatworms, nemathelminthes, cnidarians and poriferans do not have limbs, so they do not fit into bipeds or quadrupeds.
Locomotion Patterns
Refers to the mobility of animals in their environment. The way an animal moves is intrinsically linked to its anatomy and understanding these locomotion patterns is essential to portraying furry characters. Below we have descriptions of different animal movements
Ground
Terrestrial animals present a wide range of forms of locomotion, shaped by gravity and the resistance of the ground. Each of the types of mobility corresponds to the structure of the body and limbs.
•Running
Only the toes of the paws are supported, these are digitigrade animals such as dogs, cats and foxes; and unguligrade animals such as deer, horses and goats, these have the phalanges supported on the ground with hooves around them. They provide fast and prolonged movements.
•Jumping
The hind limbs are larger, more developed and have a Z shape that works like a spring. Rabbits, kangaroos and frogs hop when they move, transmitting momentum, precision and dynamism.
•Gait
Animals that support the entire sole of their paw on the ground are considered plantigrade, having greater stability and strength. Bears, raccoons and badgers, for example, move slowly or march, and are firmer and more robust.
•Reptation
Reptiles such as snakes, lizards and turtles have shorter limbs or no limbs, which result in undulating movements contributing to flexibility and adaptation to uneven and narrow terrain.
•Appendages
This mechanism of locomotion through legs, antennae or fins is quite versatile and ingenious and encompasses several terrestrial and aquatic invertebrate animals, from crabs, lobsters to spiders.
Air
Air locomotion requires a very specialized body structure, since overcoming gravity demands precise work between strength, lightness and aerodynamic control.
•Flight
They use wings to generate lift, allowing agile maneuvers full of energy and lightness. These animals include bats, birds and insects such as canaries, parrots, flies and butterflies.
•Gliding
Some species, such as certain flying reptiles and flying squirrels, extend membranes between their limbs to glide by taking advantage of the air current in the environment, offering them serenity and fluidity in their movements.
Water
In a dense, submerged environment, aquatic animals need to overcome the resistance of the liquid and, at the same time, take advantage of its buoyancy. Their structures often have hydrodynamic shapes.
•Swimming
Fish and dolphins have fins and tails on their backs, and in the case of amphibians, reptiles, birds and semi-aquatic mammals, limbs that function as oars to move through the water and ensure efficiency and resistance in denser environments.
•Contraction
Invertebrate animals such as jellyfish and marine worms swim by contracting their muscles that create wave-like movements and propel their organisms forward smoothly and continuously.
•Propulsion
Nautilus, squid and octopuses capture water in an internal cavity to move quickly, a mechanism that constantly generates sudden, explosive and unpredictable movements.
•Sessile
Not all animals depend on locomotion to survive, as they obtain resources in other ways with the flow of water while fixed to their places, including sponges, corals and anemones, which are mostly aquatic marine animals.
Some species have more than one mode of movement, including bears, ducks, crocodiles, otters and octopuses, and thus their limbs offer more survival mechanisms and reflect the complexity of nature.
By incorporating these nuances into the design of furry characters, it is possible to create figures that not only have a convincing appearance, but that are also characterized by the way they move.
Adapting the Animal Anatomy for Furry Characters
Studying anatomy is the beginning of the emergence of furry characters, which are the main focus of the blog. Here are a series of suggestions for those who want to learn about animal anatomy in a practical way that is adaptable to furries.
Adjustment to the Body and Limbs
The skeleton is the foundation on which the entire base structure is built. To create coherent furry characters, it is essential to understand how it works in the animal based on the previous points analyzed.
•Spine
It should arch in an “S” shape, like the human, which requires redesigning the pelvis and repositioning the center of gravity.
•Pelvis and Hips
It is necessary to redesign the animal’s hips to a wider and more vertical model, giving stability to the bipedal position.
•Forelimbs
They transform into arms. To maintain anatomical coherence, the humerus and radius must align with the scapula adapted for freedom of movement, like in humans.
•Hind Limbs
These function as legs and are used by the characters to stand upright, just like humans. Modify according to the species, its support method and locomotion pattern. If you want to keep digitigrade legs, for example (with a raised heel, like in wolves), it is essential to calculate the new inclination of the femur and tibia to balance the upright body.
Functional Muscles
Focus on the shoulders, chest, hips, thighs, arms for the muscles and observe how they affect the silhouette. In order to avoid making the designs cluttered with unnecessary details, do not copy muscle by muscle. And be careful when suggesting volume, exaggerated muscles can be stylistic, but they should seem useful, do not do them just for aesthetics.
Body Coverage With Direction
Follow the muscle flow when creating textures, this gives more naturalness. The hairs, feathers, scales, skins, shells etc. can follow the natural pattern of the species or be stylized. In specific areas (forelock, tail, mane, sideburns) long, striking coverings help create visual identity.
Where to Look for and How to Apply Anatomy
Use references from real people and animals to understand how to apply tension, contraction and rest to the limbs.
Before drawing the anthropomorphic version, try to imitate them with your own body. If you use photos, mark the points of the structure of the figures you are going to analyze. The more you know the rules of animal anatomy, the freer you will be to transform them with purpose and style.
Remembering Where the Principles for Furry Anatomy Lie
More than a set of skeletons, muscles and coverings that carry evolutionary stories, the physical structure guides movement, intention and function, determining the compositions of the body and how it remains in balance and moves.
Animal anatomy is the essential starting point for bringing to life anthropomorphic characters with personality and visual coherence. The artist needs to know where to preserve the original structure of the represented species and where to adapt elements, understanding the basis for later transformation. A well-constructed furry not only looks like a fusion between human and animal, it moves like one.
Over time it becomes easier to abandon the superficial and delve into creations that have presence, coherence and life. Therefore, mastering animal anatomy is not an end, but a starting point. It is the key that opens doors to infinite possibilities.
