Dec 17

December 17th is the official anniversary of the first human flight in a powered, heavier-than-air plane, so to mark this historic event we have taken a look at how flight has been mastered by both animals and humans.

The Wright Flight

Little did the Wright Brothers know that when they boarded their muslin-covered, wooden plane on that December morning that they would be paving the way for aviation as we now know it. It is astounding to think how far air travel has come in the last 108 years. We now have planes that can carry over 500 passengers to the other side of the world, in extraordinary comfort in less than 24 hours, the prospect of which back in 1903 would have sounded like something fresh from the pages of a science-fiction novel!

Photo of the first successful flight of the Wright Flyer, by the Wright brothers.

First successful flight of the Wright Flyer, by the Wright brothers.

 

Animal Inspiration?

Animals conquered flight long before 1903, admittedly in a slightly different fashion. It has proved such a successful strategy that it has evolved independently four times in birds, bats, insects (and pterosaurs), and each of the extant groups is still going strong.

Photo of a Mauritian flying fox in flight

Bats are the only group of mammals to have evolved the ability to fly.

Bats are the second most diverse group of mammals and the only mammal to have developed true powered flight. Birds have the most species of any class of terrestrial vertebrates, and there are more species of insect than all other animals added together, so they must be doing something right!

Photo of a Harlequin ladybird in flight

Insects are the only class of invertebrate that can fly.

 

Glorious Gliders

The Wright Brothers started out building gliders before honing their designs and moving onto powered flight. Gliding is also a popular strategy in the natural world and can be seen in mammals including the northern flying squirrel. This nocturnal mammal glides between trees using a fold of skin that stretches between its wrists and ankles. This parachute effect allows it to travel up to 45 metres in a single glide, using its tail as a rudder.

Photos of the northern flying squirrel

The northern flying squirrel can glide as far as 45 metres.

 

Recipe For Success

So why was it that the Wright Brothers succeeded when so many others had tried and failed? The answer is quite simple; they had achieved both power and control, using a specially designed lightweight engine and controls that allowed the pilot to steer effectively. One of the best examples of powerful, controlled flight in birds has to be the kestrel. Kestrels hunt by sight and are able to hover perfectly still in mid air, even in heavy winds. Once they have locked their sights onto their prey they are able to dive to capture it with incredible accuracy.

Photo of a kestrel in flight

Kestrels exhibit both power and control in flight.

 

Did you know?

  • The wandering albatross has the largest wingspan of any bird, measured at over 3.5 metres, and spends the majority of its life in flight.
  • The bee hummingbird is the smallest bird in the world and has the smallest wingspan of any bird. It is capable of beating its tiny wings up to 80 times a second.
  • One of the heaviest flying birds is the kori bustard which can weigh as much as 20 kilograms.
  • The longest invertebrate annual migration is carried out by the monarch butterfly across North America.
  • The longest bird migration is undertaken by the Arctic tern which traverses the globe on its annual pole to pole journey, meaning it sees more sunlight each year than any other animal.

 

Photo of an Arctic tern adult feeding young

Arctic terns undertake the longest bird migration

Photo of a wandering albatross in flight against stormy sky with pair displaying in backgroud

The wandering albratross has a huge wingspan!

 

 

 

 

 

 

 

 

 

Brilliant Biomimicry

The natural world has long been used as inspiration for technological advances, particularly with when it comes to flight. Leonardo da Vinci was a keen observer of the anatomy and flight of birds and even the Wright Brothers were thought to have studied pigeon flight. As our understanding of biomechanics and animal movement advances it will be exciting to see what’s next for biologically inspired engineering – here’s to seeing what the next 108 years bring!

Laura Sutherland, ARKive Education Officer

Aug 4

Vampire bats use infrared sensors to detect veins on their warm-blooded prey, according to new research.

Photo of common vampire bat's open mouth, showing teeth

Common vampire bat showing teeth.

In a study published in the journal Nature, the researchers found that vampire bats have evolved specialised heat-sensitive nerve channels around the nose. These allow the bats to home in on “hot spots” on their prey, where veins run close to the surface of the skin.

In other animals, including humans, these nerve channels are used to detect heat that would be damaging to the body, triggering a painful, burning sensation at temperatures above 43ºC. However, in the vampire bat the channels around the nose have evolved to activate at a much cooler 30ºC, allowing the bat to detect the body heat of its prey.

Blood-sucking bats

Found in Central and South America, the vampire bat is a widely feared species that has been commonly misportrayed as a creepy, blood-sucking killer. However, this small mammal rarely kills its prey and displays many fascinating adaptations to its lifestyle.

Photo of common vampire bat on ground

Common vampire bat on ground.

Its teeth are razor sharp, meaning its victim rarely notices being bitten, and it releases chemicals into the wound which keep the blood flowing, allowing the bat to lap it up with the help of grooves on its tongue.

The vampire bat also has strong limbs and an elongated thumb to help it climb around on its prey and take off after feeding. It rarely bites humans, usually preferring to feed on the blood of birds and other mammals, particularly livestock. Vampire bats also show a rare form of ‘reciprocal altruism’, in which well-fed individuals regurgitate food to hungry companions, even if they are not related.

Photo of common vampire bat feeding on cow

Common vampire bat feeding on cow.

Rare heat-sensing ability

Only three other vertebrate groups are known to have a heat-detecting ‘sixth sense’ – the distantly related pitvipers, pythons and boas. These three snake lineages use specialised structures on the face, known as ‘pit organs’, to detect warm-blooded prey. However, they use a different mechanism to the vampire bat.

Photo of yellow-blotched palm-pitviper, head detail

Yellow-blotched palm-pitviper. Three groups of snakes, including pitvipers, detect heat using specialised ‘pit organs’ on the snout.

The ability to find its next meal is especially important to the vampire bat as it must have a blood meal at least once every few days to survive.

In addition to revealing more about the bat’s intriguing adaptations, the researchers hope that this study will help shed more light on how heat sensors work in humans. It may even help scientists to design drugs to suppress the activity of related nerve channels, such as those involved in inflammatory pain.

Read more about the study at Nature News – Vampire bats turn down the heat sensors to hunt.

View photos and videos of bats on ARKive.

Liz Shaw, ARKive Species Text Author

Jul 26

Cold, wet, dark… but lifeless? Certainly not! Caves are home to many weird and wonderful lifeforms with special adaptations that make living in this inhospitable environment possible. Here are our top ten troglobiotic species!

Winter wren

Winter wren photo

Strangely our first selection doesn’t live in caves at all. The scientific name of the winter wren Troglodytes troglodytes means cave dweller but this name actually comes from the way it hunts insect prey by nipping in and out of cracks and crevices.

No-eyed big-eyed wolf spider

No-eyed big-eyed wolf spider photo

When you spend all your time in the dark eyes become an unnecessary but expensive organ to maintain. Many cave species have lost their eyes altogether resulting in an identity crisis for the no-eyed big-eyed wolf spider.

Alabama cave crayfish

Alabama cave crayfish photo

A life without sunshine makes protective pigmentation unnecessary. For the Alabama cave crayfish this adaptation has made its shell translucent so it’s possible to have a peek at its insides.

Fungus gnat

Fungus gnat photo

Colonies of fungus gnat larvae hang silk threads covered in sticky beads of slime from cave roofs to catch their prey. These gruesome youngsters use bioluminescence to lure flying insects into their dangling traps.

Velvet worm

Velvet worm photo

Another pigment free cave dweller is this species of velvet worm, it is one of only two troglobiotic velvet worms to have ever been discovered.

Madagascan rousette

Madagascan rousette photo

When asked to think of animals that live in caves bats are likely to spring to mind, but many bats don’t roost in caves at all, preferring a nice snug hollow in a tree. The Madagascan rousette is one species of bat that will roost in caves.

Cave salamander

Cave salamander photo

This cave salamander is also known as the human fish. Apparently its fleshy skin makes it resemble a small person. Subterranean darkness must be the only place that this beast could be mistaken for a human!

Iran cave barb

Iran cave barb photo

Like most cave species the range of the Iran cave barb is highly restricted. This fish has only been found in one subterranean river system in south-west Iran.

Nelson cave spider

Nelson cave spider photo

The Nelson cave spider is an ambush predator that hunts in the complete darkness of its limestone cave habitat. It is New Zealand’s only protected spider and also its largest.

Cave catfish

Cave catfish photo

The cave catfish is found in the Aigamas Cave in Namibia. An opportunistic feeder it’s only apparent food source is the particles that fall into the lake from the cave above including bat droppings and animal carcasses.

Have you found an interesting cave species on ARKive that doesn’t feature in our top ten? If so, tell us about it!

Eleanor Sans, ARKive Media Researcher

May 27

So, what is the first thing that springs to mind when you think of bats? Ugly? Scary? Spread diseases? Get tangled in your hair? Think again!            

The world’s 1100 bat species are some of our most misunderstood species, surrounded by myths and superstitions. Contrary to their rough reputation, bats help maintain and enhance biodiversity and their economic value to the agricultural industry is worth billions each year.           

The Year of the Bat 2011-2012 is a two-year campaign, launched by The UNEP Convention on Migratory Species (CMS) and The Agreement on the Conservation of Populations of European Bats (EUROBATS), to celebrate the importance of bats in healthy ecosystems and human economies, and promote a greater awareness of bat conservation.      

As the spotlight shines on the masters of the night, ARKive has teamed up with Planet Science and the Year of the Bat team to make our very own quiz! Check out why ARKive thinks bats are simply brilliant and then head to the “Big Bat Quiz” on the Planet Science website.     

Wing-tastic

Our only true flying mammals, bats have membranous wings, each supported by an arm and four elongated fingers. The large flying fox (Pteropus vampyrus) fruit bat has the largest wingspan measuring a whopping 1.8 metres. Some bats, such as Daubenton’s bat (Myotis daubentonii), have been observed using their wings or tail membrane ‘scoop up’ prey.             

Male large flying fox photo

Male large flying fox with wings outstretched

 
Most bats are small enough to fit in the palm of your hand. The smallest is Kitti’s hog-nosed bat (Craseonycteris thonglongyai), also known as the bumblebee bat, weighing less than 2 grams.           

Kitti's hog-nosed bat photo

Kitti's hog-nosed bat

Echo. . . echo. . . echo   

Many nocturnal microbats use echolocation. They emit high frequency outbursts and interpret the echoes, building an accurate ‘visual map’ to locate prey. Bat calls range in frequency from 14,000 to well over 100,000 Hz and some bats can use habitat-specific calls. The large-eared horseshoe bat (Rhinolophus philippinensis) hunts moths and other insects and has a nose-leaf and large ears which help with echolocation.           

Large-eared horseshoe bat photo

Large-eared horseshoe bat

Bug buster  

The little brown myotis (Myotis lucifugus) can consume 600-1000 insects in a single hour! Microbats are the major predators of night-flying insects, many of which are agricultural pests. As bat numbers decline, pests increase and more pesticides are used, increasing the cost of crop production.          

Little brown myotis photo

Little brown myotis in flight

Passionate about plants  

Fruit bats have excellent eyesight and a keen sense of smell to locate over-ripe fruits like mangoes, figs and guavas. More than 300 tropical plant species depend upon bats for either seed dispersal or pollination and many of these are economically important to humans for products including timber, fruits and spices.        

Nectarivorous bats are well adapted to feed on nectar as they have a long snout and tongue. The Mexican long-tongued bat (Choeronycteris Mexicana) is the main pollinator of several agave species.            

Mexican long-tongued bat feeding photo

Mexican long-tongued bat feeding at night on Agave blossom nectar

A socialite with family values  

Some bats like the hoary bat (Lasiurus cinereus) live a solitary life, but others such as the Brazilian free-tailed bat (Tadarida brasiliensis) live in colonies. Brazilian free-tailed bats form the largest warm-blooded colony in the world; one cave in Texas contains 20 – 40 million individuals! Pups are placed in maternity colonies from which a mother is able to pick out her young.      

Brazilian free-tailed bats photo

Brazilian free-tailed bats emerging at sunset

Sadly an estimated 25% of all bat species are threatened with extinction, mainly due to habitat loss and degradation.          

You can help bats by spreading the word about the Year of the Bat campaign. Why not join your local bat conservation group or build a bat house for your garden?     

Remember to have a go at the “Big Bat Quiz” to find out if  you are a bat boffin or a dingbat. Let us know your score!             

Planet Science logo Year of the Bat logo

Feb 7

North America’s bats are dying in record numbers from white-nose syndrome, a deadly fungus which is spreading across the United States and into Canada.

Photo of Indiana bats hibernating

The Indiana bat, already classified as Endangered due to a range of threats, is one of the species most under threat from white-nose syndrome.

Greatest threat to bats 

First identified in 2006, white-nose syndrome is a fatal disease which infects the skin of hibernating bats, turning their snout frosty white. It is unclear exactly how the disease kills the bats, but it is thought to affect their ability to hibernate, causing infected bats to use up their fat reserves.

The disease has already killed over a million bats of at least six different species, including the Indiana bat, little brown myotis, gray myotis and cave bat. In some colonies it has had a shocking mortality rate of 95 percent. Alan Hicks of the New York State Department of Environmental Conservation has described white-nose syndrome as “the gravest threat to bats… ever seen”.

Photo of little brown myotis

The little brown myotis, another hibernating bat which has been affected by white-nose syndrome.

White-nose syndrome’s rapid spread

Since it was first discovered, white-nose syndrome has spread through bat colonies across the eastern United States, and several infected caves have also been identified in Canada. Without urgent action, the disease is likely to spread unchecked into the western states in what the U.S. Fish and Wildlife Service has called the worst wildlife health crisis in memory.

Photo of greater mouse-eared bat at the roost site

The greater mouse-eared bat is one of the European species found to be infected with white-nose syndrome.

The fungus believed to cause white-nose syndrome, Geomyces destructans, has also been recorded in at least five bat species in Europe, and there is evidence to suggest it was first transported to North America by humans. Although it has not yet caused widespread mortality of bats in Europe, it is unclear whether the situation will stay this way.

A deadly but little-known disease

Unfortunately, scientists still know very little about this worrying disease. Hibernating bats typically come together in large, tightly packed groups, which may increase the risk of cross-infection, and humans are also believed to spread white-nose syndrome between caves.

Photo of a pair of gray myotis bats in flight

The gray myotis, or grey bat, is listed as Near Threatened by the IUCN.

Whatever the answers, urgent action is clearly needed. A recent review published in Conservation Biology has called for the creation of a ‘road map’ to tackle the disease. It concluded that white-nose syndrome has “changed the focus of bat conservation in North America”, and that a national response is required. This may include monitoring and disease surveillance, active research into how to treat individual bats, and a programme of public education.

Others have also called for the urgent closure of caves and mines in the western United States, to prevent visitors from inadvertently helping this deadly fungus to spread even further.

Read The Independent article on this story.

View more bat species on ARKive.

Liz Shaw, ARKive Species Text Author

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