Creature Feature #397: Krill

Krill are tiny crustceans occuring in every ocean, worldwide. They play a critical role in the ecosystem. Krill feed on phytoplankton, and occasionally zooplankton. In turn they are preyed  upon by fish, mammals, birds, cephalopods and other arthropods. During the night they migrate towards the surface, sinking deeper into the depths during the day. More than half the population is predated each year, requiring a fast and fecund life-cycle. Climate change poses a threat to Krill populations, as can other disturbances.

Creature Feature #356: Jellyfish

Jellyfish are free-swimming marine animals, characterised by their gelatinous dome with trailing curtain of tentacles. They swim by sending pulses through the dome, propelling them forward. Jellyfish are ancient and primitive creatures, lacking in a respirative system. Their body is thin enough to oxygenate via diffusion - allowing them to absorb oxygen directly from the water. The tentacles are equipped with stingers to help them catch and stun prey. If food is adequate, they will spawn daily, with individuals simultaneously releasing their eggs or sperm into the water. They can also reproduce asexually by budding.

Creature Feature #321: Horseshoe Crab

Despite its name, the Horseshoe Crab is not a crustacean but belongs to an ancient Class of arthropods known as Xiphosura, of which there are only two surviving species. They are, in fact, more closely related to spiders than crabs. These bizarre creatures spend most of their lives at sea, swimming upside down and foraging on the sea bed for worms and molluscs. Once a year, however, they come ashore in great numbers to breed. The male finds and mount a female, fertlizing her eggs as they are laid then buried in the sand. Females can lay 120,000 eggs in this one night - which is a good thing, because the next day the sea birds descend to feast. Horseshoe Crabs will occasionally by upended, and once on their back they rely on their long tail to help them back upright again. Those with broken tails are likely to become dessicated beneath the sun.

Creature Feature #238: Flatworm

There are thousands of species of Flatworm: some are parasitic, others are free-living predators. The free-living ones are rather more pleasant to both look at and draw and they mostly occur in the sub-division Turbellaria. Flatworms are characterised by their bilateral symmetry: their right side mirrors their left and they have three cell layers. They lack a body cavity and contain no specialised respiratory or circulatory organs. Thus they use their entire body to breathe, and if they dry out then they will die, thus species are found in water, damp forest, or the intestinal tracks of other creatures. The predatory Turbellaria species use cilia or body contractions for locomotion. Some species even throw a thread of mucus for them to climb up. Mouths are often located on the underside of the body, and sometimes very large.

Flatworms are hermaphrodites, and can be both male and female simultaneously. To mate some species engage in "penis fencing" in which the winner gets to be the male for the encounter, and the loser adopts the female role and must carry the eggs.

Creature Feature #227: Fanworm

Fanworms are an Order of annelid worm, characterised by their fan-like appearance. Their first two body segments are fused, with feathery tendrils that allow them to filter feed. To protect their lower end, they construct a parchment-like tube from debris around them, such as sand and shell fragments, cementing them together with mucus. This they retreat into when not feeding. There are numerous species, with some - like this Mediterranean Fanworm - having only one fan, whereas other species have multiple or spiral fans. The Mediterranean Fanworm is found in shallow estuaries, living at depths of up to 30 m and growing up to 40 cm tall.

Creature Feature #221: Fairy Shrimp

The tiny Fairy Shrimp are an Order of crustacean. She can be found in ephemereal, or "vernal", pools in habitats as diverse as desert pools and mountain tarns. Fairy Shrimp lack a carapace. She feeds swimming upside-down, filtering organic particles from the water, or will graze upon algae. Her role in the food chain is an important one, and she is preyed upon by many fish and bird species.

Creature Feature #212: Emperor Shrimp

Emperor Shrimp are a tiny - less than 2cm long - crustacean widely distributed across the Indo-Pacific. He forms a commensal relationship with a host, such as a nudibranch or sea cucumber. Scurrying along this larger creature, he feeds on its waste products whilst also keeping it clean of parasites. He is an omnivore and a detrivore. If danger threatens, he will scurry beneath his larger host, or bury himself in the substrate. Emperor Shrimps have found their way into marine aquariums, but very little seems to be known about them and they are very reliant on the presence of a potential host species.

Creature Feature #206: Elysia

Elysia are a Genus of sea slugs that graze on algae. Some species hijack the chloroplast from the plant matter, using it to coat the inside of their digestive tract and allowing them to survive on photosynthesis. This chlorophyll affects their colour, making them the vibrant green. Elysia are hermaphrodites, and are able to self-fertilise, but do so very rarely, preferring to mate with another individual. Eggs are laid in a long string, and these hatch into a shelled larva.

Creature Feature #188: Earwig

There are about 2,000 species of Earwigs, spread throughout the world and characterised by the large pincers that grace their abdomen. Nocturnal in nature, she hides within crevices during the day, favouring the damp and the dark. At night she ventures out to chew her way through foliage and flowers and is charged with damaging crops. She is a protective mother, driving her mate away shortly before laying her eggs. These she protects from predation, keeps them clean from fungi growth and may help her nymphs hatch - which they do after 7 days. Their first meal is their egg casings, and the mother proceeds to reguirgitate further meals for them. They grow through several moults, eating their old skins, until they attain their adult stage. If their mother dies before they mature, they may eat her.

Creature Feature #187: Earthworm

The Earthworm is a blind tube-shaped Annelid, usually found in the soil. Their diet consists of organic matter, both live and dead. Earthworms are hermaphrodites and capable of regenerating lost segments. It is a common belief that a worm split in half will regnerate into two worms, this is - for the most part - a myth, although if it were, theoretically, bissected in the right place, it is possible. For the most part however, one end will regenerate and the other end will die. Reproduction occurs above ground, usually at night. The eggs develop inside the clitellum - the thickened "saddle" near the head end of the worm - which they then slip out of, leaving behind as an incubator in which the offspring can develop. When the juveniles emerge, they resemble tiny adults. Earthworms have a simple digestive structure and play a major role in soil fertilisation. They are commonly used to decompose food scraps.

Creature Feature #181: Dung Beetle

The Dung Beetle plays an important role as nature's "clean-up crew". His diet consists partly, or entirely, upon the feces of vertebretes, specifically herbivores, althogh some species supplement their diet with mushrooms, decaying leaves and fruit. He uses his sensitive sense of smell to locate the dung and then rolls it up into a ball - sometimes up to ten times his weight. Sometimes the male and the smaller female will roll the ball together, with her riding on top, or following behind and occassionally assisting. The ball is always rolled straight, regardless of any obstacles. It will be buried in a soft patch of soil and the pair will then mate, the eggs being laid inside this warm brood ball. They then remain to guard their developing larvae.

Creature Feature #166: Domino Beetle

The Domino Beetle is so named for the ten distinctive spots upon his back. He can be found across Yemen, Saudi Arabia, Egypt, Iran, Iraq and the UAE, where he colonises desert scrubland and plains. Well adapted for a terrestrial existence, has has long, slender legs and strong eyesight to help him hunt for prey. If threatened, he can squirt jets of formic acid to burn the potential predator and also creating a foul aroma. Nocturnal in nature, he remains hidden away during the daylight hours. During the night he hunts for smaller invertebrates.

Creature Feature #151: Daphnia

The Daphnia is a tiny crustacean, measuring no more than 5mm in length; she is a component of plankton. Various species populate different habitats - from freshwater to marine, including acidic swamps. Sometimes referred to as "water fleas" her motion through the water somewhat resembles that of a flea. Many species are translucent, which makes her popular with scientists as one can study her entire system, including her beating heart - which leads to studying the effects of caffeine and nicotine on heart rate. Reproduction is both asexual and sexual . Eggs are released regularly with each moult, but towards the end of the growing season she produces a few male offspring which fertilise the last, hardier eggs so that they will withstand harsher conditions.
(I'm confused too, crustaceans are weird)

Creature Feature #137: Cricket

The Cricket is a nocturnal insect noted for his strident, chirping call. A long toothed vein runs along the bottom of each wing, and he runs the top of his wing across it. The wings themselves act to amplify the sound. This song serves multiple purposes - attracting a mate; warning off rival males - he even performs after a successful mating. He has powerful jaws and feeds on a diet of dead organic matter, fungi and plants. He, in turn, becomes part of the food chain, being eaten by lizards, birds, small mammals and even humans.

Creature Feature #136: Crawdad/Crayfish

Crayfish, or Crawdad, is the name commonly given to freshwater lobsters. These crustaceans make their home in bodies of water that do not freeze to the floor, with a preference for running water and lots of crevices to hide in. An omnivore, she feeds predominently on dead plant and animal matter, along with anything living she can locate as she scuttles across her aquatic habitat. She is vulnerable to pollution, and also features on menus across the world.

Creature Feature #134: Crab Spider

Crab Spider is a fanciful name commonly given to members of the Thomisidae Family, for their crab-like appearance or tendency to sit with their front legs slightly raised. Predominently, she is an ambush hunter, hiding amongst flowers and waiting for insects to drop by. Some species are even known to change colour, camouflaging with their flower haunts, whereas others resemble bird roppings. Her flattened body allows her to crawl into narrow crevices and hide in small cracks. Her front legs are very strong, and when she locates her prey she snatches it close, incapcitating it with a venomous bite. Although they do not build webs, Crab Spiders use their silk as drop lines, lowering themselves into new hunting environments.

Creature Feature #133: Crab

There are numerous and diverse species of Crabs -colonising the ocean, the shore, rivers and even forests. They are characterised by a hard body and five pairs of limbs, the front two of which are developed into chelae (the scientists name for "pincers"). He uses these for defense and also in communication. Due to his leg articulation, it is faster and easier for him to scuttle sideways, but some crabs have been shown to walk forward. He starts life as a free-swimming larvae and undergoes several moults before achieving his adult form. During these moults his old shell softens and another forms underneath, then the old splits and he must crawl out. This is a slow and difficult process, and he may become stuck and perish. He then hides away whilst his new shell stretches and hardens. This colourful chap is known as the "Sally Lightfoot Crab".

Creature Feature #126: Coral

Each Coral is made up of thousands of tiny, genetically identical individuals called polyps. Each measures no more than a few mms in diameter and no more than a few cms in length. These polyps have feeding tentacles, a central mouth opening and a sturdy exoskeleton at their base. When combined into these mighty and colourful colonies they create a larger skeleton. Polyps can reproduce asexually, but during the full moon the various species will undergo a massive spawn, releasing their gametes into the sea for it to drift over to their related (as in same species) neighbours). Coral feed on small things that drift their way - microscopic plankton and even small fish. Like anenomes, they sting it with the tentacles and draw it down into their digestive tract. Coral reefs are under threat from mining, pollution and climate change and over 10% of the global reefs are dead.

Creature Feature #116: Coconut Crab

This freakish fellow is the largest land invertebrate in the world. His body can grow up to 40cm long, with the limbs extending him to 1m. A member of the Hermit Crab Family, when he is young he lives in empty gastropod shells, but as he matures he forms his own hard exoskeleton. He can be found on islands across the Indian Ocean, but on those with a large human population he has been extirpated (become locally extinct). This is, obviously, because a crab this big is going to find favour on the dinner table. He can climb trees and his claws are strong enough to crack coconuts, but coconuts do not form the major part of his diet. He prefers softer fruit, carrion and smaller crabs. They are likely responsible for the disappearance of many a shipwrecker-then-deceased sailor.  They will drown, which is a bit of an issue because they are still dependent on the ocean for reproduction. The eggs hatch into larvae where they grow through several stages. After about a month they find themselves a nice gastropod shell to wear and come ashore with other hermit crabs to begin their landlubber's life.

Creature Feature #88: Centipede

There are estimated to be at least 8,000 species of Centipede, spread throughout the world - with habitats ranging from withi the Arctic circle, to deserts and tropical rainforests. Lacking the waxy cuticle of insects and arachnids, Centipedes lose water rapidly through their skin and thus do require a moist micro-habitat: generally in soil or under leaf litter. Generally carnivorous in nature, Centipedes are generalists and will eat anything that they can catch and is soft bodied enough for them to consume. Although "centipede" translates as 100 feet, Centipedes can have anything from udner 20 to over 300 feet. Each pair is connected to a body segment and, due to the nature of their growth, Centipedes have an odd number of body segments. This fellow, the Chinese Red-headed Centipede can grow up to 20cm in length.