Invertebrates - Animal Questions.org

Do Spiders Have Brains?

Spiders, like humans have the same basic bodily systems that we do however they do not work in the same way and are also arranged differently throughout the body. In spiders what is known as the cephalothorax contains the brain, stomach, eyes, and mouth and the abdomen contains the heart, digestive tract, reproductive organs and lungs.

One of the most astounding things about spiders is that they are equipped with very small brains. However how much they can accomplish with such a small brain is almost unheard of! The spider’s central nervous system is made up of two relatively simple ganglia, or nerve cell clusters that are connected to nerves leading to the spider’s muscles and sensory systems. Some species of spiders have even exhibited learning behavior. For instance, if something isn’t working they will give up and try something new.

Are Crabs Arachnids?

Crabs are not arachnids; they are crustaceans. Arachnids are animals such as spiders. Arachnids, insects and crustaceans all belong to the family group arthropod. Arthropods are animals with exoskeletons, segmented bodies and jointed legs. They are the largest group of animals on Earth. Most crustaceans such as the crab are aquatic animals living in either marine or fresh water environments. While a few crustaceans such as terrestrial crabs and/or hermit crabs have adapted to life on land. Other crustaceans you may be familiar with include lobsters and barnacles.

Crustaceans can be recognized by their hard, external shell which protects their body. They are equipped with a head and an abdomen. Their heads include antennae which are a part of their sensory system. Their abdomen includes the heart, digestive system and reproductive system as well as appendages such as legs for crawling, swimming and climbing. Crabs love to climb. Many crustaceans have separate sexes and also reproduce sexually while a few others are hermaphrodites. Others have been known to change their sex during the course of their life.

Crustaceans such as the crab often have claws which help it crawl, eat, and defend itself against predators. Crabs usually pack quite a pinch. They burrow and can also run or walk sideways. These creatures can often live in extreme areas due to their ability to adapt to the changing environment. (An example of this would be the hermit crab which requires a temperature of 70+ degrees Fahrenheit and lots of moisture in order to live).

Can Jellyfish Live Out of Water?

Jellyfish do not have enough adaptations to live outside of water. In order to do this they would need an excretory system for the osmoregulation and a true ambulacral system. Jellyfish typically only live for about a year and if they do not live for about a year it is most likely because they were eaten by a fish, turtle, bird or something like that. Another way they can die early is if they are not in salt water. Jellyfish need saltwater in order to stay alive.

When a jellyfish gets washed up to shore it cannot get back into the water. If you spot one lying on the beach you should never touch it as it can still sting you, even if it appears to be dead or actually is dead. Something that is rather interesting though is that when jellyfish wash ashore, they melt. All that will be left is some of its skin.

Can Jellyfish Sting Even After They Are Dead?

There are approximately 2,000 species of jellyfish worldwide yet only less than 100 or so are actually thought of as dangerous and can cause harm to human and animal life. It is true that jellyfish can still sting even after they have died. This is because jellyfish do not consciously sting. Each of their tentacles can be equipped with stinging cells that automatically release venomous barbs when the cells come into contact with an object. This is done as a defense mechanism to keep jellies safe from predators. It does not work on sea turtles however. Interestingly enough these turtles can eat jellyfish without getting stung or poisoned.

What may come as a surprise to most is that jellyfish can even still sting you when they have died, washed up on a beach and dried up. The tentacles (even if they are no longer connected to the jellyfish) can still sting and it is for this reason that these jellyfish or their parts should never be picked up or stepped on. Some jellyfish are more poisonous than others; however all can cause quite a bit of pain if they sting an individual.

Are Snails Natural Decomposers?

Snails are among some of the most common natural decomposers which also consist of creatures such as bacteria, worms, slugs and fungi such as mushrooms. Decomposers are the last stop on the food chain and they tend to eat the things that no one else wants to. They may eat many dead things from the ground in order to get nutrients. These dead things that decomposers such as the snail eat are referred to as “detritus” meaning “garbage”.

If decomposers such as the snail did not do their job the producers would not get the nutrients that they need and would die. All living things would start to starve and eventually die if we did not have plants. Therefore decomposers play a crucial part in the food chain and are often referred to as being nature’s recyclers since they help keep the nutrients moving along the food web.

Decomposers such as the snail are equipped with very small bodies so that they can break down large pieces of dead things. If they did not decompose the ground would be covered with junk and the world would be a dirtier place than it already is. Snails can be found in places like the forest. Whenever something dies here, these decomposers break the decomposing material down in order to provide nutrients for the soil.

Since terrestrial snails are indeed natural decomposers, it comes as no surprise that they have a direct and positive effect on the forest’s health as well as the soil’s richness. In general, these snails are an important food source for animals such as birds which consume the shells of snails to help add calcium to their diet. They are also an important source of food for several species of salamanders, mice, shrews, wild turkey, grouse and a few songbirds. Overall snails are essential to the ecosystems in which they reside.

Do Crabs Feel Pain?

Virtually all animals, even crabs are able to feel pain. In fact, Not only do crabs feel pain, they are also able to retain memory of it. Both pain and stress are also key survival mechanisms for the crab. There have been experiments where hermit crabs have been electrically shocked and then provided with vacant shells afterwards. In which case they were all found to abandon their old shells and enter new ones, exhibiting stress related behaviors such as grooming of the abdomen or rapping of the abdomen against the empty shell.

Grooming for a crab can also be used as a protective motor reaction viewed as a sign of pain. Crabs are also equipped with a central nervous system and receptors that help them learn to avoid negative stimulus after experiencing such. Like humans if they are hurt they will limp or rub the appendages that are in pain. Studies have also shown physiological changes that occur within the crustacean including the release of adrenal like hormones that occur when pain or stress is suspected in the creature much similar to that of a human. Unfortunately for crustaceans such as the crab, they often become food for humans and sometimes are even boiled alive. In which case, they would feel pain! Perhaps this is something most of society should begin to consider.

Are Spiders Nocturnal?

When it comes to spiders, most species are nocturnal. However some species such as the jump spider or the garden orb weaver are diurnal. During their evolutionary history, some species of spiders have even changed from a nocturnal lifestyle to a diurnal lifestyle. The important change in their environment was irradiation by sunlight. Orb webs of diurnal spiders may be affected by exposure to ultraviolet irradiation whereas those of nocturnal species may be unaffected.

The effects UV rays have on the mechanical properties of spider silks is something that should be seriously considered. The webs of orb weaving spiders must trap insect prey, which closely relates to the breaking energy of the spider silk constituting the orb webs.

Are Snails Born With Shells?

Most snails are indeed born with a shell; this shell is known as a protoconch. The word protoconch literally means “first, earliest, or original shell” and is often used when referring to an embryotic or larval shell of some classes of mollusks. However starting off this shell is transparent and soft to begin with.

This requires snails to need a lot of calcium. This consumption of calcium then helps to harden their shells. In fact the very first thing a newly hatched snail often does is eat its own casing of its egg in order to absorb calcium and ensure good health, nutrition, and hardening of the shell. Some snails have even been known to become cannibals and eat the shells of their unhatched siblings.

Over the next three months or so the snail’s shell begins to thicken up and typically begins to grow into a spiral shape. However snails are also known to have different shaped shells and some come in rounded, flat, pointed or high spiraled shapes, it just depends on the species. When growing into a juvenile snail it will also eventually acquire the full adult coloration and an opening will be added to the shell. The part of the shell that the baby snail was born with typically ends up in the middle of the spiral. When some species of snails become too big for their shells they may abandon it and use one from another animal or a previous snail that has shed its shell.

Are Jellyfish Edible?

Very few jellyfish are actually edible. The scyphozoan jellyfish (about 12 of the 85 species or so) are one of the more popular jellyfish often harvested for food. Most of the harvesting takes place in locations such as Southeast Asia. Fisheries have also begun harvesting the American cannonball jellyfish located along the southern Atlantic coast of the United States and in the Gulf of Mexico to export to Asia because they are larger with more rigid bodies and their toxins are harmless to humans, making them a favored meal when compared to other types of jellyfish.

Traditional processing methods are carried out by a “jellyfish master” and involve a multi-phase procedure that takes 20-40 days. During this procedure the gonads and mucous membranes are removed, and then the umbrella and oral arms are treated with a mixture of table salt and alum then compressed. Processing reduces liquefaction, odor, and the growth of spoilage organisms and also makes the fish drier and more acidic which in turn produces a crunchy, crisp texture.

Jellyfish that are prepared this way retain 7-10% of their original weight the processed product contains approximately 94% water and 6% protein. Freshly processed jellyfish often has a white creamy color and will turn yellow or brown during prolonged storage. Despite their high water content, these creatures are actually quite nutritious. They are almost completely free of cholesterol, calories, carbohydrates and saturated fats.

In China, jellyfish are processed by being desalted first by being soaked in water overnight and then eaten raw or cooked. The jellyfish dish is often served shredded up with a dressing of oil, soy sauce, vinegar, and sugar. Or it is sometimes served as a salad with vegetables. In Japan, cured jellyfish are rinsed and then cut into strips and served along with vinegar as an appetizer. Desalted, ready to eat products are also another popular choice available for consumption. Some individuals prefer to cook jellyfish and then let it sit in cold water for about 8 hours, blanch it and add some seasonings to it. It is very important to keep cooked and raw jellyfish apart from each other. Even though they mostly contain water, they are still able to hold the same type of bacteria as other meats.

Are Bees Attracted to Certain Colors?

Bees are one of the main reasons that so many flowers are brightly colored. This is because they are attracted to the brighter colored flowers. As a result, these are the flowers that often get pollinated. Some colors have more influence on bees than others. Bees also see in a slightly different spectrum than humans. They are able to see into the ultraviolet part of the electromagnetic spectrum that we humans are not able to see. As a result of this type of vision, bees are also unable to see the color red, and are very attracted to the colors yellow and blue. The color black is a warning sign for them to stay away, this “warning” most likely evolved from the fact that many of their predators such as bears, etc. are a darker color. Seeing the color black for a bee is kind of its heads up to not enter.

It should be mentioned that the color of clothing that one wears will not directly influence an individual’s chances of getting stung by a bee per se, although you might find that more bees will be attracted to come into the area. The bright colors will not make bees sting any more than if they are around colors that are not bright. One of the main reasons people often get stung is because when a stinging insect comes into their vicinity they get scared and often act silly and do things that they shouldn’t which threaten the bee causing it to sting. If a person remains still and doesn’t agitate the bee, they will have better chances of not getting stung and the bee will most likely determine very quickly that there is no nectar to be found there and move along.