In the wild, predator-prey interactions are central to the evolution and structure of ecological communities, and in this context, cheetahs have evolved the ability to run at high speeds to capture prey. The cheetah is the fastest land mammal in the world. Cheetahs have a top speed of over 110 km/h. 100m sprint in about 6 seconds.
With long legs and a long body, claws that evolved to grab the ground and push them forward, and a long tail for balance, cheetahs are built for speed. But the most important influence on speed is the muscles, more specifically the muscle fibers known as the “fast-twitch” fibers. Fast-twitch fibers contain reserves of energy that can be used to generate brief bursts of power or speed. But it doesn’t take long before they need a break.
Although cheetahs and racing greyhounds are similar in size, cheetahs can reach much higher top speeds. They are the best sprinters in the world and can accelerate at speeds of up to 7.5 m/s and reach speeds of over 28 m/s, which is about twice that of greyhounds, which are considered excellent sprinters.
The cheetah is able to reach a maximum speed of about 29 m/s (1749.40 m/min), compared to the top speed of 17 m/s achieved by racing greyhounds, and runs at speeds, which can exceed 100 km/h. However, most cheetah hunts only involve moderate speeds.
During a sprint, heat production from muscle activity increases by about 60 times the heat production at rest. Most of this heat (70%) is stored, the normal mechanism of evaporative heat loss is not activated during the race. Cheetahs stop running when their rectal body temperature reaches 40.5C. So it seems that their body temperature determines the distance they run, after which they give up the pursuit unsuccessfully after a few hundred meters.
Females are faster than males.
Cheetah have longer forelimbs, in which the radius and humerus are almost identical, and the bones of the lower limbs are proportionally shorter. The extended legs give the cheetah a longer stride. In addition, the bones of the lower legs and feet are thin and light. They have the longest and most flexible spine of any big cat, which helps increase stride length.
When running, the cheetah has all of its feet in the air for more than half of each stride. The cheetah’s claws can only be partially retracted, and its legs lose the fur sheaths found on most other cats. At high speeds, the jaws are always fully extended; Here they act like spikes on a sprinter and improve grip.
The spur is a very important tool in hunting. Cheetahs use it to hook and trip prey in the final moments of the hunt. This makes it the relatively largest spur among the big cats. Also, the footpads are very hard with grooves, this increases traction. The tail is long, muscular, and tubular to provide balance during quick changes of direction while hunting.
Cheetahs have small canines with small roots; This makes room for the enlarged nostrils that allow the cheetah to breathe while suffocating its prey. In addition, they have enlarged lungs, bronchi, an oversized heart, and muscular arteries. A cheetah’s normal respiratory rate ranges from 2,030 breaths per minute, increasing to 150,200 breaths per minute after a high-speed hunt.
It is believed that these high speeds allow cheetahs to pursue slower prey, with failed hunts being attributed to exhaustion and/or overheating. However, their running pattern during a chase reflects a different hunting strategy. The pursuit involves an alternation between frontal and lateral acceleration, the range of which varies depending on the prey species. Therefore, during a chase, they first accelerate to close the distance to their prey before slowing down 5 to 8 seconds after the chase ends so they can turn quickly to accommodate any prey escape tactics that involve sudden changes in the direction and that is difficult to adapt to the increasing speed.
In addition, turning at higher speeds exerts a greater force on animals’ limbs and muscles, especially at acute turning angles, and increases the risk of injury. As a result, although the ability to hunt at high speeds can allow cheetahs to evade prey, they may not always choose to run at top speeds, particularly when pursuing prey species that attempt to evade them by making sudden changes in direction.
These hunting strategies require specific anatomical configurations that allow them to generate speed and deal with the torsional forces caused by high speed and sudden changes in direction caused by their prey’s typical evasive movements.
Cheetahs have unusually long strides that contribute significantly to the speeds they achieve when walking run fast. The configuration of their skeletal and muscular structures amplifies the large angular movements of the limb joints, which lengthen the stride length as the spine flexes and extends. The muscles of the back, due to their inherent composition of muscle fibers, have the ability to produce a strong and rapid extension of the spine. spine and increase its stiffness during locomotion, which increases the power of forwarding propulsion when running.
Increasing stride frequency by rapidly swinging the limb and thereby decreasing swing time also allows quadruped sprinters to achieve higher speeds. Cheetahs, however, generally use a lower stride rate than greyhounds at any speed and stride frequency does not appear to contribute substantially to the high speeds achieved by cheetahs.
The transverse gallop is characteristically that of the horse, while cheetahs use the rotary gallop.The fundamental difference between these gaits is determined by which set of limbs, front or back, initiates the center of gravity transition, from a downward–forward to upward–forward trajectory that occurs between the main portions of the stride when the animal makes contact with the ground. During a stride, when their feet are in contact with the ground, animals support their body weight by resisting the joint torques caused by the impact.
At high speed, however, such as in cheetahs running at speed, the hind limbs support the majority of an animal’s body weight, and within this context, cheetahs support 70% of their body weight on their hind limbs at speeds of 18 m/s. The hindquarters thus generate most of the muscular activity required for propulsion. It is assumed that supporting a greater proportion of body weight on a particular limb is also likely to reduce the risk of slipping during propulsive efforts. When traveling at top speed the cheetah’s forelimbs also experience very high peak forces, and they too must be able to cope with large joint torques but they do not contribute substantially to generating the superior speed of cheetahs.
Muscle structure and conformation
The distribution of skeletal muscle along the legs plays a role in animals that have the ability to reach high speeds and have to accommodate high impact pressures during a chase. In cheetahs, the proximal limbs contain many, large, PCSA (physiological cross-sectional area) muscles. This configuration provides the limbs with the ability to resist and absorb large impacts. The legs, because of these muscle masses that can absorb some of the impacts, do not merely function as simple struts and, because of the muscle distribution, they can absorb much of the force of impact while running. This conformation also provides cheetahs with the ability to control and stabilize their legs during high-speed maneuvering such as is needed during a chase. The large digital flexors and extensor muscles characteristic of the cheetah’s forelimb, allow it to dig its digits into the ground, providing the required traction when galloping and maneuvering at speed.
Muscle fibre composition and characteristics
Muscle consists of muscle fibres (Type I and Type II fibres) that have different functional and metabolic characteristics. The characteristic species-specific variations in fibre composition reflect the physiological needs of individual animal species, and in felids generally, the fibre type composition of hind limb muscles matches their daily activity patterns.
Roaming tigers, for instance, walk long distances, while cheetahs have requirements for speed and power over short distances. There is a relationship between the amount and type of activity, and the myosin heavy chain (MHC) isoform composition of a muscle in that tigers have a high combined percentage of the characteristically slower-twitch fibre isoforms required for sustained activity (MHCs I and IIa).
Cheetah locomotory muscles contain a high proportion of fast-twitch fibres, needed for rapidly swinging their limbs and reducing limb swing-times required for running at speed over short distances. In their hind limb muscles, there is a higher percentage of Type II (Type IIa + IIx) fibres than in the forelimb muscles further confirming that the propulsive role of the hind limb is greater than the forelimb.
Enzyme activity in cheetah muscle reflects a high capacity for glycolysis in anaerobically based exercise required for sprinting during high-speed chases for hunting purposes. The fibre type composition, mitochondrial content, and glycolytic enzyme capacities in the locomotory muscles of cheetahs operate at the extreme range of values for other sprinters bred or trained for this activity including greyhounds, thoroughbred horses and human athletes
Fast-twitch fibres run mainly on an energy system that doesn’t need oxygen. This is called anaerobic energy.
Slow-twitch muscle fibres, on the other hand, are less energetic but can be used for a lot longer before they get tired. They use an aerobic energy system,
and require oxygen. Cheetahs and other fast animals have loads of fast-twitch fibres in their muscles. Rather than using oxygen, slow-twitch fibres quickly burn through the body’s supply of a fuel called adenosine triphosphate or ATP. Found in all lifeforms, ATP is the molecule that stores the energy we need to do just about everything we do and is present in every cell of the body.