What Wombats Leave Behind

wombat

Wombats are furry marsupials endemic to Australia. (Photo credit: covenant/Shutterstock)

Let’s be honest, poop is kind of gross. It’s not something normally discussed in polite company. Yet, we can all agree it serves a purpose. Beyond the obvious purpose of eliminating wastes, what organisms excrete also can help both human and animal doctors diagnose illnesses and assess the general health of a patient. In the wild, “scat,” as it’s often referred to, has even greater significance. [Read more…]

A Breath of Fresh Fructose?

naked mole rat

Described by some as looking like “bratwurst with teeth,” naked mole rats live in communities with social structures resembling beehives, are coldblooded like reptiles, and now are known to get energy from fructose, like a plant. (Photo credit: Ger Bosma/Alamy)

It’s difficult to find an odder animal than the naked mole rat (Heterosphalus glaber). A native of east African deserts, these mammals live more like bees, in complex, underground societies complete with a queen who gives birth to worker offspring who will never reproduce.  [Read more…]

Convinced Your Dog is Smart? You Might Be Right

guide dog

Humans have long recognized the alertness, trainability, and friendly temperament of many dog breeds and pressed them into service for such very personal tasks as serving as trusted guides for the visually impaired. New research out of Hungary shows that dogs may possess an even more beautiful mind the previously thought.(Photo credit: bobbymn/iStockphoto.com)

If you have a dog, you probably think yours is the smartest dog in the world. New research from Hungary just may prove you’re correct. [Read more…]

Sleep Like A Dolphin

dolphin

A dolphin rests with one eye closed. (Photo credit: urosr/Shutterstock)

Has this ever happened to you? You finally arrive at your destination, ready to get a good night’s sleep so you can begin your vacation, and then you find … you simply can’t seem to get a good night’s sleep. It’s not you. It’s a phenomenon sleep researchers have long known about, called the “first-night effect” or FNE.

[Read more…]

Do You Smell a Rat … Or Should the Rat Smell You?

African giant pouched rat

Some animals, such as this African giant pouched rat, are being used to sniff out disease in humans. (Photo credit: Penny Boyd/Alamy Stock Photo)

In 1989, a paper appearing in the British medical journal The Lancet made an astounding claim. Two dermatologists reported how a patient decided to come in for an exam because her dog kept sniffing a mole on her leg. The dog even tried to bite it off at one point. Tests proved it was a malignant melanoma nearly two millimeters thick. When removed, the woman survived, and the study would eventually become known as the ‘First Lancet Letter’ or the first time in a peer-reviewed medical journal that an animal’s senses had been linked to the detection of disease. [Read more…]

Revamping the Reputation of the Vampire Bat

vampire bat

Scientific studies indicate that the much-maligned vampire bat may hold the key for treating heart disease and strokes. (Photo credit: Kozoriz Yuriy/Shutterstock)

For many centuries, people have associated bats with eerie places. Perhaps its because most bats appear primarily at night and seem to move stealthily in the dark. [Read more…]

What Does the Fox Say? and Other Tales of Animal Communication

fox

What does the fox say? (Photo credit: Kevin Law of London, England/Flickr/Getty Images)

In the lyrics of a recent popular song, listeners are asked “What does the fox say?” [Read more…]

Dragon With A Deadly Bite

The Komodo dragon, like its name suggests, is a ferocious animal. It is the largest lizard in the world–as an adult it may grow to a length of ten feet and weigh over 150 pounds. In addition to its menacing size, the Komodo dragon also features super-sharp teeth and claws. If the teeth and claws don’t kill its prey, blood poisoning caused by one of the 50 bacteria species in its saliva will.

The komodo dragon is a reptile endemic to Indonesia. (Photo credit: Wolfgang Kaehler/Alamy)

Natural History

The Komodo dragon is the worlds largest living lizard. Male lizards can grow up to ten feet in length and weigh around 200 pounds. Females tend to be slightly shorter (growing to a length of eight feet) and weigh around 150 pounds. These unusual lizards live in the lower dry forest and savanna habitats of four volcanic islands (Komodo, Gila Montang, Rinca, and Flores) within Indonesias Lesser Sundra Islands. The population of komodo dragons across these four islands is estimated to be between 3000 and 4000 individual animals. Komodo dragons are considered to be an endangered species due to factors including the loss of adequate habitat, poaching, and natural disasters.

Though some female Komodo dragons have been known to reproduce asexually, that is, they are able to fertilize their own eggs, most Komodo dragons reproduce by sexual means. The lizards mate between the months of May and August. Male lizards wrestle together to gain access to females. Following a victory, a male Komodo dragon mates with a female, fertilizing her eggs. In September, the female lizard lays a clutch of between 20 and 30 eggs into a nest. The female then incubates the eggs for a period of seven to nine months. Upon hatching, the young Komodo dragons have to fend for themselves, and many do not survive to adulthood.

Ambush Predator

In addition to their formidable size, Komodo dragons also have a ferocious bite. A Komodo dragons mouth is filled with 60 serrated, shark-like teeth that are able to tear chunks of flesh out of its prey when feeding. The teeth are embedded within its gums. When it begins to feed, the lizards gums begin to bleed, meaning feeding time can be a particularly gruesome sight. In addition, the Komodo dragon has a flexible skull, which lets it swallow large hunks of food at one time.

The komodo dragon’s serrated teeth pop out of its gums when it is ready to feed. (Photo credit: Anna Yu/Getty Images)

Like crocodiles, komodo dragons are ambush predators. When ready for a meal, the lizards lie in wait, and spring upon their unsuspecting prey in a violent maelstrom of super-sharp teeth and claws. Even if a prey item is somehow able to survive the initial attack, it most likely will die soon after due to blood poisoning–a komodo dragon harbors over 50 different strains of bacteria in its mouth. Komodo dragons have a keen sense of smell and have been known to track the presence and direction of a kill as far as 2.5 miles away. These reptiles detect odors like a snake. A Komodo dragon uses its long, forked tongue to gather particles from the air. Next the lizard moves its tongue against its Jacobson’s organ, a sensory receptor located in the roof of its mouth, to identify airborne molecules.

A Komodo dragon is an indiscriminate eater–it eats nearly 90 percent of each kill it makes, including hooves, bones, and skin. It will also eat its prey’s intestines, first swinging them about to remove any fecal matter before chowing down. Komodo dragons are voracious eaters. In fact, a Komodo dragon tends to eat up to 80 percent of its body weight at one feeding. When young, Komodo dragons typically eat smaller items such as insects, birds, eggs, and small mammals. As adults, Komodo dragons have been known to eat deer, smaller pigs, water buffalo, and smaller Komodo dragons. At times, humans have also become a Komodo dragon’s prey. Though uncommon, four people have been killed by Komodo dragons since 1974, and eight people have been injured by the lizards in the previous decade.

A Venomous Bite?

Recent research indicates that there may be more than just virulent bacteria that kills a Komodo dragon’s prey. In 2006, Dr. Brian Fry and a colleague published a scientific study that indicated that some lizards may share with snakes the same gene responsible for venom production. Following an unfortunate outbreak of a deadly virus in a population of Komodo dragons held at the Singapore Zoo, Fry and his colleagues were able to collect specimens to study. The scientists discovered that Komodo dragons have a set of glands that make venomlike proteins. These proteins can cause a rapid drop in blood pressure and/or prevent blood from clotting. In a paper published recently in the Proceedings of the National Academy of Science, Fry and his fellow researchers conclude that when a Komodo dragon bites into its prey, it adds venom to the wound, which causes the prey to bleed uncontrollably and/or lose consciousness due to a rapid drop in blood pressure.

Not all scientists are convinced by this research, however, and find any compelling evidence lacking. Further research is required to determine if Komodo dragons truly pack some venom in their already deadly bite.

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Chameleon Spends Most of Its Life in Its Egg

“Life is short” isn’t just a witty saying for a certain species of chameleons that live in southwestern Madagascar. For the Labord’s chameleon (Furcifer labordi), life really is short. And, to make it even more interesting, the majority of its shortened life is spent within the confines of an egg. After hatching from its egg, the chameleon only lives another four or five months before its life is over.

An Accidental Discovery

The unusual natural history of these chameleons was discovered by researchers by accident. Kristopher Karsten, a graduate student based at Oklahoma State University, arrived late in the season. Although he expected to find many recently-hatched juvenile chameleons, he didn’t find any. Then, several months later in February, he discovered something even more unusual–the carcasses of many Labord’s chameleons, apparently dead from natural causes.

A male Labord’s chameleon. (Credit: Ken Preston-Mafham/PREMAPHOTOS/naturepl.com)

At the time of Karsten’s observations, not much was known about the life history of Labord’s chameleons. Since his initial observations, more than 400 individuals have been studied over a period of five field seasons and scientists now know much more about the species’ remarkable life history.

Shortest Lifespan, Fastest Growth Rate

Because of its short life span outside of the egg, it is imperative that the chameleon matures quickly–and that it does. Labord’s chameleons have the fastest growth rates of any tetrapod species. After hatching during Madagascar’s wet season in November, the chameleons grow at a rate of up to 2.6 mm (0.1 inches) per day. In fact, in less than two months, the chameleons increase in body size by 300-400 percent. To put that another way, if a human grew at the same rate, an infant that was 51 cm (20 inches) at birth would grow to a height of 1.5 meters (five ft.) over a period of only two months.

After reaching maturity, the chameleon population reproduces. Females dig burrows in the desert sand and bury their eggs about 138 mm (5.4 inches) below the surface. Following reproduction, all of the adult chameleons die. Meanwhile, the developing chameleons remain in their eggs underground for eight to nine months, where they wait out the dry season.

A female Labord’s chameleon. (Credit: PREMAPHOTOS/naturepl.com)

Ecological Constraints

So what accounts for such an unusual life history? Scientists point to several factors that may have led the species to evolve such a short lifespan. One factor is size–Labord’s chameleons are the smallest of its genus. Perhaps due to their size, the chameleons are a favorite snack of desert predators such as birds and snakes. A second factor is climate. The southwestern Madagascar desert climate where the chameleons live is harsh and unpredictable. In addition, the rainy season is short, which further limits the amount of time the chameleons have to grow and reproduce.

Questionable Future

Though scientists have learned a lot about Labord’s chameleons, many questions remain. While the short lifespan of the Labords chameleon lets it successfully survive the constraints of its ecology, scientists wonder how long-term changes in the climate–or even a short-term event like a longer-than-normal dry season–might affect the species.

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