The Land Massive

Life is hard for wild animals, being fraught with the perils of predation, starvation and sickness. Only the strongest manage to survive into adulthood and breed, which means that only the best genes are passed into the next generation. This is the major driving force behind evolution and is responsible for the staggering diversity of life on our little planet.

One of the most obvious adaptations that some species have is their tendency to grow to enormous sizes. This is typically a defense against predators and takes advantage of the 'ten times larger' rule. Simply put, this rule states that a terrestrial animal becomes safe from predation if it can grow ten times heavier than their largest predator, since their predators are unable to develop jaws strong enough to kill them.

Obviously, this rule is not absolute. It doesn't take mankind in account, as our technology and sentience allowed us to overcome it as cavemen, nor does it take into account predators growing larger themselves. If all of the prey species in an area begin to grow larger, this will itself drive a size increase in predators. Bigger prey means more meat per kill, which is able to fuel more muscle mass and only the largest predators will be able to make kills (so only the genes for a bigger body size will be passed down into subsequent generations).

This means that predators and prey are locked in a constant arms race where each is trying to become bigger. Over time, the size of each species will grow bigger until size becomes limited by another factor - such as the availability of food - and is therefore no longer advantageous (where upon it's selected against and a 'maximum' size of the species has been reached).

Animals have reached unbelievable sizes in the past, both in the oceans and on land. Dinosaurs are the obvious example of megafauna, with some species becoming so heavy that the ground used to tremble as they walked! Sadly, there aren't animals this impressive anymore (certainly not on land, anyway), but we do have some truly huge beasts roaming our continents. Here's a list of the top ten largest animals that are alive today (sorted by average weight):

10: Wild (Asian) water buffalo: 770kg/3.5m long (max weight: 1, 250kg)

Also called the Asian or Asiatic buffalo, the wild water buffalo, Bubalus arnee,  is endemic to Southeast Asia. As well as its obvious bulk, the bovid is famed for having the widest horn-span in its family, which can be as wide as 2m from tip-to-tip in large males.

Wild water buffaloes are gregarious and live in tight, matriarchal groups as a defense against predators. Each group is called a 'clan' and is made up from related females and their young offspring. A clan can be as large as 30 individuals and often band together with other clans to form large herds (for further defense) that can consist of more than 500 individuals!

To avoid inbreeding, young males actually leave their clan once they become sexually mature and form small 'bachelor' groups. These groups consist of about 10 males and generally spend the dry season away from females. In breeding season, the young males rejoin a herd where they are polygynous and mate with multiple females.

9: Black rhino: 1, 150kg/3.5m long (max weight: 1, 900kg)

Black rhinos have two horns on their snout, which are made from keratin - the same protein as hair and nails. Their horns can grow as much as 3 inches a year and individuals have been found with horns that are longer than five feet! Sadly, their horns have been their downfall as it is coveted for Asian herbal medicines and ornaments in the Middle East, meaning that the black rhino is now classified as 'Endangered' by the IUCN.

There are four species of black rhinos (of the genus Diceros), which are actually grey. Their skin looks darker because they frequently wallow in mud to help keep cool through the hottest parts of the African day. Their size and rotund shape means that they actually retain body heat, so black rhinos are usually inactive during the hottest hours and rest beneath shade if the cannot find shallow water. During gloaming, when it's cooler, the rhinos feed by browsing shrubs and the lower branches of trees.

8: Walrus: 1, 200kg/3.4m long (max weight: 2, 150kg)

Odobenus rosmarus - the Latin taxonomic name for the walrus - literally means "tooth-walking sea-horse". This name stems from the tendency of walrus' to drag themselves onto pack ice using their tusks for purchase. It should be noted, however, that walrus tusks are actually elongated canines. These teeth are so large that they can grow as long as 1 meter in big males!

Walrus' are found throughout the Northern Hemisphere in the Arctic Circle and some subarctic regions. Walrus' once covered most of the frigid north, but their numbers were decimated by hunting in the 19th Century and their populations are now discontinuous; being limited to certain regions. That being said, they can still be found through most areas of shallow water, where they like to dive and crawl across the bottom of the sea bed to feed off crustaceans, molluscs, amphipods and slow-moving fish.

7: Giraffe: 1, 400kg/6m tall (max weight: 2, 150kg)

There are nine distinct species of giraffe, which are classified under the genus Giraffa. Growing to heights of 5 - 6m, giraffes are the tallest living animal and have unique patterns of spots in their fur. Their spotting is very similar to human fingerprints and can used to identify an individual. Interestingly, their spots also reveal the relative age of a giraffe as they grow darker as throughout their lives.

Giraffes are herbivores and use their long necks to reach leaves that are high up in the canopies of trees. This allows them to access food that many animals are unable to get at, thus allowing them to exploit a very specific niche. Despite this being an obvious use of their long neck, many scientists are skeptical that this is why it first evolved. Their neck is simply too exaggerated for access to slightly more food to have driven its appearance and many scientists now believe that the length of their neck was initially a sexually selected trait.

During mating season, male giraffes fight for the right to mate with females. They have an interesting way of dueling called 'clubbing', where they literally use their heads as bludgeons to strike their opponent with. As explained by the mechanisms of physics, a giraffe's head will hit harder the longer its neck is. Thus, having a longer neck would have given a giraffe an advantage in battle, meaning that it is more likely to win and pass on the 'long neck' gene so becomes selected for. Being able to reach an abundance of previously unattainable food would have then acted as a secondary use of their long necks and would have helped to reinforce its selection.

6: Gaur: 1, 600kg/4m long

Gaur, Bos gaurus, are characterised by a very prominent dorsal hump and have a long dewlap that hangs from their chin. Other than mankind and tigers, their large size means that they are rarely preyed upon and their lives are relatively safe for a herbivore.

Gaur are typically diurnal, gregarious animals where the females live matriarchal herds with their close relatives and offspring. To avoid inbreeding, a young male leaves its herd once it has sexually matured and spends much of the year in solitude. During the breeding season, polygynous males rejoin herds where they compete for mates by showcasing their size and emitting loud calls. 

Interestingly, scientists have noticed that many gaur become nocturnal in areas with high levels of human activity. But whatever hours gaur keep, their behaviour remains the same and they seem to actively avoid water, going to sources only sparingly to drink. They rarely wash or wallow and spend much of their time browsing on a wide variety of shrubs, flowers and grasses. 

5: Hippopotamus: 2, 500kg/1.2m long (max weight: 3, 400kg)

The hide of the hippopotamus, Hippopotamus amphibius, is so thick it can make as much as a half a ton in large males! Interestingly for an animal that lives in an extremely hot environment, hippos have neither sweat nor sebaceous glands. Instead, they have unique glands that secrete a viscous red fluid. This has given rise to the urban myth that hippos 'sweat blood'.

Due to their weight, which makes them cumbersome and ungainly on land, hippos spend much of their time in water where their body weight is decreased. Hippos mainly venture onto land to feed at night, where they are able to climb even very steep banks in their search for grass. Most hippo attacks on humans happen during the night, when a person accidentally walks between the hippo and water. The hippo panics and then charges, bulling over the person as it tries to get back to safety.

Hippos are actually the most dangerous animal to humans in Africa and should be avoided if ever seen in the wild. They are extremely territorial and (in addition to what was mentioned above) may attack people on shores and knock us from boats if we venture into their 'space of water'. With hugely powerful jaws that can open almost 180 degrees, hippos are reportedly able to bite animals as big as Nile crocodiles clean in half with a single bite!

4: White rhino: 2, 350kg/3.8m long (max weight: 3, 850kg)

The white rhino, Ceratotherium simum, spends large amounts of its day wallowing in the wet mud around rivers, streams and lakes. The mud acts as a natural 'sun cream' and helps to deter parasitic insects.

Unlike their cousins, black rhinos, white rhinos are grazers and have differently shaped mouths that are adapted to trimming grass off the ground. They have poor eyesight, but have excellent hearing and even better smell. Due to this, they often walk in single file so they can follow the scent trail of the rhino ahead of them.

3: Southern elephant Seal: 3, 000kg/5m long (max weight: 4, 000kg)

There are actually two types of elephant seal, but it is the southern elephant seal, Mirounga leonina, that grows the largest. Surprisingly, their name does not stem from their enormous size, but rather from their inflatable trunk-like snouts!

Living in the brutal Antarctic waters, Southern elephant seals are superb divers and can go as deep as 1.5 miles, staying submerged for up to 2 hours at a time. While underwater, southern elephant seals hunt fish and squid, which form the staples of their diet. Both male and female seals spend months at sea at a time, where they migrate vast distances in search of food.

Elephant seals return to rookeries during their breeding season, where males compete with each in other in brutally violent displays for the right to mate with females. Successful males can form harems that consist of 40 - 50 females, whom they mate with exclusively!

2: Asian elephant: 4, 200kg/6m long (max weight: 5, 200kg)

Like their African cousins, the Asian elephant, Elephas maximus, has an extremely long gestation period and their pregnancies last for 22 months! Although this isn't surprising really, considering newborn calves can weight as much as 90kg!

Asian elephants have been domesticated by humans over thousands of years for a variety of tasks. Most often, the elephants are used to carry or move heavy objects and as taxis, where they carry people around on saddles or carriages called howdahs. Less commonly, but perhaps more famously, the elephants have been used for combat on occasion by warlords such as Hannibal, who took the elephants over the Pyrenees and the Alps in his campaign against the Roman Empire!

1: African  elephant: 8, 500kg/6.7m long (max weight: 13, 000kg)

Although African elephants are noticeably bigger than their Asian cousins, you can also use the shape of their ears to tell them apart. Rather bizarrely, the shape of an African elephant's ear looks similar to the continent of Africa, while the shape of an Indian elephant's ear looks a bit like India! 

There are actually two types of African elephant of the genus Loxodonta: the African bush elephant and the slightly smaller African forest elephant. Both are larger than the Asian elephant and can roam huge distances in search of food. The elephants eat roots, grasses, fruit and bark, which they attain using their deceptively dextile trunk and their tusks, which they use for scraping trees and digging.

Unfortunately, as with Asian elephants, their trunks have also proved to be their downfall and they were almost hunted almost to extinction by those in the ivory trade. Since the international trading ban on ivory that was placed in 1990, elephant numbers have recovered somewhat (although illegal poaching is still a problem). It's estimated that there are now as few as 700, 000 elephants left in Africa and they are officially classified as 'threatened' by the IUCN. Sadly, less than 20% of the elephants' known range is under formal protection (which is largely due to budget constraints and the instability of many Africa governments). 

Face off: the great white shark vs the killer whale

Our oceans are full of predators, ranging from tiny carnivorous fish to poisonous snakes; from poisonous snakes to electrocuting eels; from electrocuting eels to murderous dolphins. In short, predators are everywhere and none are more feared than the great white shark and the killer whale. Both of these animals are titans – huge animals that can hunt and kill almost anything they want to (and yes, humans are included). But which of these is the top predator? Which of them would best the other in a fight?

The great white shark, Carcharodon carcharias, is one of the most feared animals in the oceans. The sharks often hunt by taking advantage of their huge strength, ambushing the seals they hunt from underneath while they rest on the surface. Unfortunately, surfers resting on their boards can look very similar to seals from underwater, which is believed to be the main cause of great white shark attacks on humans.

I’m sure many of you are thinking that this would be the great white. And why not? Great whites have been known to kill humans and there is a huge ‘fear culture’ around sharks after Peter Benchley’s Jaws was televised in a film. You would be wrong, however, and there is a case that to show that it is in fact orcas that rule the oceans.

In the first instance, you have to remember that orcas are social and hunt in packs (which has actually earned them the nickname of ‘the wolves of the sea’). Obviously, this provides killer whales with a huge advantage over the solitary great white and orcas can bring down prey much larger than themselves. In fact, orcas have even been known to go after small female sperm whales (which are actually the largest predator alive), so picking off a lone great white shouldn't be too much of a problem for them!

Like humans and other primates, killer whales are extremely social and live most of their lives in tight-knit social groups of close family members. To prevent the inbreeding that this would inevitably lead to, male orcas usually leave their maternal pod once they sexually mature and actively seek another pod to live with for the rest of their adult lives.

Secondly, you have to consider the intelligence of killer whales, which are part of the same family of oceanic dolphins (Delphinidae). All of the members in this family are extremely resourceful and have been seen to use complex, highly sophisticated tactics while hunting their prey. In fact, killer whales have actually been observed practicing to hunt (click here for more information) and it is one such tactic that leaves little doubt that orcas are hierarchically above great whites.

As you may or may not already be aware, orcas have different cultures (in much the same way as humans do) and different pods in various locations around the world specialise in hunting certain animals. Common examples of their sources of prey include fish and water mammals, such as seals. But it is the pods that specialise in hunting sharks that are really relevant for this post. Such orcas have realised and taken advantage of two very simple aspects of shark anatomy:

• Firstly, most species of shark go into a hypnotic state of sleep called tonic immobility when they are turned upside down
• Secondly, sharks have to keep swimming in order to breathe and, as soon as they stop moving, water ceases flowing through their gills and they begin to suffocate

Since great white sharks have to keep swimming in order to breathe, they have developed a remarkable method of sleep where they rest each half of their brain separately. This allows the neurotransmitters in their brain to recover to normal levels after waking activity, while simultaneously allowing the shark to keep moving and remain alert for prey and danger.

By taking advantage of these two simple facts, orcas can kill sharks extremely easily and with very little risk of injury to themselves (i.e. the sharks can’t fight back). To do this, orcas take advantage of their extreme agility and ambush sharks from above. As they near the unassuming shark, they bite it just above their dorsal fin and use their strength and body weight to roll the shark upside down, meaning that it falls asleep and stops struggling. Then, it’s just a simple case of the killer whale holding its breath while it waits for the shark to suffocate and die!

This tactic is merciless and brutal, but it is extremely effective and scientists have actually seen killer whales using it on great whites off the coast of California! What is also interesting, other than orcas being able to kill great whites so easily that is, is that great whites (like many species of shark) release chemicals called ‘death signals’ into the water when they are killed. These signals drive off all other great whites for miles and, for many years, scientists were baffled by why the massive predator suddenly vanished from Californian waters. It was only when they realised that the exodus of great whites coincided with the seasonal arrival of a certain pod of orcas from Antarctica that they put two and two together and began to observe how the two predators interacted. Just imagine their surprise!

Antlions: the truth behind Star Wars

Anyone who has ever seen The Return of the Jedi will be familiar with Luke Skywalker’s and Han Solo’s plight as Jabba the Hutt attempts to feed them to the sarlacc, which lurks in the bottom of the Great Pit of Carkoon. What might surprise you though is this isn’t far from the truth and many insects live in very real danger of coming face-to-face with such a creature, which is known as the antlion. 

As their comparison to the fictitious sarlacc suggests, antlions are ambush predators and are fairly common worldwide. In fact, they are found in almost every dry, arid environment and around 2, 000 species have been described so far that belong to the family Myrmeleontidae. Like many insects, antlions have a complex life cycle and pass through a larval form before they finally mature into adults. Due to this, the term ‘antlion’ is usually reserved to the larval form of the insect (which are sometimes called doodlebugs due to the spiralling trails they leave in sand while looking for a suitable place to build their trap), as an quick way to identify the form of the insect. 

Just like the sarlacc is, antlions are terrors and are capable of eating almost any arthropod that is unlucky enough to fall into one of their traps. Thus, their diet consists of a variety of insects that ranges from ants (obviously) and termites to small spiders! How their prey is caught however, depends on the exact species of antlion and their surrounding habitat, meaning that they could be lurking in foliage, hiding in the cracks in rocks and bark or be waiting in especially dug pits. 

Unusually among insects, antlions lack an anus and store all of their waste inside their bodies until they undergo metamorphosis (where it is discarded with the remnants of their cocoon).

It is the species that dig pitfall traps in sand that are particularly renowned however, and much research has been carried out into their trap-building behaviour. Typically, antlion pitfall traps are about 3 inches wide, 2 inches deep and are dug in finely grained, loosely packed sand. This criteria allows an antlion to create a steep, treacherous pitfall that their prey struggle to escape from once they've fallen into it as the walls crumble beneath their feet. To make their escape even harder, the antlion will then toss sand at the struggling insect to create a mini ‘landslide’ that helps to drag the struggling insect further into the hole. 

And once the insect has reached the bottom of the pit, it's all but game over and the antlion grabs it in its powerful mandibles, injecting deadly toxins and acids into its prey via several long spines that project from its hollow jaws. The antlion, which is firmly anchored in its trap by forward-facing bristles on its legs and body (that prevent it being dislodged and pulled from the pit), then holds its prey still until it has died and sucks the fluid ‘mush’ from the insect - feeding in same grotesque manner as spiders do. And, once the antlion is full, it throws the withered husk of its prey from its trap in the same way as it tosses sand and sets about repairing its walls. 

Antlions can remain in this larval form for up to 3 years, depending of course on the exact species and the amount of prey that is available, before they encase themselves in a cocoon of silk underground. Here, antlions undergo a remarkable process called metamorphosis where they change into their large, adult form over the period of about a month. Once their transformation has finished, the insects emerge from the ground, wait for their bodies to dry out and harden, and take to the air in search of mates.

Depending on the species, antlion damselflies can vary from being fairly small with 2cm wingspans to being much larger with wingspans of 15cm! Adults are much bigger than the larval form and show the greatest difference in size in any holometabolous insect (one that completely changes form via metamorphosis).

Adult antlions are sometimes are sometimes called antlion damselflies (despite having no relation to the damselfly family), and, depending on the species, vary between remaining as fierce predators or switch their diet to eat pollen and nectar. As their nickname suggests, the adult form look similar to damselflies although they can easily be identified by their extremely long, clubbed antennae and very narrow wings. 

Oddly, antlion damselflies are rarely seen in nature because they are usually active in the late evening and are poor flyers so (rather ironically), are very vulnerable to predators. They can be a real nuisance in desert areas however, where they are more abundant, as they tend to swarm and can deliver a mildly painful bite to any humans that they land on!

So, you might agree then that antlions are interesting insects in their own rights - being such fierce and efficient predators - but, considering they are the inspiration behind one of Star Wars' most famous aliens, they become even cooler and are definitely well worth knowing about!

Beneath the trapdoor danger lurks...

Wherever you go, you are bound to find spiders. They are an ancient class of predator and have learnt to use poisons, brute force and complex webs of silk to terrorise and instil fear into animals on every continent of the world except Antarctica. 

Typically, an easy way to tell the rough age of a species of spider is by looking at the complexity of the web it spins and the general rule is that the more elaborate the web, the younger the species of spider. This makes sense really as it would be expected for more complex structures, such as web scaffolding patterns, to take longer to evolve! Thus, the infamous tarantulas, which use silk only to line their burrows for warmth, are among of the oldest species of spider on the planet. 

Trapdoor spiders are another ancient lineage of arachnid, which is suggested by the simple manner in which they use silk. They use silk for the same purpose as many more ‘modern’ spiders since they rely on it to convey vibrations to them to show that prey is nearby, but do not spin it into complex webs. 

There are more than 500 different species of trapdoor spider that have been described so far, which can be found in tropical regions all across Earth. Despite being large and looking fairly intimidating, trapdoor spiders are rarely aggressive and are not dangerous to humans.

So instead of building silk nets like many newer species, trapdoor spiders dig a deep burrow in the soil (some species make a long tube of silk instead) and spin trip-lines that radiate out from the tunnel’s entrance. The spider then lurks near the mouth of its burrow, touching its trip-lines, and waits for an insect to knock one of the threads. When this happens, the spider feels the vibration and lunges out to grab, bite and poison its prey. 

Many species of trapdoor spider take this ambush tactic a step further and actually build a covering over the hole of their tunnel. This ‘trapdoor’ is what gives the family of spiders its name and is cleverly made from materials surrounding the burrow, such as soil, vegetation and silk, so it is camouflaged perfectly with the ground! 

Species that make a trapdoor always hinge their covering at one end with thick webbing and hold it down tightly using special claws on the ends of their feet. When its trip-lines are activated, the spider flips open its trapdoor, explodes out of its burrow and drags the hapless insect back inside for its dinner! And because trapdoors are typically very large spiders, almost all insects are on their menu – with meals commonly including cockroaches, crickets, grasshoppers, beetles, moths and other spiders. 

As would be expected, trapdoor spiders invest such a huge amount of time and energy in digging their burrows that they are a very shy and reclusive species. In fact, trapdoors rarely leave their burrows at all and female spiders typically spend their full 20 year lifespan in one burrow! It is usually only males that venture out from their burrows and even then, only once they have matured sexually and are seeking a mate. Like all spiders, male trapdoors mature near to the end of their lives (which are much shorter than those of females) so are inclined to take huge risks in finding a mate before they die. 

Once a male spider has mated with a viable female, the male dies (often to be eaten by the female) and the female remains in her burrow to feed her spiderlings when they hatch. Shortly after hatching, the spiderlings venture out of their mother’s burrow to dig their own home using their front legs and specialised barbs on their fangs called rastellum that help them to move soil.

Lyes of attraction

Except for the occasional white lie here and there, most of us try to avoid deceiving our families and friends and dislike being lied to by others. Lying is not considered a positive trait and people who tell fibs too often are mistrusted and usually find that they have fewer friends than they thought they did.

As you undoubtedly know, lying is a particularly huge issue in relationships and has probably broken up more couples over human history than we can record. This comes as no surprise and dumped liars rarely receive sympathy as we all know that it's their own fault. What is odd though, is that not all animals share our views on lying and for one species in particular, the Australian lyrebird, the better an individual can lie the more popular they are!

Lyrebirds are among the most esteemed of Australia's native animals and are famous for their impressive prowess of 'lying'.  There are just 2 species of lyrebird: the superb lyrebird (Menura novaehollandiae) that is pictured above and Albert's lyrebird (Menura alberti), which belong to their own unique genus.

In fact, being able to lie well is much more important than simply for making an individual popular - it is an essential skill that a male bird must master if he wants to attract a mate! Lyrebirds, you see, have one of the most sophisticated courtship rituals in nature, which involves splaying their luxurious tail feathers (in much the same way as a peacock), and mimicking as many noises as they possibly can. These sounds, which can be imitations of anything, such as other bird calls, car alarms and even chainsaws felling trees, are then incorporated into an elaborate song that the male may sing for up to 4 hours a day during breeding season (June to August)!

It appears that the more complex the courtship song, the more successful the male bird is in attracting a mate. Once a male lyrebird has successfully mated with a female bird, she lays a single egg in a nest that she's made on the ground, and incubates it as the sole parent for nearly 2 months.

Analysis of the songs made by courting lyrebirds has found that they are usually split into 7 clearly distinct sections, where about 80% of the entire song is made from mimicry. Male and female lyrebirds both become sexually mature before they are 10 years old, although it should be noted that females mature a few years earlier than males do. Due to this, male birds don't actually start singing properly until they are almost a decade old. Before then, males are believed to practise 'lying' where they learn to modulate their highly developed voice box so that it can mimic almost any sound they hear.

Thus, the ability to lie and produce a whole host of sounds that are not normally made by lyrebirds is a huge part of their culture and has made the passerine (song) birds one of the most noted birds in Australia, and maybe even in the world.

Mouse plagues: the terror of Australia

In 1993, south Australia was assaulted with a plague of mice. Sounds ridiculous doesn't it? But when half a billion field mice rise up in the spring to destroy your crops and eat your livestock alive, then no-one's laughing... And this is exactly what happened.

The common field mouse, Apodemus sylvaticus, is the culprit of the regular mouse plagues in Australia. The mouse, originating in Asia, was spread around the world as a stow-a-way on-board merchant trading ships.

The 1993 assault was Australia's largest recorded mouse plague and an estimated 500, 000 tons of wheat was destroyed by the rodents over the plague's 6 month duration, which is enough to feed the entire state of Utah (USA) for 4 years! The mental trauma of the plague and the loss in the livelihood of farmers was enough to drive at least 6 people to suicide and many farmers chose to abandon their livelihood and leave the at-risk areas in the south, for good.

Surprisingly, mouse plagues are fairly common in Australia and on average, happen about once a decade. (Australia suffered its most recent mouse plague last year, although it was nowhere near as large as the one in 1993). They typically erupt after a period of very wet weather that causes a 'bumper' harvest, which provides enough food for the mice to allow their populations to grow to enormous sizes. This, coupled with the fact that field mice living in Australia have very few natural predators, suffer from only a handful of the diseases that are endemic to their European cousins and have a very rampant sex life, means that their populations can grow to ridiculous sizes in a very short space of time. In fact, it has been estimated than one mouse and all of her offspring can produce 3, 000 new mice in a single year: a single pair can have babies every 3 weeks, producing an estimated 500 young in 5 months; babies that can then breed themselves at just 5 weeks old!

A pile of field mice that were poisoned by Australian farmers during the mouse plague of 1917. Although mice plagues are rare elsewhere in the world now, evidence suggests that have blighted humans throughout our history. Aristotle wrote about them 2, 351 years ago and they have even been mentioned in the Bible, in the First Book of Samuel.

As previously said, such large populations of mice are extremely destructive and consequently, farmers go to huge lengths to eradicate them in order to protect their crops and livestock. These techniques range from many simple (but not very effective) 'old-school' traps such as drowning mice in troughs full of water and leaving tarpaulins tied to the ground. During the day, field mice will hide beneath these tarpaulins, a fact that farmers have traditionally taken advantage of, using many inhumane methods like crushing and fire to kill the pests. Poisons are another, much more effective way to kill mice and are now laced over grain during mouse plagues. Poisons are usually sufficient to end mouse plagues, turning previously swarming land into killing fields. In 1993, 35 million mice were killed in just 1 month after poison was used (which reportedly hardly even dented their numbers) and one farmer claimed to be removing 70, 000 dead mice a day from his property.

Even without poisoning the plagues would eventually burn themselves out anyway, as such incredibly high numbers of field mice means that diseases spread throughout their populations like wildfire and they will eventually use up all of their available resources, meaning that they will starve to death. However, this won't be before they cause billions of dollars worth of loss to the Australian economy, so their government must still invest in expensive poisons (which also kill other native wildlife so are a last-resort weapon) in order to control the situation.

Despite being a fairly common occurrence in Australia, mice plagues cause huge amounts of damage and are very hard to control for in advance, mainly due to their unpredictability. They are incredibly damaging to the country's economy, to individual farmers' livelihoods and to local peoples' mental health! So all-in-all, are a real menace. Fortunately though, mouse plagues can be controlled and after human intervention their populations crash, with only an estimated 2 mice out of every 1, 000 surviving the cull...

Life's so short so I'm so fast

The Peregrine Falcon is a large, crow-sized bird of prey that is renown for its exceptional in-flight capabilities: the bird is incredibly agile and is the fastest known animal, entering dives of over 200mph whilst hunting! The Peregrine is also the world's most widespread raptor, being found on every ice-free landmass except New Zealand and can flourish in almost every ecosystem other than extreme polar regions, very high mountain ranges and areas of dense vegetation such as in tropical rainforests.

Peregrine Falcons have long, broad wings that end in points, the physics of which allows the bird great manoeuvrability, whilst simultaneously allowing them to reach very high speeds. Their wing-span can be a large as 47 inches and their typical body length is between 13-23 inches. Like many birds of prey, Peregrines show reverse sexual dimorphism and female falcons can be as much as 30 times more massive than males. Peregrines become sexually mature when they are a year old and mate with one partner for their entire life (unless their partner is killed), which is usually around 15 years. The falcons also use the same scrape nest for many years, which unfortunately means that their breeding habits are easily disrupted by anthropogenic activities and if their nest is disturbed, it may be a few years before the pair breeds again.

The Pergrine Falcon, Falco peregrinus. This photo shows the characteristic black 'moustache' of the bird that descends either side of its beak. Their moustache is often used by birdwatchers to quickly identify the bird. The Peregrines upper beak is notches near to its tip, which is an adaptation that allows them to kill prey by severing their spinal column at their neck.

Peregrines predominately eat medium-sized birds such as pigeons and small ducks, but will also occasionally hunt small mammals, reptiles and even insects when their preferred food sources are scarce. Like all falcons, Peregrines specialise in hunting prey whilst it is in-flight, which is where their manoeuvrability becomes useful as well as their extreme speed. When hunting, the falcons will soar to an extreme height until they locate a potential meal. Once they have locked onto a bird they enter a ridiculously steep dive, called a hunting stoop, where they reach incredible speeds of over 200mph. To-date, the fastest recorded dive of a Peregrine is 242mph! Dropping like a missile, the falcon aims to clip one of the wings of its prey, the force of which often kills the unlucky bird outright. Even if the bird does survive the impact however, its fragile wing will be shattered and it will fall to its death. The Peregrine then simply finds where the bird has landed and tucks in...

A Peregrine Falcon entering its hunting stoop. The bird pulls its wings in tightly against its body and will drop at an almost vertical trajectory. Third eyelids, called nictitating eyelids, shut during the dive to protect the bird's eyes and specialised bony tubercles on its nostrils prevent much of the airflow from entering its lungs, preventing them from bursting due to the high-pressure air that is flowing into them.

The speed and spectacular hunting techniques of the Peregrine Falcon has long made the bird of interest to humans and the bird has historically been associated with aggression and martial powers. In Europe for example, Peregrines were the hierarchical bird of prey associated with princes, just below the Gyrfalcon that was used by kings, and princes often used the falcon for hunting and as a display of status. Native American Indians also used the raptor as a symbol of status, along with various other birds of prey, as a representation of celestial power and men of high status were often buried in costumes of such birds.

Man's interest in the Peregrine has also meant that it has been heavily sought after for falconry for more than 3, 000 years and the bird is frequently used in shows and by experienced falconers due to the high speeds of its dives.

A Peregrine Falcon featured on the quarter for the state of Idaho, USA.

Unfortunately, the high human interest in the bird has meant that historically, it was vulnerable to egg poaching. This, along with their persecution by farmers and their susceptibility to many pesticides such as DDT, meant that the numbers of Peregrines decreased dramatically throughout the mid- to late- 20th Century and bird was once classified as an endangered species by the IUCN. However, although the interest of humans in the Peregrine was part of its downfall, it is also the bird's saving grace and the recovery of the bird has been very successful. This is mainly due to the large numbers of the bird that were kept in captivity for their use in falconry, which enabled conservation biologists to mount a large-scale breeding program and the species has responded well, with an increase in Peregrine populations worldwide. There are now an estimated 1, 400 breeding pairs of Peregrine Falcons in the UK and in 1999, the bird was removed from the US Endangered Species List.