Which Mammals Can Fly?

Many people think that there are no mammals can fly, but this is not correct. However, while some species can glide between trees, only one family of mammals can truly fly

Bats are the only mammals that have wings and achieve true flight. There are over 1,100 species of bats worldwide, and they have all adapted to fly. Other mammals such as flying squirrels, gliders, and colugos are not capable of flight but glide from tree to tree.

If you have ever wanted to know more about how bats fly, and what makes them different from other mammals, there is some great information here.

Bats Are The Only Mammals That Fly 

Over time, many animals have evolved to include aerial locomotion. Some of them have achieved this by either flying or gliding. While others glide from tree to tree, bats are the only mammals capable of powered flight and achieve true flight.

How Did Bats Get Their Name?

Bats belong to the order Chiroptera. Chiroptera comes from Greek words meaning hand and wing. The hand in Greek is “cheir,” and the wing is “pteron.” The name reflects the unique anatomical feature of bats, which have wings formed from elongated fingers covered by a thin membrane of skin, giving them the ability to fly.

Two Types Of Flight

There are two types of flight and both have major differences. The two types are powered flight, also known as true flight and gliding. 

Powered (True) Flight

Powered flight is also known as true flight. Most birds, insects, and bats are capable of powered flight. The flapping of their wings completes powered flight to keep them aloft.

Powered flight in animals refers to the ability of certain species to generate and control the lift necessary to stay airborne using their own muscular energy.

Powered flight requires the coordinated movement of wings or other specialized structures to generate the necessary aerodynamic forces that counteract gravity and allow the animal to remain aloft.

Bats are the only mammals capable of sustained powered flight. Their wings are formed by a membrane of skin stretched between elongated fingers and their hind limbs. Bats flap their wings similarly to birds, using the motion to generate lift and thrust. Bats are highly maneuverable and can perform intricate aerial acrobatics, making them well-suited for navigating through complex environments.

Evolution has adapted bats by modifying their front limbs into wings, shortening their torso, enlarging their heart and thorax, improving their vision, and lightening their bones.

Animals that fly include:

1. Bats: Bats are the only mammals capable of sustained powered flight. Their wings are formed by a membrane of skin stretched between elongated fingers and their hind limbs. Bats flap their wings similarly to birds, using the motion to generate lift and thrust. Bats are highly maneuverable and can perform intricate aerial acrobatics, making them well-suited for navigating through complex environments.
2. Birds: Birds are well-known for their ability to achieve powered flight. Their wings are modified forelimbs covered with feathers. By flapping their wings in a specific motion, birds generate lift and thrust, allowing them to control their direction and altitude in the air. Different bird species have adapted their wing shapes, sizes, and wing-beat patterns to suit their specific ecological niches and flying styles.
3. Insects: The ability of insects to maneuver through the air is impressive. They can hover, glide, and perform intricate aerial movements, which are crucial for tasks such as capturing prey, escaping predators, and finding suitable habitats. Insects have evolved a wide array of sensory structures, such as compound eyes and antennae, that help them navigate and interact with their environment effectively.

Gliding

Gliding in animals refers to the ability of certain species to move through the air using their bodies to catch air currents and achieve controlled movement without the need for active flapping like in powered flight. Gliding allows these animals to travel between locations or search for food by utilizing the aerodynamic properties of their bodies and environmental factors such as wind and gravity.

Many people think that flying possums and flying squirrels can fly. This is often confusing because these animals have names that suggest they can. They do not fly but glide for short, limited distances.  

Animals that glide include:

1. Flying Squirrels: Flying squirrels are small rodents with a flap of skin called the patagium that extends between their forelimbs and hindlimbs. By spreading their limbs and stretching the patagium, flying squirrels can glide from tree to tree. They control their direction and speed by adjusting their body position and the tension of the patagium.
2. Sugar Gliders: Similar to flying squirrels, sugar gliders are small marsupials equipped with a patagium that extends between their wrists and ankles. They are native to Australia and nearby islands and use gliding as a means of moving through the forest canopy in search of food and shelter.
3. Colugos: Colugos, also known as flying lemurs, are arboreal mammals found in Southeast Asia. Despite their name, they are not true lemurs and cannot fly. Instead, they have a large patagium that stretches from their neck to the tips of their fingers and toes. Colugos can glide impressive distances, often exceeding 150 feet (45 meters).

There are two types of gliding. These are soaring and gravitational gliding.

Soaring

Soaring in animals refers to the ability of certain species to maintain extended periods of flight with minimal active flapping by utilizing natural air currents and updrafts. Soaring allows these animals to cover long distances while conserving energy. Instead of relying on continuous wing flapping, they take advantage of rising air masses, such as thermals, ridge lift, and wind currents, to stay aloft.

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Gravitational Gliding

If an animal uses gravitational gliding, it can direct where they want to go. Mammals such as flying squirrels and colugos will jump in the direction they want to glide, although they can also use the membrane between the front and back limbs to act as a parachute.   

Gravitational gliding in animals refers to the ability of certain species to achieve gliding flight by taking advantage of the force of gravity. Instead of actively flapping their wings or using external sources of lift like air currents, these animals use their bodies and specialized adaptations to control their descent and move through the air in a controlled manner.

Here are a few examples of animals that use gravitational gliding:

1. Flying Squirrels: Flying squirrels have a flap of skin called the patagium that stretches between their forelimbs and hindlimbs. By spreading their limbs and extending the patagium, flying squirrels create a larger surface area to catch air and generate lift. They then use their body positioning and tail movements to control their glide path.
2. Sugar Gliders: Similar to flying squirrels, sugar gliders are marsupials with a patagium that extends between their wrists and ankles. They use the patagium to glide between trees in search of food and shelter. Sugar gliders can control their glide by adjusting their body posture and the tension of their patagium.
3. Colugos (Flying Lemurs): Colugos have a large patagium that stretches from their neck to the tips of their fingers and toes. They are skilled gravitational gliders and can cover significant distances using their specialized membrane. Colugos use their patagium to control their gliding direction and speed.

Adaptations To Flight

Bats have evolved a variety of adaptations that allow them to achieve powered flight, making them unique among mammals. These adaptations encompass their anatomical, physiological, and behavioral traits, all of which contribute to their remarkable flying abilities. Here are some key adaptations that bats have developed to excel in flight:

1. Wings and Flight Skeleton: Bats have a wing structure formed by elongated fingers and a thin membrane of skin, called the patagium, that stretches between the fingers and the body. The fingers and bones in the wing are highly specialized to support the wing’s shape and movement during flight. The bones are lightweight but strong, and the joints allow for flexibility and precise control of wing shape.
2. Pectoral Muscles: Bats have strong pectoral muscles, which are responsible for powering the flapping motion of their wings. These muscles are adapted for rapid contractions and sustained effort, enabling bats to generate the necessary lift and thrust for flight.
3. Metabolism and Energy Efficiency: Bats have a high metabolic rate relative to other mammals, which is necessary for the energy demands of flight. They can consume large amounts of food in relation to their body size to support their energy needs. Bats are also highly efficient in converting food into energy, allowing them to sustain flight for extended periods.
4. Heart and Circulatory System: Bats have a heart and circulatory system adapted to support the demands of flight. Their hearts beat rapidly during flight to deliver oxygen-rich blood to their muscles and other tissues. This increased circulation helps meet the oxygen needs of their highly active muscles.
5. Respiratory System: Bats have efficient respiratory systems that enable them to exchange gases effectively during flight. They have large lung capacity and can rapidly exchange oxygen and carbon dioxide, supporting their high metabolic rate and oxygen demands.
6. Sensory Adaptations: Bats have well-developed senses that aid in flight. Their sense of hearing is particularly important for echolocation, a unique adaptation where bats emit high-frequency sound waves and listen to the echoes to navigate and locate prey in the dark.
7. Adaptations for Maneuverability: Bats possess excellent maneuverability in flight. They can change the shape of their wings, adjust the angles of their wing surfaces, and alter the frequency and amplitude of wing beats to control their movements with precision. This allows them to navigate through complex environments and capture agile prey.
8. Thermoregulation: Bats have adaptations for regulating their body temperature during flight. Flying generates heat, so bats have mechanisms to dissipate excess heat, such as increasing blood flow to their wing membranes and exposing their wings to the air.

How Do Bats Fly? 

Bats fly using a combination of specialized anatomical features, muscular strength, and coordinated wing movements. Their flying technique is distinct from that of birds or insects and involves several key steps:

1. Wing Structure: Bats’ wings are formed from elongated fingers (metacarpals) and a thin membrane of skin, called the patagium, that stretches between the fingers and the body. This wing structure allows for flexibility and manipulation of wing shape during flight.
2. Flapping Motion: Bats achieve flight through a rhythmic flapping motion of their wings. The flapping motion is powered by strong pectoral muscles in the chest and shoulders. These muscles contract rapidly to move the wings up and down.
3. Lift and Thrust: During the upward wing stroke, the bat generates lift by pushing against the air. This upward movement creates an area of lower pressure above the wing, causing the bat to rise. During the downward wing stroke, the wings provide thrust as they push against the air to move the bat forward.
4. Maneuverability: Bats are incredibly agile fliers, capable of rapid and precise movements. They adjust the angles of their wing surfaces and the shape of their wings to control direction, speed, and altitude. This flexibility allows them to navigate complex environments and capture agile prey.
5. Echolocation: Many bat species use echolocation, a biological sonar system, to navigate and locate prey in the dark. Bats emit high-frequency sound waves, and when these waves hit objects or surfaces, they bounce back as echoes. Bats can interpret these echoes to create a mental map of their surroundings.
6. Wing Adjustments: Bats can vary the frequency and amplitude of wing beats based on their flight goals. For instance, hovering bats beat their wings more rapidly and create strong lift, while bats in pursuit of prey might perform faster wing beats to chase their target.
7. Gliding and Soaring: Some bats are capable of gliding or soaring by using updrafts and air currents. They can stretch their wings and patagium to create a larger surface area, allowing them to glide for longer distances without active flapping.
8. Energy Efficiency: Bats have adaptations for energy-efficient flight. Their lightweight bones and efficient respiratory systems support their high metabolic rates during flight. They are also capable of entering periods of torpor (reduced metabolic activity) to conserve energy when not actively flying.

Overall, bats’ ability to fly is a result of their unique wing structure, powerful muscles, efficient metabolic systems, and exceptional coordination of movement. These adaptations have allowed them to evolve as highly successful and diverse flying mammals.

Why are bats mammals?  Find out here

Can Bats Take Off From the Ground?

Some species of bats can take off from the ground. However, those with longer, narrower wings are unable to take off from the ground.  

A large majority of bat species cannot take off from ground level. These species of bats will hang on a cliff or a tree in order to take off. When a bat is launching itself, it will drop from the hanging position before flying.  

Some bat species, such as horseshoe bats and vampire bats can take off from the ground. These species descend to the ground to search for food.

These bats land by decelerating their speed until they stall. They will then hold onto a branch or other suitable surface before dropping lower.

Vampire bats usually feed on the blood of mammals, usually large sleeping animals. They use their razor-sharp teeth to cut into the flesh and suck out the blood. Vampire bats have to land close to ground level to feed on their prey.

Vampire bats and other bat species that prey on terrestrial mammals or feed on flowers can also hover. 

Can Bats Walk On The Ground?

Several species of bats can move around while on the ground. The first digit on the wing of the bat is small in size but has a claw, similar to the human thumb.

These species use the first digit when climbing or walking on the ground. They also have stronger forelimbs and weak hind legs, which allow them to crawl on the floor. 

Most species of bats that are insectivores have this adaptation. These species usually feed on ground and flying insects.

Bat Sizes And Population

Among all the species, the smallest bats are Kitti’s long-nosed varieties with wings up to 5.91 inches. The largest bat is the giant golden-crowned flying fox that usually grows to about 1.6 kg with wings as long as 1.7 meters. 

According to statistics, there are 1,100 species of bats globally, and of these, 40 species live in the U.S. Bats, insects, and birds make up a large number of species and individuals. Flying animals are some of the most successful of all creatures.

Bats evolved a long time ago. For more information on how and when they evolved, I have written this article.

Why do Bats Fly Low?

Bats often fly at low altitudes for several reasons that are related to their feeding and navigation strategies, as well as their energy efficiency and safety. Here are some common reasons why bats fly low:

1. Hunting for Prey: Many bat species are insectivores, and they primarily hunt flying insects as their main food source. Flying insects, such as moths, mosquitoes, and beetles, are abundant in the lower levels of the atmosphere, closer to the ground. By flying low, bats can more effectively detect and capture their prey.
2. Echolocation: Bats use echolocation to navigate and locate prey in the dark. Echolocation involves emitting high-frequency sound waves and listening to the echoes that bounce back from objects and obstacles. Flying at lower altitudes allows bats to receive clearer and more accurate echolocation signals, helping them avoid collisions and locate prey more precisely.
3. Visual Navigation: While echolocation is crucial, some bat species also rely on their vision to navigate. Flying closer to the ground provides visual cues that help them orient themselves and navigate through their environment, especially in dim light.
4. Reduced Wind Interference: Flying close to the ground can reduce the effects of strong winds and turbulent air currents that are often more pronounced at higher altitudes. This allows bats to maintain better control over their flight and maneuver more easily.
5. Thermoregulation: Bats are ectothermic animals, meaning their body temperature is influenced by external conditions. By flying closer to the ground, they can benefit from the slightly warmer air near the Earth’s surface, especially during cooler evenings and nights.
6. Escape from Predators: Flying at low altitudes provides bats with more opportunities to take cover in vegetation or other structures, making it easier for them to evade predators. Bats can quickly dart into hiding places or change direction to escape threats.
7. Feeding Strategy: Some bats have specific feeding strategies that require them to fly close to the ground. For example, certain bat species specialize in gleaning insects from surfaces, such as leaves or water surfaces. Flying low allows them to access their preferred feeding locations.

How Do Bats Navigate When Flying?

When flying at night, bats use echolocation to notice barriers, predators, and prey. Bats use echolocation due to their speed and maneuverability while flying.     

Because bats use echolocation, many people think they bats are blind, but this is not true. Bats can see almost as well as humans.

Echolocation is a mechanism where bats emit ultrasonic sounds, which moments later send echoes back. When the echo returns to the bat, they can easily detect and locate an obstacle or predator.

Are Bats Becoming Extinct? 

Bat populations are drastically declining because of several factors.

Although they are considered signs of good fortune in many societies globally, there are many misconceptions about bats. Some cultures claim that they bring bad omens and diseases. Therefore, they are not protected in many areas. 

Bat populations are highly threatened by habitat loss, climate change, and attacks from predators. They are also affected by a fungus called white-nose syndrome which is deadly and causes huge numbers to die.

Bats are very beneficial and influential in controlling the ecosystem. Bats are excellent pollinators concerning seed dispersion, fruit dispersion, and managing and eliminating crop-destroying insects.

Do bats live in the cold conditions of Alaska? Find out in this article I have written here.

References And Further Reading

Bat Evolution, Ecology, and Conservation by Rick A. Adams and Scott C. Pedersen

This book covers various aspects of bat biology, including their evolution, ecology, and flight adaptations. It provides insights into the unique features that allow bats to fly.

Bats: A World of Science and Mystery by M. Brock Fenton and Nancy B. Simmons

While this book explores all aspects of bat biology, it dedicates a significant portion to bat flight. It discusses the mechanics and aerodynamics of bat flight in an accessible way.

The Bat: Wings in the Night Sky by John F. Waters and Joseph R. Tomelleri

This book focuses on the natural history of bats, including their flight abilities. It’s beautifully illustrated and provides an in-depth look at the lives of bats.

Bat Flight: A Comparative Study by John W. Hermanson and Sharon A. Hermanson

This book takes a comparative approach to studying bat flight. It explores the flight mechanics of various bat species and highlights the diversity of flight adaptations among them.

Bats: From Evolution to Conservation by Teeling, E. C. (Editor)

While this book covers a wide range of bat-related topics, it includes chapters on bat flight and echolocation, offering valuable insights into the mechanics of bat flight.