The blue whale, the largest known living animal on our planet, can be as large as an aeroplane and can weigh around 200 tonnes! A newborn blue whale is as big as a bus! What is interesting is that these giants mainly feed on tiny, shrimp- like sea animals called krill, which they filter out of the water in their mouths. They can eat around four tones of krill on a day!

1. Blue Whales Can Grow More Than 100 Feet Long

They are gigantic. Generally ranging in length from 80 to 100 feet (24 to 30 meters), the longest one ever recorded was a magnificent 108 feet (33 meters) long. That's about as long as three school buses lined up end to end.

2. They Can Weigh as Much as 30 Elephants

The average weight for these gentle giants is 200,000 to 300,000 pounds (90,000 to 136,000 kilograms), or about 100 to 150 tons. Some can weigh as much as 441,000 pounds (200,000 kg), or 220 tons. For comparison, an adult African bush elephant weighs up to 6 tons, so it may take 30 or more elephants to equal the weight of one blue whale.

3. They Have Big Hearts

The blue whale's heart is huge. It's the largest heart in the animal kingdom, weighing about 400 pounds (180 kg) and roughly the size of a bumper car. As a blue whale dives to feed, its giant heart may only beat twice per minute.

4. They Have Big Tongues, Too

A blue whale’s tongue alone can weigh as much as some elephants.

5. They Have the Biggest Babies on Earth

Blue whale calves are the biggest babies on Earth, easily, and at birth already rank among the largest full-grown animals. They pop out at around 8,800 pounds (4,000 kg) with a length of some 26 feet (8 meters). They gain 200 pounds (90 kg) a day! Their growth rate is likely one of the fastest in the animal world, with a several billion-fold increase in tissue in the 18 months from conception to weaning.

6. They’re Unusually Loud

Blue whales, in fact, are the loudest animals on the planet. A jet engine registers at 140 decibels; the call of a blue whale reaches 188. Their language of pulses, groans, and moans can be heard by others up to 1,000 miles (1,600 kilometers) away.

7. They Eat a Lot of Krill

Blue whales feast on krill; their stomachs can hold 2,200 pounds (1,000 kg) of the tiny crustaceans at a time. They require almost 9,000 pounds (4,000 kg) of the little guys a day, and around 40 million krill daily during the summer feeding season.

8. They're Pretty Fast

They travel a lot, spending summers feeding in polar regions and making the long trip to the equator as winter comes along. While they have a cruising speed of 5 mph (8 kph), they can accelerate up to 20 mph (32 kph) when needed.

9. They Have Long Life Spans

Blue whales are among the planet’s longest-lived animals. Kind of like counting tree rings, scientists count layers of wax in the ears and can determine a ballpark age. The oldest blue whale they’ve discovered this way was calculated to be around 100 years old, though the average life is thought to last around 80 to 90 years.

10. They Once Were Abundant

Before whalers discovered the treasure trove of oil that a blue whale could provide, the species was plentiful. But with the advent of 20th-century whaling fleets, their population plummeted until finally receiving worldwide protection in 1967. From 1904 to 1967, more than 350,000 blue whales were killed in the Southern Hemisphere, according to the World Wildlife Fund. In 1931, during the heyday of whaling, an astounding 29,000 blue whales were killed in a single season.

11. Their Future Remains Uncertain

While commercial whaling is no longer a threat, recovery has been slow and new threats plague blue whales, like ship strikes and the impact of climate change. There is one population of around 2,000 blue whales off the coast of California, but all told there are only around 10,000 to 25,000 individuals left. The International Union for Conservation of Nature lists the species as endangered. Hopefully with time, the planet’s largest gentle giants will again roam the seas aplenty.

Save the Blue Whale

  • Look for seafood certified by the Marine Stewardship Council (MSC), which can help reduce the prevalence of fishing gear known to entangle blue whales.
  • If you ever see a blue whale, keep your distance — for its safety and yours.
  • Watch your speed and keep a sharp lookout if you're ever on a watercraft in potential blue whale habitat. Boat collisions can seriously injure blue whales.

Credit :  Treehugger.com

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Zooplankton is an aquatic microorganism that drifts with water currents. It is one of the two types of plankton, the other being phytoplankton, a plant variety. Zooplankton and other small marine animals consume phytoplankton. They themselves become food for fish, crustaceans, and other larger creatures. As an intermediary species, zooplankton plays a crucial role in the aquatic food chain. As ocean waters warm, studies suggest zooplankton is travelling towards the Poles, which could end in an ecological collapse.

Body size has been defined as a "master trait" for plankton as it is a morphological characteristic shared by organisms across taxonomy that characterises the functions performed by organisms in ecosystems. It has a paramount effect on growth, reproduction, feeding strategies and mortality.One of the oldest manifestations of the biogeography of traits was proposed over 170 years ago, namely Bergmann's rule, in which field observations showed that larger species tend to be found at higher, colder latitudes

Zooplankton are generally larger than phytoplankton, mostly still microscopic but some can be seen with the naked eye.Many protozoans (single-celled protists that prey on other microscopic life) are zooplankton, including zooflagellates, foraminiferans, radiolarians, some dinoflagellates and marine microanimals. Macroscopic zooplankton include pelagic cnidarians, ctenophores, molluscs, arthropods and tunicates, as well as planktonic arrow worms and bristle worms.

Zooplankton is a categorization spanning a range of organism sizes including small protozoans and large metazoans. It includes holoplanktonic organisms whose complete life cycle lies within the plankton, as well as meroplanktonic organisms that spend part of their lives in the plankton before graduating to either the nekton or a sessile, benthic existence. Although zooplankton are primarily transported by ambient water currents, many have locomotion, used to avoid predators (as in diel vertical migration) or to increase prey encounter rate.

Ecologically important protozoan zooplankton groups include the foraminiferans, radiolarians and dinoflagellates (the last of these are often mixotrophic). Important metazoan zooplankton include cnidarians such as jellyfish and the Portuguese Man o' War; crustaceans such as cladocerans, copepods, ostracods, isopods, amphipods, mysids and krill; chaetognaths (arrow worms); molluscs such as pteropods; and chordates such as salps and juvenile fish. This wide phylogenetic range includes a similarly wide range in feeding behavior: filter feeding, predation and symbiosis with autotrophic phytoplankton as seen in corals. Zooplankton feed on bacterioplankton, phytoplankton, other zooplankton (sometimes cannibalistically), detritus (or marine snow) and even nektonic organisms. As a result, zooplankton are primarily found in surface waters where food resources (phytoplankton or other zooplankton) are abundant.

Just as any species can be limited within a geographical region, so are zooplankton. However, species of zooplankton are not dispersed uniformly or randomly within a region of the ocean. As with phytoplankton, ‘patches’ of zooplankton species exist throughout the ocean. Though few physical barriers exist above the mesopelagic, specific species of zooplankton are strictly restricted by salinity and temperature gradients; while other species can withstand wide temperature and salinity gradients. Zooplankton patchiness can also be influenced by biological factors, as well as other physical factors. Biological factors include breeding, predation, concentration of phytoplankton, and vertical migration.The physical factor that influences zooplankton distribution the most is mixing of the water column (upwelling and downwelling along the coast and in the open ocean) that affects nutrient availability and, in turn, phytoplankton production.

Through their consumption and processing of phytoplankton and other food sources, zooplankton play a role in aquatic food webs, as a resource for consumers on higher trophic levels (including fish), and as a conduit for packaging the organic material in the biological pump. Since they are typically small, zooplankton can respond rapidly to increases in phytoplankton abundance, for instance, during the spring bloom. Zooplankton are also a key link in the biomagnification of pollutants such as mercury.

Zooplankton can also act as a disease reservoir. Crustacean zooplankton have been found to house the bacterium Vibrio cholerae, which causes cholera, by allowing the cholera vibrios to attach to their chitinous exoskeletons. This symbiotic relationship enhances the bacterium's ability to survive in an aquatic environment, as the exoskeleton provides the bacterium with carbon and nitrogen.

Credit : Wikipedia 

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The octopus is a surprisingly complex creature and, quite possibly, the world's original "blue blood." Its 500 million neurons are distributed throughout its head and body, compared to the 100 billion neurons in our brains. The octopus's brain power isn't easily apparent at first glance, but it's proven itself capable of planning, reasoning and -- predicting sporting matchups. On the planning front, researchers have discovered that octopuses in Indonesia will gather coconut shell halves in preparation for stormy weather, then take shelter by going inside the two pieces of shell and holding it shut.

So what makes these smart sea creatures so adaptable? The ability is literally in their blood. The same pigment that gives the octopus blood its blue color, hemocyanin, is responsible for keeping the species alive at extreme temperatures. Hemocyanin is a blood-borne protein containing copper atoms that bind to an equal number of oxygen atoms. It's part of the blood plasma in invertebrates.

Blue-hued hemocyanin binds to oxygen in the blood and transports it throughout the octopus's body to supply tissues, a critical factor in its survival. Octopuses have three hearts and need more oxygen than most other invertebrates, so the hemocyanin allows octopuses to get a steady oxygen supply, even when it isn't readily available in their environment. It also ensures that they survive in temperatures that would be deadly for many creatures, ranging from temperatures as low as 28 degrees Fahrenheit (negative 1.8 degrees Celsius) to superheated temperatures near the ocean's thermal vents.

Researchers suspect the "blue blood" adaptation is the result of the octopus's inability to migrate away from challenging environmental conditions.

Credit : How stuff works

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A Dugong (family: Dugongidae) is the only herbivorous marine mammal found in deep waters. Dugong is a mammal that is closely related to elephants. It is a huge bulbous animal who is usually grey brown in color. Like whales, they have flattened fluked tail, a distinctive head shape, paddle like flippers but do not have any dorsal fin. The dugong is a marine mammal that is the only herbivore found in the deep waters that eats seagrass. Dugongs, even though they resemble a manatee, do not belong to the family of manatees. They weigh less than manatees and have different physical characteristics. Their rarity and the decreasing population are a great threat to their extinction. Issues like degradation of sea beds and illegal fishing traps are a major threat to the Dugong population.

There are very few dugongs that live in shallow waters of Australia, the Indian, and Pacific Ocean. Dugongs are listed as creatures that are vulnerable to extinction by the IUCN Red List. The numbers of these beautiful sea creatures are decreasing day by day due to the loss of seagrass beds and pollution of water which disrupts their habitation. Illegal fishing and fishing of dugongs for consumption and trade also is causing their population to decrease. They cannot live in freshwater and can tolerate marine water. Dugongs communicate by emitting sounds which are similar to chirps, whistles, barks that travel through water. They also communicate through sounds that echo underwater. They are also found in oceans around United States.

A dugong is a marine mammal that is native to the Great Barrier reef, world’s largest coral reef in the continent of Australia. The coastal shallow water around Australia were home to more than 85,000 animals but dugong populations are constantly decreasing across the world and they are highly endangered. The dugong species is hunted to extinction as well as traded to different countries illegally. Dugongs mostly live a sedentary lifestyle and migrate for miles in search of seagrass. Some dugongs prefer living in pairs, while sometimes, a herd of 7-10 Dugongs can be seen habituated. The herd or a group of dugong is called a nutcluster.

Dugongs have a lifespan of 70 years and give birth to only one calf during reproduction. They spend most of their time nursing and tending to their offspring. Low litter count and elongated weaning periods are also the reason why the gugong population is depleting. Young dugong calves are easy prey for crocodiles and sharks, which again contributes to population decrease.

Credit :  Kidadl

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Where can we see funnel-web spiders?

The funnel-web spiders get their name from their webs which are shaped like a funnel. The funnel’s mouth opens wide, and the spider sits patiently in the narrow part. When an insect prey touches the web, the spider rushes out to capture it. At least 40 species have been identified among these spiders, several of them carrying highly toxic venom. Especially dangerous is the male of Atrax robustus, or the Sydney funnel-web spider, which has caused many deaths. It has become part of Sydney’s folklore. An antivenom for its toxin was introduced in 1981.

Funnel-web spiders mainly live in eastern Australia, in the moist forest regions and highlands. They can be from 1 cm to 5 cm in body length, with the females more heavily built than the males. The front part of their body is covered with a carapace which is sparsely haired and glossy, and the colour of the body can vary from black to brown.

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