Squid

True Wild Life | Squid | The squid is a marine cephalopod similar to the octopus. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms and two tentacles arranged in pairs. Some species of squid are known to have 10 arms.

There are around 300 different species of squid found in the oceans worldwide, with squid being one of the few animals that inhabits the freezing waters of the Antarctic, where they mainly feed on krill and plankton although larger species of squid have also been known to hunt larger prey like fish.

Most species of squid average at about 20 cm in length when they are fully grown although some species will commonly grow to 60 cm long. The Colossal squid that lives in the deep waters of the Pacific Ocean has been known to grow to 14 metres long!

Squid are an excellent and therefore common food source for a variety a different animal species in the water but also those predators on land. Squid predators include sharks, penguins, seals and humans. Generally squid will only get to a few years old in the wild before being eaten. Some of the bigger species of squid however, have been known to reach ages of 15 years old.

Snail

True Wild Life | Snail | The snail is a small to medium sized mollusc that is generally split into three groups which are land snails, sea snails and freshwater snails. There are nearly 1,000 different species of snail that are spread throughout the world's continents. The snail is found on every continent on Earth with the possible exception of Antarctica, although it is thought that there are a number of marine snail species inhabiting the chilly waters that surround the South Pole. Although snails are found across a wide variety of habitats, they are most commonly spotted lunching in areas where there is plenty of vegetation.

Snails are distinctive animals due to the fact that they have a hard, coiled outer shell when they reach adulthood. All true snails are known to have large protective shells that they are able to retract their bodies into for protection. Snails that do not have a shell are not snails, but slugs. In order to break down their food, most snails have thousands of microscopic tooth-like structures located on a ribbon-like tongue called a radula. The radula works like a file, ripping the food into small pieces for the hungry snail.

Snails are generally herbivores, primarily eating vegetation such as leaves, stems and flowers. Some larger snail species however, are known to be more predatory animals either being omnivores or, in some cases, full-on carnivores. Due to their relatively small size, and slow paced movement, snails are preyed upon by numerous animal species all around the world. Rodents, birds and amphibians such as frogs and toads are some of the snail's main predators, and also fish for those snails that are inhabiting marine environments.

Despite being hermaphrodites (meaning that they possess both male and female reproductive organs), snails have to mate with another snail in order to fertilise their eggs. Up to a month after mating, the snails lays small white eggs into a burrow in the ground or on a covered leaf, which hatch after a couple of weeks. Baby snails can take up to two years to reach full adulthood. Today, snails are thriving in some areas of the world but are suffering in others. This can be for a number of reasons which include pollution, habitat loss or changes to the native food chain.

Oyster

 

True Wild Life | Oyster | The oyster is a sessile (immobile) mollusc that is commonly found clinging onto shipwrecks, debris and harbour walls around the world. Oysters are bivalve molluscs meaning that they are closely related to other animals such as scallops, clams and mussels. Oysters are found in salt water environments all around the world but are more commonly found in more temperate regions where the shallows are richer in nutrients. Oysters are thought to be among the oldest animals on the planet although their exact evolutionary path remains unclear.

As with other molluscs, oysters filter water in and out of their protective shells so that their vulnerable bodies inside are never put in danger. The hard shell of the oyster is primarily made up from calcium. Despite there being numerous different species of oyster, oysters are generally split up into four distinct groups, which are true oysters (the ones eaten by humans), pearl oysters (produce pearls), thorny oysters (also known as spiny oysters) and saddle oysters (have very thin shells).

Oysters are filter-feeders so collect their nutrients by taking in water and their gills filter and collect food that the stomach then digests, dispersing the remaining water out of it's shell. Oysters are thought to be able to process up to 10 litres of water an hour so can vary in quality depending on the quality of the water. Due to their small size and the fact that they don't move once they are adults, oysters are preyed upon by numerous different predators both in the sea and on the land. Humans, birds, marine mammals, sea turtles and various species of fish all prey upon the oyster.

Oysters have varying methods of reproduction. as some oyster species are hermaphrodites and some have separate sexes. Female oysters release millions of eggs into the water, where fertilization occurs externally. The oyster larvae develop within a matter of hours, and spend their first few weeks swimming around until they finally settle and attach themselves to objects, where they remain for the rest of their lives. Today, although now commercially farmed, wild oysters are becoming rarer mainly due to increasing levels of pollution. Although many oysters have adapted to life in poor quality water, they are not as healthy as those oysters that are filtering water that is chemical-free.

Octopus

 

True Wild Life | Octopus | The octopus group makes up around a third of the worlds cephalopod population, with around 300 species found in waters around the world. The octopus can be found in the all the worlds oceans, with the octopus ranging in size from a just few centimeters to number of feet depending on the species of octopus! The octopus often has a sharp beak, and an octopus will always have eight arms (unless any have been lost). Most species of octopus generally have arms with circular sucker pads on.

The lifespan of the octopus depends on the species of octopus, with many species of octopus averaging around 6 months old. Some species of octopus however, particularly the bigger octopus species, can live for a few years. The octopus is well known for being a master of disguise and is able to blend into pretty much any background using its elaborate camouflage. The octopus not only uses this to its advantage for both hiding from potential prey and predators, but it is also thought to play a role in the male octopuses mating display, in order to attract a female octopus.

The octopus is also thought to have three hearts, two of which are used for pumping blood through the gills, and another for pumping the pale blue blood of the octopus through the rest of the body.

Generally, most species of octopus have no internal or external skeleton which means that the octopus is able to squeeze itself into tight places. The octopus is known to be one of the most intelligent of all the invertebrates and the octopus uses this to its advantage mainly using elaborate disguise.

Giant Clam

True Wild Life | Giant Clam | The giant clam is the largest immobile mollusc in the world, with the occasional giant clam individual reaching nearly 6ft in length. Once the giant clam has settled somewhere the giant clam remains there for the rest of its life. Giant clams are founded anchored to the coral reefs in the warm, tropical waters of the Indian and South Pacific oceans, where giant clams spend the majority of their time feeding on the abundant variety of food that a coral reef has to offer.

Due to the large size of the giant clam, there have been reports of giant clams eating human beings. Despite this though, no reports of man-eating giant clams have ever been verified as it is thought that the giant clam would simply hide in its shell rather than attack an approaching human. Giant clams are thought to grow to such enormous sizes due to the fact that giant clams consume a great deal of sugars and proteins that are produced by the algae that live on the giant clams.

Although giant clams are omnivorous animals and therefore eat a mixture of both plant and animal matter, the nutrients produced by the algae provide the main source of food for the giant clam. Giant clams are also known to eat small food particles and animals that are present in the surrounding water. Despite the vast size of the giant clam, giant clams are preyed upon by a number of marine predators, many of which are actually much smaller in size than the giant clam itself. Eels, snails, fish and starfish are all known to snack on small parts of the giant clam.

Giant clams are also preyed upon by humans, who catch the giant clams in order to feed on a particular muscle which is seen as a culinary delicacy in many countries. The excessive harvesting of giant clams by humans has led to rapid declines in the world's giant clam population. Giant clams have both male and female reproductive organs but are not thought to self-fertilise. Giant clams release eggs and sperm into the water, where the eggs will generally be fertilised by the sperm from another giant clam. Giant clams are able to release more than 500 million eggs at a time.

Once fertilised, the eggs of the giant clam float around in the water for around 12 hours when the larvae hatches out. The giant clam larvae than begins to produce a shell and with just a few days, is big enough to find somewhere to settle on the sea floor. Once a giant clam has found somewhere in the reef that it likes, it anchors itself onto the reef where it remains for the rest of its life. Giant clams are so successful within their environment that it is not uncommon for these giant molluscs to live for more than 100 years!

Giant African Land Snail

True Wild Life | Giant African Land Snail  | The giant African land snail, is the largest species of snail found on land and generally grow to around 20 cm in length. The giant African land snail is native to the forest areas of East Africa but has been introduced into Asia, the Caribbean and a number of islands in both the Pacific and the Indian oceans. The giant African land snail is generally seen as a pest as these snails will eat almost anything vegetarian that they can find and have proven to be quite destructive when around crops and wild flowers. Giant African land snails are also known to carry parasites and are illegal to keep as pets in some countries such as the USA.

The giant African land snail is native to humid, forest areas but can today be found in agricultural areas, coast land, natural forest, planted forests, shrublands, urban areas, and wetlands. The giant African land snail is seen to be highly invasive species and large colonies of land snails can be formed from just one individual. Giant African land snails have both male and female reproductive organs. Although giant African land snails primarily mate with one another, in more isolated regions the giant African land snail is capable of reproducing by itself. Giant African land snail lay around 6 clutches of eggs every year, laying an average of 200 eggs per clutch. Around 90% of snail hatchings survive meaning that a snail free area can quickly become infested.

Giant African land snails are active during the night and spend the daytime hours safely buried underground. Giant African land snails reach their adult size by the time they are 6 months old and although their growth rate slows at this point, giant African land snails never stop growing. Most giant African land snail reach between 5 and 6 years of age but some giant African land snail individuals have been known to be more than 10 years old. During periods of extreme drought, the giant African land snail goes into aestivation (summer sleep). The giant African land snail seals itself inside it's shell to retain water and giant African land snails do this about 3 times a year, depending on the areas in which they inhabit.

Cuttlefish

True Wild Life | Cuttlefish | Cuttlefish are found in large numbers throughout the world's ocean waters from the warm, tropical shallows to the cold depths of the deep ocean. Cuttlefish are well known for the "flashing" colours that are displayed on their bodies during fighting and mating. In the same way as squid and octopuses, the cuttlefish also has an ink sack which ejects ink in order to fool oncoming predators.

The cuttlefish is a small-medium sized mollusc that is found throughout the ocean waters of the world. In the same way as their squid and octopus relatives, cuttlefish have a large, elongated body with tentacles surrounding their mouths.

There are 120 known species of cuttlefish found across the globe which vary in size from just 15 cm to the Australian giant cuttlefish which is often half a meter in length (not including its tentacles) and weighs more than 10kg.

The cuttlefish is a carnivorous animal that primarily preys on small crustaceans such as shrimp and crabs, but the cuttlefish also eats alot of fish. The cuttlefish uses its ability to change body colour to hide itself, before catching its prey with the sucker-pads on the end of its long tentacles which bring the prey into the sharp beak of the cuttlefish.

Due to the generally relatively small size of the cuttlefish, there are numerous marine predators that hunt them. Large fish, sharks and even other cuttlefish (sometimes of the same species) are the most common predators of the cuttlefish along with humans who hunt the cuttlefish around the world.

During the mating season, male cuttlefish change their body colours in order to successfully attract a female. Some male cuttlefish have even been known to make themselves look like female cuttlefish in order to trick the dominant males and stealing their mates. The female cuttlefish lays around 200 small eggs and sadly dies soon afterwards.

Blanket Octopus

True Wild Life | Blanket Octopus | This is one weird open ocean octopus! It looks like the Batman symbol flying through the ocean. It's common name, Blanket octopus, comes from their large web which they use to glide through the ocean. Blanket octopuses are rarely observed, but when people see them they notice. One, complete with eggs, washed up in Bermuda while I was off island on vacation. It made the local news and was the talk of the island. Another was recently (Sept 2009) spotted in St. Thomas, USVI.

The blanket octopus (Tremoctopus violaceus) is a rarely encountered pelagic species that spends its entire life cycle in the open ocean (Norman et al. 2002). Until the first observation of a living male off the northern Great Barrier Reef, Australia (Norman et al. 2002), males were known only from dead individuals picked up in trawls and plankton nets. Like other pelagic octopus species, T. violaceus exhibits sexual size dimorphism. The degree of sexual size dimorphism in this species, however,  is extraordinary: Females may reach 2 m in length whereas the reproductively mature male collected by Norman et al. was just 2.4 cm long. Individual weights of males and females differ by a factor of at least 10,000 (Norman et al. 2002).

Tremoctopus violaceus lives in the open ocean often in deep water (120-750 m) in the Mediterranean and the North and South Atlantic Ocean. The offspring are likely planktonic given the small size of the eggs. These octopuses may reproduce more than once but no one really knows much about their life history.