Dolichotis patagona

Also known as the Patagonian cavy, this large rodent is one of the world’s few monogamous mammals. Its head and body length is up to 75 cm, and it weighs between nine and 16 kg.

Home Range

Central and southern Argentina

Habitat

Arid grasslands

Diet

Grasses and any other vegetation

Reproduction

Maras may produce three or four litters (usually two young) per year.

Social Structure

Maras are monogamous (they mate for life).

Fun Fact

Patagonian maras are in the Family Caviidae, which includes cavies and guinea pigs. These South American rodents have stocky bodies, three sharp-clawed digits on the hind feet, and four digits of the forefeet. Maras resemble long-legged rabbits. — nationalzoo.si.edu

Any of several species of toothless insectivorous mammals, covered with horny overlapping plates, that live in Asia and Africa.

It has short, powerful forelegs with which it climbs trees and tears open the nests of tree ants, on which it feeds. Length: to 175cm (70in). Family Manidae; genus Manis. — www.encyclopedia.com

Conidae

“For centuries members of the Conidae family have been collected for their unique and intricately designed shells. Only during the last few decades have cone shells become an exciting area for scientific research.”

“Cone shells are marine snails and are found in reef environments throughout the world. They prey upon other marine organisms, immobilizing them with unique venom. There have been 30 recorded cases of human envenomation by fish-eating cone shells, in some cases fatal. Upon investigation it was found that toxins in cone shell venom possess pharmacological qualities that make them valuable tools in medical research.

In the dynamic marine environment in which cone shells reside, it has been necessary for these gastropods to develop an effective mechanism for immobilizing their otherwise speedy prey.The solution to the snail’s lack of physical agility has been the development of a highly potent concoction of neuronal toxins, which it uses to paralyze its prey (an especially vital factor for the fish eating species).

Cone shells can be classified according to their prey:

- Piscivorous–fish eaters
- Molluscivorous–mollusk eaters
- Vermivorous–worm eaters

Detection of the Prey

The cone shell detects prey in its environment using a “siphon” which bristles with chemoreceptors. It then extends its proboscis out towards the unfortunate target.

Injection of the venom

The venom is produced in a long tubular duct that is often several times the length of the snail itself and at one end is attached to a muscular bulb which is thought to contract to provide the necessary force of venom injection through the ‘tooth’. Hollow spear-like radular teeth, which are made in the ‘radular sac’ and filled with venom, are transported through the ‘buccal cavity’ to the tip of the proboscis where they are retained by radular muscle.

Upon contact with the prey, the proboscis impales the harpoon like tooth into any exposed tissue and injects the venom through this. The harpoon is attached to the gastropod via a ‘thread’ so that the prey is actually tethered to the snail (although the organism is often paralyzed within one or two seconds, leaving little opportunity to escape). Once the prey is paralyzed, the gastropod retracts the cord by which the prey is attached and engulfs the prey through it’s the radular opening of it’s proboscis and into its distensible stomach where it is digested. The cone shell can reload further teeth from the radular sac for multiple envenomation by retracting the proboscis into the radular sac and grasping another tooth with the radular muscle.

Composition of the Venom

The composition of the venom differs greatly between species and between individual snails within each species, each optimally evolved to paralyze its prey. The active components of the venom are small peptides toxins, typically 12-30 amino acid residues in length and are highly constrained peptides due to their high density of disulfide bonds.

The composition of the venom is different with each injection. The pharmacological activity also changes, the venom containing lethal and paralytic neurotoxic peptides as well as components which elicit specific and varied physiological and behavioral responses when tested in mice, from shaking to depression! The paralysis of the prey by the killer-snail venom permits correct presentation of the prey to the gastropod so that it engulfed and enzymatically digested by the killer snail’s distensible stomach.

The paralytic components of the venom that have been the focus of recent investigation are the alpha-, omega- and mu-conotoxins. All of these conotoxins act by preventing neuronal communication, but each targets a different aspect of the process to achieve this. The alpha-conotoxins target nicotinic ligand gated channels, the mu-conotoxins target the voltage-gated sodium channels and the omega-conotoxins target the voltage-gated calcium channels.”

First aid for Cone shell stings

The venom of these creatures contains a number of neurotoxic peptides that cause weakness and loss of coordination. The victim’s vision, speech and hearing are disturbed. Nausea and general pruritis are some of the less common symptoms. Numbness, local pain and swelling may also occur. In cases of severe envenomation, respiratory muscle paralysis may lead to death. Pressure-immobilization should be used and, if necessary, assisted ventilation. There is no antivenom developed for cone snail stings. Because the wound can be contaminated, tetanus prophylaxis should be performed. — library.thinkquest.org

Found only on the islands of Oahu, Molokai, Maui, and Hawaii, the happy face spider, such as this one guarding its eggs on a leaf in Maui, is known for the unique patterns that decorate its pale abdomen.

Scientists believe Theridion grallator may have developed its distinctive markings to discourage birds from eating it. — photography.nationalgeographic.com

The basking shark (Cetorhinus maximus) is a huge filter feeding shark which grows to be up to about 33 feet (10 m) long. It is the second-largest shark (after the whale shark). The basking shark is also called the sunfish, the bone shark, the elephant shark, the sailfish shark, and the big mouth shark.

GENERAL DESCRIPTION

This huge, bulky, filter-feeder is grayish brown to black to bluish on the upper surface and off-white or darker on its belly. It has a huge mouth which it uses to collect tiny food that floats in the water. A sluggish swimmer with huge gills and dark, bristle-like gill rakers, it filters its food from the water. The snout is short and conical.

SIZE

Female basking sharks are up to 33 feet (10 m) long; males are up to 30 feet (9 m) long. This enormous shark weighs up to 4 tons. It is the second largest fish in the world; the whale shark is the largest.

TEETH

Basking sharks have hundreds of teeth (each having a single cusp, curving backwards) but they are tiny and are of little use.

DIET AND FEEDING HABITS

Basking sharks are filter feeders that sieve small animals from the water. As the basking shark swims with its mouth open, masses of water filled with prey flow through its mouth. The prey includes plankton, baby fish, and fish eggs. After closing its mouth, the shark uses gill rakers that filter the nourishment from the water. Gill rakers are bristly structures (the thousands of bristles are about 4 inches or 10 cm long) in the shark’s mouth that trap the small organisms which the shark then swallows. The water is expelled through the shark’s 5 pairs of gill slits. The shark can process over 1500 gallons (6000 liters) of water each hour.

SOCIAL GROUPS

Basking sharks travel alone, in pairs, or in schools (groups) of up to 100 members.
HABITAT

Basking sharks live in coastal temperate waters. They spend most of their time at the surface, hence their nickname the “sunfish.”

DISTRIBUTION

Basking sharks are found off the coasts of western North America from Baja to southern Alaska, off the east coast of the US and southern Canada, along the Gulf Stream, to the entire coastline of Europe, off the southern coast of Australia, off South Africa, New Zealand, most of southern South America, the Red Sea, and the coastlines of China and Japan.

SWIMMING

Basking sharks are slow swimmers, going no more than 3 mph (5 kph). They swim by moving their entire bodies from side to side (not just their tails, like some other sharks do).

REPRODUCTION

Basking sharks reach sexual maturity at about 2-4 years old. They mate in the summer off the coasts of Iceland and northern Europe. The gestation period is about 3.5 years. They probably reproduce via aplacental viviparity. Females give birth to 1-2 live young. which are about 5.5 feet (1.7 m) long. These are the largest shark pups.

Like all sharks, fertilization of the eggs occurs within the female. The eggs hatch within the female and are nourished by eating unfertilized eggs in the womb. There is no placenta to nourish the babies - they must fend for themselves, even before birth. They swim away from the mother immediately after birth, there is no maternal care-giving.

SHARK ATTACKS

Basking sharks are not aggressive and are generally harmless to people.

MIGRATION

Basking sharks migrate seasonally, eating in cool northern waters, moving south during the winter.

POPULATION COUNT

The number of basking sharks is unknown, but it may be decreasing since the basking shark is hunted for its meat, fins and oil.

BASKING SHARK CLASSIFICATION

Kingdom Animalia (animals)
Phylum Chordata
Subphylum Vertebrata (vertebrates)
Class Chondrichthyes (cartilaginous fish)
Subclass Elasmobranchii (sharks and rays)
Order Lamniformes
Family Cetorhinidae
Genus Cetorhinus
Species maximus — www.enchantedlearning.com

A marine biologist has discovered a startling new crab species that resembles a large strawberry.

The unusual crustacean was found off the coast of southern Taiwan. It has a dramatic bright red shell covered with small white bumps.

Professor Ho Ping-ho from the National Taiwan Ocean University said the crab resembles a species called Neoliomera Pubescens, that lives in the areas around Hawaii, Polynesia and Mauritius.

However it has a clam-shaped shell about 1 inch wide, which makes it distinct.

Crabs are omnivores feeding primarily on algae. There are more than 5,000 known species in the world.

Professor Ho said his team found two female crabs of the new species last June off the coast of Kenting National Park, known for its rich marine life.

The crabs died shortly afterwards, possibly because the water in the area was polluted by a cargo ship that ran aground.

Taiwanese crab specialist Wang Chia-hsiang confirmed Professor Ho’s finding. — www.dailymail.co.uk

It’s not so much eternal life, more a case of instant death. Parasitic beetles that dare to invade the hive of certain stingless bees end up entombed forever in resin. “They’re stopped in their tracks and they dehydrate and shrivel up like a mummy,” says Mark Greco, an entomologist at the Swiss Bee Research Centre in Bern who discovered the practice in a species of Australian stingless bees, Trigona carbonaria, living in the wild.

To further investigate this peculiar defence, Greco’s team planted parasitic small hive beetles, Aethina tumida, near the entrance of laboratory beehives. Guard worker bees instantly attacked the parasites, but the thick-skinned beetles had little trouble warding them off.

Faced with such a resilient foe, a group of workers resorted to coating the beetles in a sticky mix of resin, mud and wax. From computerised tomography (CT) scans of hives flash-frozen at 5-minute intervals, Greco’s team found the mummifications take less than 10 minutes.

The beetles rarely got very far from the entrance before being mummified. The only time Greco saw the beetle invasions succeed was during a hot Australian summer, when temperatures above 40 °C may have stressed the bee colony and prevented the resin from setting.

The behaviour may have evolved out of conventional hive-patching, in which stingless bees use a similar resin to secure loose bits of their hive. “Their instinct is to glue something down if it’s not secure,” Greco says.

Other stingless bees also make mummies out of intruders. Some tropical species even mix in acidic secretions that eat away at the beetle’s hard cuticle. — www.newscientist.com

Tapiridae

Tapirs look something like pigs with trunks, but they are actually related to horses and rhinoceroses. This eclectic lineage is an ancient one—and so is the tapir itself. Scientists believe that these animals have changed little over tens of millions of years.

Tapirs have a short prehensile (gripping) trunk, which is really an extended nose and upper lip. They use this trunk to grab branches and clean them of leaves or to help pluck tasty fruit. Tapirs feed each morning and evening. During these hours they follow tunnel-like paths, worn through the heavy brush by many a tapir footstep, to reach water holes and lush feeding grounds. As they roam and defecate they deposit the seeds they have consumed and promote future plant growth.

Though they appear densely built, tapirs are at home in the water and often submerge to cool off. They are excellent swimmers and can even dive to feed on aquatic plants. They also wallow in mud, perhaps to remove pesky ticks from their thick hides.

New World tapirs generally live in the forests and grasslands of Central and South America. A notable exception is the mountain (or woolly), tapir, which lives high in the Andes Mountains. Woolly tapirs, named for their warm and protective coat, are the smallest of all tapirs.

The world’s biggest tapir is found in the Old World—Southeast Asia. The black-and-white Malay tapir can grow to 800 pounds (363 kilograms). It inhabits the forests and swamps of Malaysia and Sumatra.

All four tapir species are endangered or threatened, largely due to hunting and habitat loss. — animals.nationalgeographic.com

A group of glowing worms has been found dwelling in the deep ocean, some of which release body parts as tiny “bombs” to ward off predators.

Researchers describe the bizarre “Swima worms” in Science journal.

The creatures, which the scientists say could be widespread in the deep sea, indicate the extent of biodiversity yet to be discovered in the oceans.

The team found them whilst exploring the waters just above the sea-bed off the west coast of the US.

Lead author Karen Osborn, from the University of California San Diego, told BBC News that she and her colleagues found the worms accidentally, whilst exploring the deep oceans with remotely operated submersible vehicles.

“We came across them and thought they were very interesting, firstly because of their bioluminescence,” she said.

“When we brought them up and realised they were different from anything that had been described before, we became even more interested.”

Dr Osborn and her colleagues were exploring depths of up to 3,700m when they spotted the creatures.

As they continued to bring more of the worms back to their lab, they realised they had found a group of previously unknown animals.

Each of the seven species found so far is transparent apart its gut, and all of the worms produce colourful bioluminescence.

The researchers are now investigating what chemicals the animals produce to give rise to their striking glow.

The animals are also excellent swimmers - using fans of long bristles that form swimming paddles.

Five of the species release the glowing bombs, which probably serve to distract predators while the worm escapes. The team has named the first of these species Swima bombiviridis.

“They usually have about eight of the bombs, and they drop one or two at a time,” explained Dr Osborn.

Because of the tiny size of the bombs - approximately 1-2mm in diameter - and the bright lights used by the submersible vehicles, the team was unable to capture this bombing on film in the deep ocean.

“So we bring the animals up to study them,” Dr Osborn said. “If you transfer the animal into a small tank, and harass it a little bit with forceps - kind of bump it anywhere on the body - it will release one of these bombs.

“As soon as [the bomb] is released it starts glowing green and the animal swims away.”

Greg Rouse, another member of the research team, explained that a common ancestor of the species had gills that appeared to be “in exactly the same places as the bombs”, from which the bombs could have evolved.

“The gills (of their relatives) can fall off very easily so there’s a similarity of being detachable, but for some reason the gills have transformed to become these glowing little detachable spheres.”

Dr Osborn concluded: “This group of really fantastic animals emphasises just how much we have to learn about deep sea organisms and deep sea biodiversity.” — news.bbc.co.uk

Dobsonflies are species of medium- to large-sized insects in the order Neuroptera, family Corydalidae.

The life cycle of dobsonflies is characterized by a complete metamorphosis, with four developmental stages: egg, larva, pupa, and adult. Adult dobsonflies are usually found near freshwater, especially streams, either resting on vegetation or engaged in an awkward, fluttering flight. Sometimes adult dobsonflies can be abundant at night around lights, even far from water. The immature stages of dobsonflies are aquatic and are usually found beneath stones or other debris in swiftly flowing streams.

Dobsonflies have rather soft bodies. The adults of North American species generally have body lengths of 0.75-1.5 in (2-4 cm) and wing spans of 2 in (5 cm) or greater. These insects have four wings with distinctive, many-veined membranes. The wings are held tent-like over the back when the insect is at rest. Dobsonflies have piercing mouthparts. Male dobsonflies have large mandibles about three times longer than the head and projecting forward. Female dobsonflies have much smaller mandibles. Adult dobsonflies are active at night and are not believed to feed, so the function of the exaggerated mandibles of the male insects are unknown. Dobsonflies lay their eggs on vegetation near water, and the larvae enter the water soon after hatching.

Larval dobsonflies are sometimes known as hellgrammites and are predators of other aquatic invertebrates. Larval dobsonflies are quite large, often longer than 3 in (8 cm) or more, with distinctive, tracheal gills projecting from the segments of their large abdomen. Larval dobsonflies are sometimes used as bait for trout fishing.

Various species of dobsonflies occur in North America. The species Corydalus cornutus is common but not abundant in eastern parts of the continent, while the genus Dysmicohermes is widespread in western regions. — science.jrank.org