Having trained many years in martial arts, I am very familiar with what kicking means in the context of fighting and combat. It is a sudden, rapid motion of the legs intended to strike a target. As we know, the legs are stronger limbs compared with the upper limbs. They are normally used for locomotion, for human beings, it means walking and running. Therefore, they have to be naturally stronger in order to carry weights. The impact generated from such a rapid motion of the legs can not only cause damage when striking a target, but can also be used to propel oneself towards the opposite direction, therefore, the techniques are used by many creatures when in the water or on the sky.
Kicking, as a human weapon, although consist of many varieties, the essential is the same. That is to strike an object from different angles without compromising the attacker's balance. Despite many different types of kicking techniques, they are either forward thrusting kicks or looping kicks. Both are the natural instinct of all human being. Martial artists simply refine the motions and make them more effective and unpredictable.
A round house kick looks like this with an object as a soccer ball, it travels in a looping path.
A straight kick is like the below with a straight forwarding motion:
For human beings, this is how we kick in accordance with our natural physiques. In any physical conflicts, kicking (if used at all) won't be any different from these 2 types as long as the parties are still in their natural stances.
Mammals on the other hand, kick differently. Since they have to use all 4 limbs in their natural stances, their kicking are more limited. Only the creatures with legs at certain length are capable of kicking. Horses, zebras, deer, giraffes are most commonly observed using kicking to defend themselves. Because they are naturally good runners that need to protect themselves from threats from the back, their kicking is exclusively backwards with the front limbs supporting the body.
Creatures like elegant can't kick simply because they are too heavy. Others such as ox, Rhinos, Hippos, pigs, rats can't neither because their legs are too short.
Kangaroo is a very interesting creature. Their legs have comparable strength with horses, but because they naturally stand upright, so they kick forwards, complete opposite of horse kicking and more similar to human. Since they never had natural predators in Australia, they never had to develop the ability to kick backwards while being chased. Therefore, most of the time they use kicks to fight other kangaroos. They will use their tails as support so they can lift both legs to kick forward.
Now when it comes to creatures of wings, legs almost become their exclusive weapons when it comes to killing preys or fighting since wings are so important to their survivals that they can not afford to break them. These creatures have evolved to be able to kill or fight using lethal talons as claws from their legs. Wings allow birds of preys to elevate to any heights, therefore, the attack can come from all directions, specially in the air combat. However, their kicking motion is only limited to forward (and downward) path. When the motion becomes rapid (meaning a kick), their talon can be used to slash the flesh of their rivals. Or they can use it as claws to grab onto their preys.
Aerial combat between two birds of preys
Great eagle has always been an inspiration to humans:
These are the most commonly observed kicking behavior of the natural world when it comes to combats. There are other types of kicking such as one is completely on the ground facing up and kicking with both legs to fend off the attack from above. However, these are more passive defending rather than active attacking techniques.
When it comes to kicking, although only some creatures would actively use it in combat, more creatures use them for locomotion. Most of the aquatic vertebrates use kicking motion to propel themselves forward. The most trivial example would be frogs. The more powerful the kick, the faster it propels forward
Enough of kicking. Isn't it fascinating?
Thank you
