An Animal A Day

last SG · 2005-03-09T00:11:15+00:00

Deepwater Arrowtooth Eel The Deepwater Arrowtooth Eel (Histiobranchus bathybius) is a cutthroat eel of the genus Histiobranchus, found around the world at d...

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Malayan Tapir

The Malayan Tapir (Tapirus indicus), also called the Asian Tapir, is the largest of the four species of tapir and the only one native to Asia. The scientific name is somewhat misleading, as the Tapirus indicus is not native to India.

Malayan Tapir, Tapirus indicus

General Appearance and Characteristics

The animal is easily identified by its markings, most notably the light-colored saddle which extends from its shoulders to its rump. The rest of its hair is black, except for the tips of its ears which, as with other tapirs, are rimmed with white. This pattern is for camouflage: the disrupted coloration makes it more difficult to recognize it as a tapir, and other animals may mistake it for a large rock rather than a form of prey when it is lying down to sleep.

Malayan Tapirs grow to between 6 and 8 feet (1.8 to 2.4 m) in length, stand 3 to 3.5 feet (90 to 107 cm) tall, and typically weigh between 550 and 700 pounds (250 to 320 kg), although they can weigh upwards of 900 pounds (410 kg) on occasion. The females are usually larger than the males. Like the other types of tapir, they have small stubby tails and long, flexible proboscises. They have four toes on each front foot and three toes on each back foot. The Malayan Tapir has rather poor eyesight but excellent hearing and sense of smell.

Lifecycle

The gestation period of the Malayan Tapir is approximately 400 days, after which a single offspring, weighing around 15 pounds (6.8 kg), is born. Young tapirs of all species have brown hair with white stripes and spots, a pattern with enables them to hide effectively in the dappled light of the forest. This baby coat fades into adult coloration between four and seven months after birth. Weaning occurs between between six and eight months of age, at which time the babies are nearly full-grown, and the animals reach sexual maturity around age three. Breeding typically occurs in April, May or June, and females generally produce one calf every two years. Malayan Tapirs can live up to 30 years, both in the wild and in zoos.

Behavior

Malayan Tapirs are primarily solitary creatures, marking out large tracts of land as their territory, though these areas usually overlap with those of other individuals. Tapirs mark out their territories by spraying urine on plants, and they often follow distinct paths which they have bulldozed through the undergrowth.

Exclusively vegetarian, the animal forages for the tender shoots and leaves of more than 100 species of plants (though it prefers around 30), moving slowly through the forest and pausing often to eat and note the scents left behind by other tapirs in the area. However, when threatened or frightened, the tapir can run quickly, despite its considerable bulk, and they can also defend themselves with their strong jaws and sharp teeth. Malayan Tapirs communicate with high-pitched squeaks and whistles. They usually prefer to live near water and often bathe and swim, and they are also able to climb steep slopes. Tapirs are mainly active at night, though they are not exclusively nocturnal. They tend to eat soon after sunset or before sunrise, and they will often nap in the middle of the night. This type of behavior characterizes them as crepuscular animals.

Habitat, Predation, and Vulnerability

The Malayan Tapir was once found throughout the tropical lowland rainforests of Southeast Asia, including Cambodia, Indonesia, Laos, Malaysia, Myanmar (Burma), Thailand, and Vietnam. Due to human activity, especially deforestation for agricultural purposes as well as poaching and illegal trade, its habitat and numbers have decreased in recent years and, like all tapirs, it is in danger of extinction.

Range of the Malayan Tapir

The species is officially recognized as Vulnerable under the 1996 IUCN Red List of Threatened Animals. The exact number of Malayan Tapirs left in the wild is unknown, but many scientists estimate that there are approximately 3,000 individuals left in the wild and 200 in zoos worldwide. Tapirs are rarely hunted by animals other than humans, because their tough skin and good defenses make it difficult to harm a healthy adult. Leopards and tigers may attack calves, old adults, or ill individuals, but for the most part the threat to tapirs comes from humans.

Conservation status: Vulnerable

Issue #48

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Common Starling

The Common Starling (Sturnus vulgaris) is a passerine bird in the family Sturnidae.

An immature female Common Starling, Sturnus vulgaris, in London

This starling is native to most of Eurasia, but has been introduced to South Africa, North America, Australia and New Zealand. This adaptable and omnivorous species has proved to be a pest in several of these countries. In Western Australia, which is starling-free, the government pays full-time hunters to patrol the border and shoot starlings as they arrive.

It is resident in southern and western Europe, but migrates from colder regions to these areas, and further south to Iberia (where it does not breed) and north Africa.

The Starling is catholic in its choice of habitats, and can be found in any reasonable open environment from farmland to saltmarsh.

These birds will eat almost anything, including farmland invertebrates and berries. This is a highly gregarious species, forming huge flocks in winter, and providing a spectacular sight as they descend into evening reed-bed roosts, often attracting birds of prey. Large roosts (exceptionally up to a million birds) can form in city centres, causing a great deal of mess from their droppings.

This is a hole-nesting species, and has impacted on native species where it has been introduced because of competition for nest sites.

This must be one of the most familiar of birds, with its shiny black plumage spangled with white. Confusion is only likely in Iberia in winter, when it has to be distinguished from the closely related Spotless Starling, which, as its name implies, has less spotting on its plumage. Adult males are less spotted below than adult females. Juveniles are dull brown, and by their first winter resemble adults but are browner especially on the head.

Starlings walk rather than hop. Their flight is quite strong and direct; they look triangular-winged and short-tailed in flight. In most of Europe, only the rarer and much paler Bohemian Waxwing shares this flight profile. This is a noisy bird, and a good mimic, like many of its family. In captivity, they are gregarious and love to imitate all types of sounds and speech, earning them the nickname "Poor-man's Myna". Information on care of Starlings as well as recordings of a Starling talking can be found at Starling Central.

Although there are approximately 200 million starlings in North America, they are all descendants of approximately 100 birds released in Central Park in the 1890s from Europeans. These starlings have created an evolutionary problem in North America since the starling prey has not adapted any type of defense instincts. This is what makes the European Starlings severely overpopulated and the birds can now be found all through North America and Alaska.

Issue #49

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American Crocodile

The American Crocodile (Crocodylus acutus) is the only New World crocodile and the top predator in its range.

American Crocodile, Crocodylus acutus, at Ding Darling reserve, Sanibel Island, Florida

Like all crocodiles it is a quadruped, with four short, splayed legs; a long, powerful tail; a scaly hide with rows of ossified scutes running down its back and tail; and mighty jaws. It has nictitating membranes to protect its eyes, and, despite the myths it does have lachyrmal glands, and can cleanse its eyes with tears.

The nostrils, eyes, and ears are situated on the top of its head, so the rest of the body can remain concealed underwater. The coloration also helps them hide.

American Crocodiles normally crawl along on their belly, but they can also "high walk". Smaller specimens can gallop, and even larger crocodiles are capable of surprising bursts of speed. They can swim equally fast by moving their body and tail in a sinuous fashion, but they can sustain this form of movement much longer.

They have a four-chambered heart, like a bird, which is especially efficient at oxygenating their blood. They normally dive for only a couple of minutes, but will stay underwater for up to 30 minutes if threatened, and if they remain inactive they can hold their breath for up to 2 hours. They have an ectothermic metabolism, so they can survive a long time between meals though when they do eat, they can eat up to half their body weight at a time.

Issue #50

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Leopard frog

Leopard frogs, which are also called meadow frogs and grass frogs, are a collection of so-called true frogs within the genus Rana. Once abundant in North America and Canada, their population has declined in recent years due to pollution and deforestation. Leopard frogs are often used as environmental indicator species because of their heightened sensitivity to chemical pollutants found in the air and water and are commonly used as dissection specimens in biology classrooms.

Green leopard frog, genus Rana, in a swamp with duckweed

Leopard frogs are recognized by their green or brown coloration with distinct light-edged dark spots across the back and pure white underside. They also have a characteristic line of raised glandular skin, called the dorsolateral ridge, extending from each eye to the groin. Some species also have a light marking on the center of their tympanic membrane. Males have two vocal sacs, located on both sides of the body, used to attract mates and establish territory. The adult ranges in size from about 5-11 cm (2-5 in) in length, depending on the species, with females generally larger than males.

Northern leopard frog

During mating season, the female lays 3,000-6,000 eggs, with each egg approximately 1.7 mm in diameter, in a large, flattened mass just below water surface. These eggs will attach to the pond substrate and one month after the eggs are laid, tadpoles emerge approximately 65-83 mm in length. The leopard frog will reach sexual maturity 2-3 years after eggs are laid and have a lifespan of 6-9 years.

Species of Leopard Frog

Rana berlandieri
Rana blairi
Rana chiricahuensis
Rana fisheri
Rana onca
Rana pipiens
Rana sphenocephala
Rana subaquavocalis
Rana yavapaiensis

Issue #51

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Magicicada

Magicicada is the genus of the 13- and 17-year periodical cicadas of eastern North America. These insects display a unique combination of long life cycles, periodicity, and mass emergences. They sometimes go by the common name "seventeen-year locust", but they are not locusts at all; locusts belong to the order Orthoptera.

A 17-year Periodical cicada

Taxonomy

There are seven recognized species. Three species have a 17-year cycle:

- M. cassini (Linnaeus, 1758)
- M. septendecim (Fisher)
- M. septendecula (Alexander and Moore, 1962)

Four more species follow a 13-year cycle:

- M. neotredecim (Marshall and Cooley, 2000)
- M. tredecim (Walsh and Riley, 1868)
- M. tredecassini (Alexander and Moore, 1962)
- M. tredecula (Alexander and Moore, 1962)

Generally, the 17-year cicadas are distributed more in the northern states of the eastern United States, while the 13-year cicadas occur in the southern states.

Description

Periodical cicadas are slightly smaller than other, annual cicadas. Imagines have a size of 2.5 to 3 cm (1 to 1.2 inches). They are black, with red eyes and yellow or orange stripes on the underside. The wings are translucent and have orange veins.

Magicicadas (both teneral and fully developed).

They are harmless animals; they neither bite nor sting. They are not poisonous, and there is no evidence that they transmit diseases. They generally do not pose a threat to vegetation, but young plants may be damaged by excessive feeding or egg laying. It is thus advised not to plant new trees or shrubs just before an emergence of the periodical cicadas. Mature plants usually do not suffer lasting damage even by a mass-emergence.

Broods

Periodical cicadas are grouped into thirty broods, based on the year they emerge. Broods are numbered using Roman numerals; broods I-XVII are the seventeen-year cicadas, while broods XVIII-XXX are the thirteen-year cicadas. Some broods are not known to exist, but they are retained in the numbering scheme for convenience.

Brood IX emerged in 2003. Brood X, a seventeen year brood stretching from New York to North Carolina on the East Coast to Illinois and Michigan, emerged in May 2004. Brood X is the largest of the broods of the periodical cicadas. No broods are expected to emerge in 2005 or 2006. The next brood to emerge is Brood XIII -- the Northern Illinois Brood. After a seventeen-year hiatus, this brood is scheduled to emerge in 2007.

The next thirteen-year brood to emerge will be Brood XIX in 2011 in Maryland and Virginia.

Brood VII is an isolated population in upstate New York and consists only of M. septendecim. It emerged in 2001, and hence its next emergence will be in 2018.

Life Cycle

The nymphs of the periodical cicadas live underground, at depths of 30 cm (one foot) or more, feeding on the juices of plant roots. They stay immobile and go through five development stages before constructing an exit tunnel in the spring of their 13th or 17th year. These exit tunnels have a diameter of about 1-1.5 cm (½ in.)

Emergence holes

The nymphs emerge at an evening when the soil temperature is above 17°C (63 F) and climb to a suitable place on the nearby vegetation to complete their transformation into an adult cicada. They molt one last time and then spend about six days in the leaves waiting for their exoskeleton to harden completely. Just after this final molt, the teneral adults are white, but darken within an hour.

Magicicadas molting

The nymphs emerge in large numbers at about the same time, sometimes more than one million individuals per acre (250/m²). Their mass-emergence is a survival trait called "predator satiation": for the first week after emergence, the periodic cicadas are an easy prey for reptiles, birds, squirrels, cats, and other small and large mammals. The cicadas' survival strategy is simply to overwhelm predators by their sheer numbers, ensuring the survival of most of the individuals and thus of the species.

Adult periodical cicadas live only for a few weeksby mid-July, they'll all be gone. Their short life has one sole purpose: reproduction. The males "sing" a mating song; like other cicadas, they produce loud sounds using their tymbal. The sounds of a "chorus"a group of malescan be deafening and reach 100 dB.

After mating, the male weakens and dies. The female lives a little longer in order to lay eggs: it makes between six and 20 V-shaped slits in the bark of young twigs and deposits up to 600 eggs there. Shortly afterwards, the female also dies. After about six to ten weeks, the eggs hatch and the newborn nymphs drop to the ground, where they burrow and begin another 13 or 17-year cycle.

Magicicadas egg slits (circled in red)

Issue #52

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Silver Dollar

The Silver Dollar (Metynnis argenteus, Ahl 1923) is a tropical fish belonging to the Characidae family which is closely related to the Pirahna. Originating in the Tapajós River basin in South America, this somewhat round-shaped silver fish with slight red-tinged anal fin is mostly found in tanks kept by fish keeping hobbyists. It will grow to a maximum length of 5.5 inches (14.0 centimeters).

Silver Dollar, Metynnis argenteus

The Silver Dollar is a peaceful schooling species that spends most of its time in the mid- to upper-level of the water. Its maximum lifespan is more than 10 years. An egg-layer, the adult fish will spawn around 2,000 eggs. This breeding occurs in soft, warm water in low light.

Silver Dollars natively live in a tropical climate in the sides of weedy rivers. They prefer water with a 5.0-7.0 pH, a water hardness of up to 15.0 dGH, and an ideal temperature range of 75-82 °F (24-28 °C). Their diet is almost exclusively vegetarian and in captivity they will often eat all the plants in a tank. They will also eat worms and small insects.

Conservation status: Unknown

Issue #53

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Vampire Squid

The vampire squid (Vampyroteuthis infernalis), lit. "vampire squid from hell", is a small, deep-sea cirrate (finned) cephalopod found throughout the temperate and tropical oceans of the world. Unique retractile sensory filaments justify the vampire squid's placement in its own order of Vampyromorphida (formerly Vampyromorpha), sharing similarities with both squid and octopuses. As a phylogenetic relic it is the only surviving member of its order, first described and mistakenly identified as an octopus in 1903 by German teuthologist Carl Chun.

A Vampire Squid, Vampyroteuthis infernalis, drawn by Carl Chun, 1903.

Physical description

At a maximum 30 cm (1 foot) in total length, the vampire squid is of no threat to humans. Its 15 cm (6 inch) gelatinous body appears velvety jet-black, red, purple or brown, depending on location and lighting conditions. A webbing of skin connects its eight arms, each lined with rows of fleshy spines or cirri. Only the distal half (farthest from the body) of the arms have suckers. Its limpid, globular eyeswhich appear red or blue, also depending on lightingare proportionately the largest in the animal kingdom at 2.5 cm (1 inch) in diameter.

Mature adults have a pair of ear-like fins projecting from the lateral sides of the mantle. These fins serve as the adult's primary means of propulsion: vampire squid are said to "fly" through the water by way of flapping their fins. Their powerful beak-like jaws are as white as ivory. Within the webbing are two pouches wherein the tactile velar filaments are concealed. The filaments are analogous to a true squid's tentacles, extending well past the arms.

The vampire squid is covered entirely in light-producing organs called photophores. The animal has great control over the organs, capable of producing disorienting flashes of light for fractions of a second to several minutes in duration. The intensity and size of the photophores can also be modulated. Appearing as small white discs, the photophores are larger and more complex at the tips of the arms and at the base of the two fins, but are absent from the underside of the caped arms.

The chromatophores (pigment organs) common to most cephalopods are poorly developed in vampire squid. While this means the animal is not capable of changing their skin colour in the dramatic fashion of shallow-dwelling cephalopods, such trickery is not needed at the pitch black depths in which it lives.

Habitat and adaptations

The vampire squid is an extreme example of a deep-sea cephalopod, thought to reside at aphotic (lightless) depths from 600-900 metres (2,000-3,000 feet) or more. Within this region of the world's oceans is a discrete habitat known as the oxygen minimum zone (OMZ). Within the OMZ oxygen saturation is too low to support aerobic metabolism in most higher organisms. Nonetheless, the vampire squid is able to live and breathe normally in the OMZ at oxygen saturations as low as 3%; a feat no other cephalopodand few other animalscan claim.

In order to cope with life in the suffocating depths, vampire squid have developed several radical adaptations. Of all deep-sea cephalopods, their mass-specific metabolic rate is the lowest. Their blue blood's hemocyanin binds and transports oxygen most efficiently, aided by gills with especially large surface area. The animals have weak musculature but maintain agility and buoyancy with little effort thanks to sophisticated statocysts (balancing organs akin to a human's inner ear) and ammonium-rich gelatinous tissues closely matching the density of the surrounding seawater.

At the shallower end of the vampire squid's vertical range, the view from below is like the sky at twilight: The highly sensitive eyes of deepwater denizens are able to distinguish the silhouettes of other animals moving overhead. To combat this, the vampire squid generates its own bluish light (bioluminescence) in a strategy called counterillumination: The light diffuses the animal's silhouette, effectively "cloaking" its presence from the watchful eyes below. Its own large eyes detect even the faintest of gleams. A pair of photoreceptors are located atop its head, perhaps alerting the animal to movements above.

Like other deep-sea cephalopods, vampire squid lack ink sacs. If threatened, instead of ink, a sticky cloud of bioluminescent mucus containing innumerable orbs of blue light is ejected from the arm tips. This luminous barrage, which may last nearly 10 minutes, is presumably meant to daze would-be predators and allow the vampire squid to disappear into the blackness without the need to swim far. The display is made only if the animal is very agitated; regenerating the mucus is costly.

Issue #54

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Vampire Squid - Cont'd

Development

Few specifics are known regarding the ontogeny of the vampire squid. Their development progresses through three morphologic forms: the very young animals have a single pair of fins, an intermediate form has two pairs, and the mature form again has one. As the animals grow and their surface area to volume ratio drops, the fins are resized and repositioned in order to maximize gait efficiency. Whereas the young propel themselves primarily by jet propulsion, mature adults find flapping their fins to be the most efficient means. This unique ontogeny caused confusion in the past, with the varying forms identified as several species in distinct families.

If hypotheses may be drawn from knowledge of other deep-sea cephalopods, the vampire squid likely reproduces slowly by way of a small number of large eggs. Growth is slow as nutrients are not abundant at depths frequented by the animals. The vastness of their habitat and its sparse population make procreative encounters a fortuitous event. The female may store a male's hydraulically implanted spermatophore (a sort of tapered, cylindrical satchel of sperm) for long periods before she is ready to fertilize her eggs. Once she does, she may need to brood over them for up to 400 days before they hatch. The female will not eat towards this culmination and dies shortly thereafter.

Hatchlings are c. 8 mm in length and are well-developed miniatures of the adults, with some differences. Their arms lack webbing, their eyes are smaller and their velar filaments are not fully formed. The hatchlings are transparent and survive on a generous internal yolk for an unknown period before they begin to actively feed. The smaller animals frequent much deeper waters, perhaps feeding on marine snow (falling organic detritus).

Behaviour

What behavioural data known has been gleaned from ephemeral encounters with ROVs; animals are often damaged during capture and survive for no more than about two months in aquaria. An artificial environment makes reliable observation of non-defensive behaviour difficult.

With their long velar filaments deployed, vampire squid have been observed drifting along in the deep, black ocean currents. If the filaments contact an entity, or if vibrations impinge upon them, the animals investigate with rapid acrobatic movements. They are capable of swimming at speeds equivalent to two body lengths per second, with an acceleration time of five seconds. However, their weak muscles limit stamina considerably.

Unlike their deep-sea relatives, cephalopods living in more hospitable climes can afford to expend energy in protracted flight. Vampire squid must use innovative predator avoidance tactics in order to conserve energy. Their aforementioned bioluminescent "fireworks" are combined with the writhing of glowing arms, erratic movements and escape trajectories, making it difficult for a predator to home in.

In a threat response called "pumpkin posture," the vampire squid inverts its caped arms back over the body, presenting an ostensibly larger form covered in unappetizing spines. The underside of the cape is heavily pigmented, masking most of the body's photophores. The glowing arm tips are clustered together far above the animal's head, diverting attack away from critical areas. If a predator were to bite off an arm tip, the vampire squid can regenerate it.

Copepods, prawns and cnidarians have all been reported as prey of vampire squid. Little else is known regarding their feeding habits, but considering their environment, a fussy palate is unlikely. Vampire squid have been found among the stomach contents of large deepwater fish, deep diving whales and pinnipeds such as sea lions.

Fins look like ears (top) on the "vampire squid from hell." For defence, jagged arms fold back like a skirt.

A live Vampire Squid recently collected from the deep-sea (around 700 meters) off southern California (Pt. Conception) using a modified opening-closing tucker trawl with a thermally-insulated cod-end. The animal shows some evidence of skin damage. The lobed fins characteristic of this species are clearly visible. Note also the "velar filaments", which are modified dorsolateral arms, and the photophores. This photograph, taken on board a ship in a small aquarium, appears on the cover of the Journal of Experimental Biology 201(16), 1998.

Issue #54

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Great Auk

At 75 centimetres or 30 inches, the flightless Great Auk (Pinguinus impennis) was the largest of the auks. It was hunted for food and down for mattresses from at least the 8th century. It is classified as the only species in the genus Pinguinus.

Great Auk, Pinguinus impennis

The Great Auk was once to be found in great numbers on islands off eastern Canada, Greenland, Iceland, Norway, Ireland and Britain, but it was eventually hunted to extinction. The last pair was killed July 3, 1844 on the island of Eldey off Iceland, though a later sighting was claimed of a live individual in 1852 off the Newfoundland Banks in Canada.

They were excellent swimmers, using their wings to swim underwater. Unlike other auks, however, the Great Auk could not fly, which is what made it so vulnerable to humans. The Great Auk laid only one egg each year.

One theory connects the Great Auk with the origin of the word penguin, which may have come from the Welsh phrase pen gwyn, meaning "white head", referring originally to the Great Auk. (Although the head of the Great Auk is not in fact white, there is a white patch behind the beak.) Later, when explorers discovered apparently similar birds in the southern hemisphere, what we now call penguins, the term was supposedly transferred to them. An alternative theory, suggested by John Latham in 1785, claims that the word penguin comes from the Latin pinguis meaning "fat", referring to the plump appearance of the bird.

Conservation status: Extinct (1844)

Issue #55

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American Cocker Spaniel

The American Cocker Spaniel evolved in the United States from spaniels imported from Great Britain. The name cocker comes from the fact that the breed originally hunted woodcock. In the United States the breed is registered under the name "Cocker Spaniel", as is the English Cocker Spaniel in the UK, which can cause confusion between these two breeds. By the 1930s the American variety had become so different from its English ancestors that it was given separate breed status. Originally a gun dog, the Cocker now fulfills the position of family pet or show dog most often and is rarely seen hunting. He is a faithful and responsible children's companion. Cockers have been a highly popular American breed since the 1940s, occupying the top position in number of American Kennel Club registrations in many years.

American Cocker Spaniel

Appearance

American Cockers weigh 24 to 28 pounds (11 to 12.75 kg) and stand 15 inches (38 cm) maximum height. They come in three major colour varieties: black, ASCOB (Any Solid Color Other than Black) and particolor. The other solid colours are chocolate, red, buff, cream, and sable. The domed head, large dark expressive eyes, short deep muzzle, and abrupt stop are characteristic breed points. The coat is flowing, long, silky and abundant. The long, luxuriantly feathered ears are a striking breed feature.

Temperament

Their temperament is typically happy, trusting, and intelligent. However, their popularity also led to considerable bad breeding in an attempt to keep up with the demand, and some lines contain dogs who tend to be high strung and snappish. As with all puppies, owners are advised to choose their breeder carefully.

Health

Cocker Spaniels are susceptible to a variety of maladies, particularly infections, affecting their ears and, in some cases, their eyes. As a result, they may require more medical attention than some other breeds.

History

The name cocker comes from the fact that the breed originally hunted woodcock. In the United States the breed is registered under the name "Cocker Spaniel", as is the English Cocker Spaniel in the UK, which can cause confusion between these two breeds. By the 1930s the American variety had become so different from its English ancestors that it was given separate breed status. Originally a gun dog, the Cocker now fulfills the position of family pet or show dog most often and is rarely seen hunting. He is a faithful and responsible children's companion. Cockers have been a highly popular American breed since the 1940s, occupying the top position in number of American Kennel Club registrations in many years.

Alternative name: Cocker Spaniel
Country of origin: United States

Issue #56

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Orangutan

Orangutans (also spelled orang utan, orang-utan, sometimes incorrectly orangutang) are two species of great apes with long arms and reddish, sometimes brown, hair native to Malaysia and Indonesia. The word orangutan is derived from the Malay orang hutan meaning man of the forest. They are the only extant species in the genus Pongo and the subfamily Ponginae, although that subfamily also includes the extinct Gigantopithecus and Sivapithecus genera.

An orangutan, genus Pongo

Orangutans are the most arboreal of the great apes, spending nearly all of their time in the trees. They are only found in rainforests on the islands of Borneo and Sumatra. These two small isolated populations were classified as subspecies until recently, when they were elevated to full specific level (Pongo pygmaeus on Borneo, and P. abelii on Sumatra). Furthermore, primatologists now recognise three subspecies of the Bornean orangutan: P. p. pygmaeus in northwest Borneo, P. p. morio in northeast and east Borneo, and P. p. wurmbii in southwest Borneo.

Orangutans are highly endangered in the wild. Orangutan habitat destruction due to logging, mining and forest fires has been increasing rapidly in the last decade. Much of this activity is illegal, occurring in national parks that are officially off limits to loggers, miners and plantation development. There is also a major problem with the illegal trapping of baby orangutans for sale into the pet trade; the trappers usually kill the mother to steal the baby.

Like the other great apes, orangutans are remarkably intelligent. In the mid-1990s, one population of orangutans was found to use feeding tools regularly. Evidence of this had been earlier discovered among chimpanzees by Jane Goodall in the 1960s. A 2003 paper in the journal Science described the evidence for distinct orangutan cultures (see link). Orangutans are generally among the least aggressive among the apes, being friendly animals. Particularly notable is that wild orangutans are known to visit human-run facilities for orphaned young orangutans released from illegal captivity, interacting with the orphans and probably helping them adapt in their return to living in the wild.

Major conservation centres in Borneo include those at Semenggok in Sarawak, and Sepilok near Sandakan in Sabah.

Conservation status: Endangered

Issue #57

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Eurasian Eagle Owl

The Eurasian Eagle Owl (Bubo bubo) is a species of horned owl resident in much of Europe and Asia.

Eurasian Eagle Owl, Bubo bubo

The horned owls are a part of the larger grouping of owls known as the typical owls, Strigidae, which contains most species of owl. The other grouping is the barn owls, Tytonidae.

The Eagle Owl is a very large and powerful bird, larger than a Buzzard. It is 59-73 cm long with a 138-170 cm wingspan. It is capable of killing large prey items such as hares, crows and gulls.

It is largely nocturnal, and is found in mountains and forests with cliffs and rocky areas. It usually nests on cliff ledges.

The size, ear tufts and orange eyes make this a very distinctive species. It has a strong direct flight.

The Eagle Owl's scientific name comes from its deep booming call.

Eagle Owl at Combe Martin Wildlife and Dinosaur Park, North Devon, England.

Issue #58

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Galápagos tortoise

The Galápagos tortoise (or giant Galápagos tortoise), Geochelone nigra, is the largest living tortoise. It can weigh over 225 kg (500 pounds) and measure 1.8 m (6 feet) from head to tail. It is a very slow-moving animal, moving only 0.25 km/h (0.16 miles per hour). It is a herbivore, eating grasses, plant leaves, cactus and fruits.

Galápagos tortoise, Geochelone nigra

The Galápagos tortoise has a very large shell (or carapace) made of bone. The shape of the carapace and other morphological features are indicative of the terrain the animal inhabits. Highland areas with lush vegetation near the ground are normally home to tortoises with domed shells; these animals have restricted upward head movement due to shorter necks, and tend to have shorter limbs as well (see photo). Coastal regions with less vegetation at ground level are inhabited by tortoises with saddle-back shells; their extended necks and limbs help them to reach food higher off the ground. Shells can also be of intermediate type, with characteristics between domed and saddle-back types.

The Galápagos tortoise is found on the Galápagos Islands just west of Ecuador in South America. Because of the 250,000 tortoises that inhabited the island, Spanish explorers named the islands Galápagos for the giant tortoises. Today only 15,000 are left.

One of the oldest living specimens is a giant Galápagos tortoise named Harriet in the Australia Zoo at Beerwah, Queensland, Australia. Its estimated date of birth is 1830.

Conservation status: Vulnerable

Issue #59

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Caecilian

The Caecilians are an order (Gymnophiona or Apoda) of amphibians which resemble worms or snakes. They mostly live hidden in the ground which makes them the least explored order of amphibians, and widely unknown.

Caecilian, order Gymnophiona or Apoda

Anatomy

Caecilians' feet have degenerated, making the smaller species resemble worms, while the larger species with lengths up to 1.5 m resemble snakes. The tail is also very short, so the cloaca is near the end of the body. Their skin is smooth and usually dark-matt, but many species also have colorful skins. Inside the skin are calcite scales, which suggests that they are related with the fossil Stegocephalia. However the scales are now believed to be a secondary development, and not directly inherited from Stegocephalia. Due to their underground life the eyes are small and covered by skin for protection, which have led to the misconception that they are blind. However due to the skin cover their visual sense is limited to simple dark-light perception. All Caecilians share two tentacles at their head, which are probably used for the olfactory sense additional to the normal nose.

Except one lungless species - Typhlonectes eiselti, only known from one specimen collected somewhere in South America - all Caecilians have lungs, but also use the skin or the mouth for oxygen absorption. Often the left lung is much smaller than the right one, an adaptation to the body shape also found in snakes.

Distribution

Caecilians are found in most of the tropic areas of South-East Asia, Africa and South America, except the dry areas and the high mountains. In South America their distribution extends well into the temperate north of Argentina. For central Africa no systematic search has been done yet, but it is likely Caecilians are found all over the tropical rainforest there.

Reproduction

Caecilians are the only order of amphibians which only use internal insemination. The male Caecilians have a penis-like organ, the phallodeum, which is inserted into the cloaca of the female for 2 to 3 hours. About 25% of the species are oviparous; the eggs are guarded by the female. For some species the young Caecilians are already metamorphed when they hatch, other hatch as larvae. The larvae aren't fully aquatic, but spend the daytime in the soil near the water.

75% of the species are viviparous, that means they give birth to already developed offspring. The fetus is fed inside the female with special cells of the oviduct, which are eaten by the fetus with special scraping teeth.

Origin of the name

The name Caecilian derives from the Latin word caecus = blind, referring to the small or sometimes non-existing eyes. The name dates back to the taxonomic name of the first species described by Carolus Linnaeus, which he gave the name Caecilia tentaculata. The taxonomic name of the order derives from the Greek words gymnos = naked and ophio = snake, as the Caecilians were originally thought to be related with snakes.

Taxonomy

Taxonomically the Caecilians are divided into 5 families. The species numbers have to be taken with care, as many of the species are described after only one specimen. Probably not all species have been described yet, however some of the described different species might turn out to be normal variations inside one species.

- Beaked Caecilians (Rhinatrematidae) - 2 genera, 9 species
- Fish Caecilians (Ichthyophiidae) - 2 genera, 39 species
- Indian Caecilians (Uraeotyphlidae) - 1 genus, 5 species
- Tropical Caecilians (Scolecomorphidae) - 2 genera, 6 species
- Common Caecilians (Caeciliidae) - 26 genera, 107 species

Miscellany

Large Caecilians dubbed "ingots" plagued the French occupation of Indochina in the years before the Vietnam war. The creatures were reported to borrow large holes and disrupt troop movement.

Issue #60

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Flea

Flea is the common name for any of the small wingless insects of the order Siphonaptera. Fleas are external parasites, living off the blood of mammals and birds.

Scanning Electron Micrograph of a Flea, order Siphonaptera

Some well known flea species include:

- Cat Flea (Ctenocephalides felis),
- Dog Flea (Ctenocephalides canis),
- Northern Rat Flea (Nosopsyllus fasciatus),
- Oriental Rat Flea (Xenopsylla cheopis).

In most cases fleas are just a nuisance to their hosts, but some people and some animals suffer allergic reactions to flea saliva resulting in rashes. Flea bites generally result in the formation of a slightly-raised swollen itching spot with a single puncture point at the center.

However, fleas can transmit disease. One devastating example of this was the bubonic plague, transmitted between rodents and humans. Murine typhus (endemic typhus) fever, and in some cases tapeworms can also be transmitted by fleas.

Life Cycle

Fleas pass through a complete life cycle consisting of egg, larva, pupa and adult. Completion of the life cycle from egg to adult varies from two weeks to eight months depending on the temperature, humidity, food, and species. Normally after a blood meal, the female flea lays about 15 to 20 eggs per day up to 600 in its lifetime usually on the host (dogs, cats, rats, rabbits, mice, squirrels, chipmunks, raccoons, opossums, foxes, chickens, humans, etc.). Eggs loosely laid in the hair coat drop out almost anywhere, especially where the host rests, sleeps or nests (rugs, carpets, upholstered furniture, cat or dog boxes, kennels, sand boxes, etc.).

Greyscale picture of Robert Hooke's drawing of a flea in his Micrographia.

Eggs hatch between two days to two weeks into larvae found indoors in floor cracks, crevices, along baseboards, under rug edges and in furniture or beds. Outdoor development occurs in sandy gravel soils (moist sand boxes, dirt crawlspace under the house, under shrubs, etc.) where the host may rest or sleep. Sand and gravel are very suitable for larval development which is the reason fleas are erroneously called "sand fleas."

Larvae are blind, avoid light, pass through three larval instars and take a week to several months to develop. Their food consists of digested blood from adult flea feces, dead skin, hair, feathers, and other organic debris; larvae do not suck blood. Pupae mature to adulthood within a silken cocoon woven by the larva to which pet hair, carpet fiber, dust, grass cuttings, and other debris adheres. In about five to fourteen days, adult fleas emerge or may remain resting in the cocoon until the detection of vibration (pet and people movement), pressure (host animal lying down on them), heat, noise, or carbon dioxide (meaning a potential blood source is near). Most fleas overwinter in the larval or pupal stage with survival and growth best during warm, moist winters and spring.

Flea bites can be treated with Calamine Lotion.

Families

Tungidae - Sticktight and Chigoe fleas
Pulicidae - Common fleas
Coptopsyllidae
Vermipsyllidae - Carnivore fleas
Rhopalopsyllidae - Marsupial fleas
Hypsophthalmidae
Stephanocircidae
Pygiopsyllidae
Hystrichopsyllidae - Rat and mouse fleas
Leptopsyllidae - Bird and rabbit fleas
Ischnopsyllidae - Bat fleas
Ceratophyllidae
Amphipsyllidae
Malacopsyllidae
Dolichopsyllidae - Rodent fleas
Ctenopsyllidae

Issue #61

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Zebra Danio

The Zebra Danio or Zebrafish (Brachydanio rerio or Danio rerio) is a tropical fish belonging to the minnow family (Cyprinidae). Originating in Eastern India, it grows to about 2 inches (6 cm) and lives for around 5 years. There are long-finned and other color forms of this danio.

Zebra Danio, Danio rerio

Like other danios it is omnivorous and a peaceful fish that gets along well with other fish in community tanks. A schooling fish, it prefers to be in groups of 6 or more. Zebra Danios prefer water with a 6.08.0 pH, a water hardness of up to 5.019.0 dGH, and a temperature range of 6474°F (1824°C).

Males have gold stripes between the blue stripes and females have silver stripes instead of gold. An egg-scatterer, danios produce around 100 eggs in a single spawning.

Zebra Danios serve as a common and useful model organism for studies of vertebrate development, because it reproduces very easily, passing from the egg to the larvae stage in less than three days. For genetic research groups, the Zebrafish is an excellent test subject and has already replaced rats and mice in many labs. Zebra danio is one of the few species of fish to have been flown into space. If researchers modify its genotype at the egg stage, they can see results on its organs barely three days later aided by the transparency of the embryos. A common reverse genetics technique is to knock down gene expression or modify splicing in Zebrafish using Morpholino antisense.

Because of this interest it has been one of the first organisms to have its genome sequenced. The results of genetic engineering in these fishes have been used to produce the Glofish, an aquarium pet with fluorescent pigments.

Zebra Danios are susceptible to Oodinium, or Velvet disease.

Zebra Danios are omnivorous. Live/frozen flaked foods are suitable, especially brine shrimp. When conditioning zebras for breeding, it's advisable to feed them plenty of fresh foods.

Zebrafishes are used as a model organism for genetic analysis of genes. These fishes have the advantage of fast and easy growth in the laboratory. See the external links for more information.

Issue #62

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Sea anemone

Named after a terrestrial flower, the anemone, the sea anemone is a group of water-dwelling, filter feeding animals of the order Actinaria. As a cnidarian, it is closely related to coral and jellyfish. The anemone is a (usually) solitary polyp with stinging cells (cnidocytes) in its tentacles. These stinging cells serve to paralyze and capture prey, which is then moved by the tentacles to the mouth for digestion inside a central cavity.

Giant Green Sea Anemone, order Actinaria, Southern California

Other close relations to the sea anemone are the solitary, tube-dwelling anemones and the hydras.

The sea anemone has a foot which in most species attaches itself to rocks or anchors in the sand. Some species attach to kelp and others are free-swimming. Although not plants and therefore incapable of photosynthesis themselves, many sea anemones form an important symbiosis with certain single-celled green algae species which reside in the animals' gastrodermal cells. These algae may be either zooxanthellae, zoochlorellae or both. The sea anemone benefits from the products of the algae's photosynthesis, namely oxygen and food in the form of glycerol, glucose and alanine; the algae in turn are assured a reliable exposure to sunlight, which the anemones actively maintain. The preponderance of species inhabit tropical reefs, although there are species adapted to relatively cold waters, intertidal reefs, and sand/kelp environments.

Some sea anemones form symbiotic relationships with crabs and anemone fish, also known as clownfish. In the former situation, anemones will either attach or be attached to the shell of a hermit crab (by the crab's own volition), providing additional protection for the crab and allowing the anemone to eat scraps when the crab feeds. A similar relationship can be formed between a sea anemone and a clownfish. The clownfish presses itself into the anemone, living comfortably within the stinging tentacles: This is possible because of a protective slime that covers the clownfish. The clownfish benefits from this symbiotic relationship because it is protected by the anemone. The anemone benefits because the anemone gets food scraps from the clownfish.

Common Clownfish (Amphiprion ocellaris) in their Magnificent Sea Anemone (Heteractis magnifica) home.

Sea anemones at the aquarium in Bristol Zoo, Bristol, England.

Starfish and anemones in a cold water rocky community.

Issue #63

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Dimetrodon

Dimetrodon was a predatory synapsid (mammal-like "reptile") genus that flourished during the Permian period, living between 280 and 260 million years ago. It is more closely related to mammals than to true reptiles (Sauropsida) like dinosaurs, lizards and birds. Dimetrodon was not a dinosaur, despite being popularly grouped with them; rather, it is classified as a pelycosaur.

Fossil skeleton of Dimetrodon grandis at the National Museum of Natural History, Washington, DC

Dimetrodon was a dominant carnivore, the largest of its day. It grew to up to 3 meters in length. Dimetrodon means "two-measures teeth"; it is so named because it had a large skull with two different types of teeth (shearing teeth and sharp canine teeth), as opposed to the dinosaurs. It walked on four side-sprawling legs and had a large tail.

Dimetrodon's most distinctive characteristic is the spectacular sail on its back. The sail was probably used to regulate body temperature; the surface area would allow it to warm up or cool off more efficiently. It may also have been used in mating rituals and to ward off other predators. The sail was supported by neural spines, each one sprouting from an individual vertebra.

Dimetrodon was discovered in Texas by Edward Drinker Cope.

Conservation status: Fossil

Issue #64

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Bengal cat

The Bengal cat is a domestic cat breed with 'wild' characteristics and coloration, but a domestic temperament. They are medium sized cats - a male may weigh as much as 15 lb (7 kg), and a female commonly weighs 8 to 10 lb (4 to 5 kg). The closer the cat is to their Asian Leopard ancestors, the larger it is likely to be.

A Bengal kitten, aged 13 weeks

Bengal cats are actually a hybrid between Asian Leopard Cats and domestic felines - mainly Egyptian Maus, American Shorthair, Abyssinian, Ocicat, and domestic shorthaired cats, as well as later generation Bengal males. Developed by Jean Mill of California in the 1970's, Bengal cats are labelled with an 'F' number to indicate how many generations they are removed from their wild ancestors. Kittens from an Asian Leopard Cat (crossed with a Bengal cat or domestic cat) would be called F1 Bengal cats, their offspring would then be called F2 Bengals and so on. Bengal cats from F1 to F3 are not allowed to be shown, due to their still semi-wild nature, although many F3 Bengal cats are very friendly. Asian Leopard cats or F1 and F2 Bengal cats may not be easily house-trained and need knowledgeable owners. They are often difficult to breed (F1 and F2 males are always infertile and F3 males are almost always infertile), with smaller litters. Consequently, when they are occasionally sold, they are much more expensive than later generation Bengal cats. A special breeders license is needed to care for F1 bengal cats or for their Asian leopard cat parents.

Bengal cats are either spotted or have marbled patterns on their coats. The following colors and patterns are recognized: Brown Spotted Tabby, Brown Marbled Tabby, Seal Sepia Spotted Tabby, Seal Sepia Marbled Tabby, Seal Mink Spotted Tabby, Seal Mink Marbled Tabby, Seal Spotted Lynx Point and Seal Marbled Lynx Point only.

Bengal cats can take a great deal of interest in running water and often don't mind getting wet. Most Bengal owners have stories about their cat's affection for running water or even jumping in a sink or tub. Additionally, Bengal cats are very intelligent and curious, and so are particularly interactive with their human housemates, wanting to be in the middle of whatever the human is engaged in, and often following the human around the house as household chores are performed. Bengals tend to vocalize to communicate with their humans, and are quite capable of jeoulousy and spitefulness if they feel that another feline is getting more attention. The other side of this coin is that they are also extremely affectionate towards and playful with their humans. Excellent hearing and highly developed instincts make Bengal cats excellent "watch dogs." Manx is yet another cat breed that share many of these similar traits with the Bengal cat.

A litter of Bengal kittens

Bengal kittens, at two weeks

An eight-month-old Bengal

Country of origin: United States

Issue #65

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Bumblebee Bat

The Bumblebee Bat or perhaps more correctly Kitti's Hog-nosed Bat, (Craseonycteris thonglongyai) is the world's smallest species of bat at 29-33 mm in length and a weight of 2 grams (about as much as a dime). It is the only known species in its genus and is found in a tiny region of western Thailand, at Sai Yoke in the Kanchanburi province.

A Bumblebee Bat, Craseonycteris thonglongyai, hanging on a rocky outcropping.

The bat is named a Bumblebee Bat because it is about the size of a bumblebee. It competes with the Etruscan Pygmy Shrew for the title of world's smallest mammal. At issue is whether skull size or mass defines "smallest"; the shrew is lighter but the bat's skull, shown below, is smaller at 11 mm.

The skull of the Bumblebee Bat, at 11 mm, is smaller than any other mammal.

The Bumblebee Bat has reddish-brown upperparts, although the species seems to occur as another colour phase that has greyer upperparts. The underside is always a paler version of the top. The ears are relatively large and extend beyond the rather pig-like snout when lying forward.

They are most active at dusk when they fly around the tops of bamboo clumps and teak trees to feed on insects. The wings are quite long and broad with pointed tips and dark membrane. They seem to be shaped for hovering flight and indeed gut contents of specimens do include spiders as well as other small insects that have been gleaned off foliage. Insects are also caught in straight flight.

Bumblebee Bats roost in the hot upper chambers of caves in limestone hills, just about as far away from the entrance so that the small colony up to 15 individuals can fit without the bats being too close to each other.

The bats are small both in size and in number. The species was unknown prior to 1974. Their already restricted habitat has been highly affected by deforestation and unsustainable levels of teak logging. In 1982, the Royal Forest Department of the Thailand Government only found 160 of them living in 3 caves, despite extensive surveys. Bumblebee bats are now considered one of the twelve most endangered species on the planet.

Issue #66

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