Marine Scotland: fishy facts

Do whales have belly buttons? How many teeth does a haddock have? Are there any fish that eat people?

These are just some of the questions that you'll find answers to.

This document is part of a collection


  • How many species of octopus are there? There are around 300 known species of octopus
  • How does an octopus change colour? It has special skin cells which allow it to change colour
  • How big can an octopus grow? The Giant Pacific Octopus is often considered to the be the largest octopus species. Adults usually weigh around 15 kg (33 lb), with an arm span of up to 4.3 m (14 ft). There’s a report of one being a massive 272 kg (600 lb) and having an arm span of 9 m (30 ft)!
  • What is octopus ink made of? Octopus ink is made of a number of chemicals, depending on the species. However, its main constituents are melanin and mucus.
  • Do octopus give birth to live young? No - the female lays about 200,000 eggs which she cares for, guarding them against predators, and gently blowing currents of water over them so that they get enough oxygen. The young larval octopuses spend a period of time drifting in clouds of plankton, where they feed on copepods, larval crabs and larval starfish until they are ready to be born
  • How many brains does an octopus have? Only 1, but it has three hearts that are in its head!
  • Would a great white shark eat a blue ringed octopus? Probably not
  • Is there a difference between a squid and a octopus? An octopus and a squids are both head-footed aquatic animals (cephalopods) but they differ in their physical characteristics, habitat and behavior. An octopus has a round head with eight arms. The arms are endowed with one or two rows of suckers but these never have hooks or sucker rings. Squids have a triangular shaped head and eight arms and they also have two fins on their head and two tentacles. The arms of a Squid have hooks and/or suckers or sucker rings.
  • Why does an octopus have three hearts? One of them pumps blood through the body, while the other two pump blood through the gills.
  • Is an octopuses blood the same colour as humans? Why does an Octopus have blue blood?  Octopus blood contains a lot of copper and because the oxygen it breathes is dissolved in plasma and not red blood cells, it gives the blood a bluish color.
  • Where is the blue ring octopus located? The blue-ringed octopuses are three (or perhaps four) octopus species that live in tide pools in the Pacific Ocean, from Japan to Australia (mainly around southern New South Wales and South Australia)
  • Why does an octopus need ALL those arms? They use their arms to do all kinds of helpful things. For example, octopuses are able to detach one of their arms from their body if the arm is caught by a predator! The arm continues to move even after it’s disconnected from the octopus’s body, which confuses the predator while the octopus make his or her escape! (The missing arm then grows back over time.) The arms also help them move around at the bottom of the ocean floor. The most arms ever recorded is 96!
  • What is the average life span of an octopus? Octopuses have a relatively short life expectancy, and some species live for as little as six months. Larger species, such as the Giant Pacific Octopus, may live for up to five years
  • How many suction caps are there on each octopus's legs? Lots and lots!


  • How do we know that coral is a living organism? Coral is a fantastic structure and live creature  - we know it is live because it grows (althought very slowly) and we can actually measure the living activity and also we see all the colours
  • Are there any endangered species of coral? General estimates show approximately 10% of the world's coral reefs are dead and another 60% of the world's reefs are at risk due to human-related activities. It's a particular problem in South Eeast Asia and it is possible that over 50% of the world's coral reefs may be destroyed by 2030. That's why most countries protect them through environmental laws
  • Are there any coral reefs around Scotland?   You do get corals in the waters around Scotland. They are called cold water corals and they are a very important habitat
  • Where is the biggest reef? The Great Barrier Reef is the world's largest coral reef system and has over 2,900 individual reefs and 900 islands stretching for over 2,600 kilometres (1,600 miles)


  • Is it true that turtles can live 125 years? Yes - it is true that turtles can live 125 years
  • How long can a turtle stay out of the water for? Turtles breathe air and do not lay eggs underwater, although many species live in or around water
  • How many species of turtle are there? Seven species of marine turtles are found worldwide. Of these, five have been recorded in Europe
  • Where do turtles have their babies? Sea turtles lay their eggs on dry, sandy beaches
  • How do turtles know which beach to come back to to lay their eggs? Scientists say that the sun, moon and stars help to guide them!
  • How hard is a turtle's shell? They’re really hard - like suits of armour


  • How many species of whale are there? About 80
  • How many grey whales are there in the world? Over 100, 000
  • What size is a whale when it is born? Blue whale calves are about 25 feet long (7.6 m) and weighs about 6-8 tons (5.4-7.3 tonnes) whereas a minke whale is only 9 feet (2.8 m) long and weighs about 1,000 pounds (454 kg)
  • How long do baby whales stay with their mothers?  They can stay for more than a year in many species
  • How much fish does a whale eat? Would a whale would eat a shark? They eat food ranging from microscopic plankton to very large animals. Toothed whales eat fish and squid, Killer whales sometimes eat other marine mammals, including whales and Baleen whales  eat mostly krill, which they swallow whole
  • Why do whales have blowholes? Why do whales squirt water out of the hole in their head?  Whales breathe through the blowholes; baleen whales have two and toothed whales have one. Breathing involves expelling excess water from the blowhole, forming an upward spout, followed by inhaling air into the lungs
  • How big can a blue whale get? Blue whales grow to be about 80 feet (25 m) long on average, weighing about 120 tons (109 tonnes)
  • How old do whales live to? Whale lifespans vary among species and it can be more than 70 or 100 years
  • Why do whales sing? Whale "singing" is likely to serve many purposes, including to tell other whales where they are, mating, and identification
  • How deep a whale can dive? Blue whales can dive for up to an hour, going to a depth of 350 feet (105 m).
  • How high can whales jump out of water? They can leap so that nearly half of their body clears the water!
  • Do whales have bellybuttons? Yes! (But they're v tricky to find!)
  • Can whales be dangerous? Although they are not aggressive towards humans, they can use their weight to hurt us and they have been known to eat sharks
  • Why do whales jump onto the sand and crush themselves? Whales have beached throughout human history, so many strandings can be attributed to natural and environmental factors, such as rough weather, weakness due to old age or infection, difficulty giving birth, hunting too close to shore and getting lost
  • Do barnacles cause problems for whales?   Nope - barnacles don't harm whales
  • How does the brain of a whale know to only sleep half at a time so it won't drown?  How can the two halves work separately? Scientists aren't sure, but they think that only one side of the whale's brain sleeps at a time, so they rest but are never completely asleep
  • Is it true that the biggest thing a blue whale can swallow is a grapefruit? Hmm, we’re not sure but an average-sized blue whale will eat 2,000-9,000 pounds (900-4100 kg) of plankton each day during the summer feeding season in cold, arctic waters (about 120 days).
  • Which countries hunt whales? What do they use the whales for? why do people fish for whales? The current whaling nations are Norway, Iceland and Japan and the aboriginal communities of Siberia, Alaska and northern Canada. They have been hunted commercially for whale oil, meat, baleen and ambergris (a perfume ingredient from the intestine of sperm whales) since the 17th century
  • Are whales in danger of becoming extinct?  Hopefully not but some species of large whales are listed as endangered
  • Where do Killer Whales live? Like many whales, killer whales live over a vast sea area.  Some of the whales make the longest migration of any animals


  • How small are plankton? You need a really, really powerful microscope to see them
  • Do plankton have any other purpose aside form being food for fish? As well as being food, plankton ecosystems help with many important chemical elements, including the ocean's carbon cycle
  • What is the lifespan of plankton? Not long - between 1 and 5 days


  • How can dolphins communicate with humans? Dolphins are capable of making a broad range of sounds and scientists believe that they communicate in a human-like system of signs, which helps us understand them
  • Is it true that a dolphin was given a new tail? Yes! A dolphin in a Japanese water park, who couldn't swim because it had no tail, was given an artificial fin made by the Japanese tyre manufacturer Bridgestone.
  • When dolphins are asleep, half of their brains sleep too, is this the same for fish? Why do dolphins sleep with one eye open? Generally, dolphins sleep with only half of their brain at a time, and the bits that's awake makes sure that it continues to breathe and to watch for possible predators and other threats.
  • Why do the Japanese hunt dolphins? In some parts of the world, such as Taiji in Japan and the Faroe Islands, dolphins are traditionally considered to be food
  • How long is a dolphin?  They are up to 9.5 metres
  • Are spinner dolphins are the most acrobatic dolphins? Yes, very possibly. They’re not the only ones, but the best known performers.


  • Why do crabs walk sideways? Because of the way their legs are attached, walking sideways is more efficient. However, some crabs walk forwards or backwards
  • What do crabs eat? Crabs are omnivores, feeding primarily on algae and taking any other food, including molluscs, worms and other crustaceans

Other sea life

  • Why do stingrays have flat bodies? We don’t know, but the flattened bodies of stingrays allow them to effectively conceal themselves in their environment. Stingrays do this by messing up the sand and hiding beneath it
  • Why and how do stingrays sting? They sting to protect themselves, if they are stepped on or if they are scared. Most stingrays have one or more barbed stings on the tail, which is used exclusively in self-defence. The stinger may reach a length of approximately 35 cm (14 in), and its underside has two grooves with venom glands
  • What is the biggest manta ray species? Manta rays are the biggest species of ray - The largest known specimen was more than 7.6 metres (25 ft) across, with a weight of about 1,300 kilograms (2,900 lb)
  • Are electric eels really electric? How? The electric eel is an electric fish which can generate powerful electric shocks, of up to six hundred volts, which it uses for both hunting and self-defense. It produces its own electricity within its body
  • How are sea shells made? Seashells are primarily made of calcium, a hard mineral, just as our own bones are
  • How do squid make their ink? Cephalopod ink (squid ink) contains a number of chemicals in a variety of different concentrations, depending on the species. However, its main constituents are melanin and mucus
  • Why does the male sea horse give birth to the young? Scientists don’t know although some researchers believe males can produce more offspring than females
  • Why do seahorses dance? Dancing is part of how they get to know each other and mate
  • Do copepods need air filtration? Copepods don't have gills because they can absorb oxygen directly into their bodies
  • Is there marine life on other planets? We do not know , but it is possible
  • What do sea snails eat? They mostly eat coral
  • What is the difference between a red lobster and a blue lobster? A blue lobster is alive a red one has been cooked
  • Why do mother seals leave their vulnerable pups on the beach? Seals will go loooking for food for their young and most baby seals stay with their mothers for 4 - 6 weeks
  • How many species of sea otter are there? There's one main and  3 related “sub” species
  • Do sea cucumbers eat their own poo? The diet of most cucumbers consists of plankton and decaying organic matter found in the sea, but I'm not sure about their own poo!
  • Why is seaweed so slimy? It is slimy to protect itself from parasites and from being eaten
  • How does seaweed grow in deep water? Sea weed can really only grow in the sunlit waters
  • What age can walrus's live to? A walrus can live for 20 - 30 years
  • How big can a neon tetris grow? What a great name, isn't it? It grows to approximately 3 cm (1.2 in) in overall length
  • How do oysters have pearls in their mouth? How do clams make pearls? Oysters have pearls because when grains of sand get caight inside them, to protect themselves by producing a substance which builds up in layers and makes an oyster


  • What is the lifespan of a star fish? Usually between 10 and 30 years
  • What are starfish made of? The bodies of starfish are composed of calcium carbonate components, known as ossicles
  • How do starfish breed? They breed externally by releasing eggs and sperm from their arms, which mix together
  • How can starfish's legs grow back? How long does it take for a starfish to grow back a limb?  The cells in their body start to grow again, a bit like when you form a scab over a cut. An arm can grow back on a few weeks
  • Is it true that one species of star fish can take over a whole reef? Some starfish likes coral and in the Great Barrier Reef off the coast of Australia, the Crown of Thorns starfish has been blamed for widespread reef destruction
  • How do starfish eat? The mouth of a starfish is located on the underside of the body, and opens through a short esophagus into a first and then a second stomach
  • Do Starfish have eyes?  On the end of each arm there is a microscopic eye which allows the sea star to see, although it only allows it to see light and dark, which is useful to see movement


  • How do jellyfish see what they are doing? Some jellyfish also have light-sensitive organs that do not form images but which can detect light. This helps them know  which way is up and which way is down, depending on sunlight shining on the water's surface. Certain species of jellyfish, such as the Box jellyfish, have 24 eyes, two of which are capable of seeing colour
  • How do jellyfish shock you? Why do jellyfish sting? Why does it hurt when jellyfish sting? Jellyfish sting their prey using  specials stinging cells in their bodies. Most jellyfish stings are not deadly and might not hurt but it can be very uncomfortable, very painful or can cause death. Even beached and dying jellyfish can still against sea wasp jellyfish waters by covering their exposed skin with ladies tights!  They only do it when they get scared and sometimes by accident
  • Why are jellyfish have bright colours/ Why are jellyfish are transparent? Some of them just are! The most colourful ones are found in warmer water, but some have no colour at all because jellyfish are made of 95% water, surrounded by two layers of protective skin.
  • How much do jellyfish eat in one day? What do jellyfish eat? Not too much - they aren’t very big. They are carnivorous (meat eaters), feeding on plankton, crustaceans, fish eggs, small fish and other jellyfish
  • How big can a jellyfish grow? The rarely-encountered deep-sea jellyfish is possibly the "largest jellyfish", with arms that are 100 centimetres (39 in) wide, and  6 metres (20 ft) long!
  • What is the most dangerous type of jellyfish? Is the wasp jellyfish the most dangerous sea creature? The Irukandji jellyfish from Australia are one of the worst. If you’re stung, the symptoms range from hours to weeks, and victims usually need to go to hospital
  • Why is wee the best thing to help a jelly fish sting?   Not all jellyfish are dangerous and they vary in size from the size of a pea to bigger than a dinner plate.  Some of these big jellyfish have long tentacles and within the tentacles is some really nasty poison.
  • Do Jelly fish have teeth? Nope! Jellyfish are unlike many other marine creatures as they do not have teeth, fins, scales or pincers - like crabs
  • Why do we sometimes see local swarms of jellyfish on our local beaches (Findhorn)? Climatic conditions can cause a huge bloom of jellyfish, but when the conditions change agin and or the food runs out, coupled with localised storms , causes lots of the jellfish to either die or be washed up on beaches  


  • Are any sharks are endangered? Yes, there are some endangered species, but the great white shark is the most
  • Do sharks eat each and would they eat their own species? Different sharks feed on different things. Some eat molluscs and crustaceans (shellfish), others eat fish and others on larger prey such as mammals.  And yes - they can eat other sharks.  Ouch!
  • What age can sharks live to? It varies - most live 20 to 30 years, but the spiny dogfish has the longest lifespan at more than 100 years. Whale sharks  may also live over 100 years
  • How can you tell if a shark is a male or female? The main visible difference is in the Pelvic Fins. Males have a longer, pointy fins on the pelvic fins called claspers.
  • Does anything attack a shark? Yes other sharks and killer whales
  • What is the weirdest type of shark? Hmm. difficult to say, but They have the same design when it comes to the skeleton that is both inside and outside of their body for protection and movement
  • How big is a great white shark? The biggest ones have been about 6 metres (20 ft) in length and 2,268 kilograms (5,000 lb) in weight
  • Is it true that when you turn a lemon shark up-side-down it goes to sleep? Yes, sort of. They go in to a sort of trance, possibly due to the increased pressure on their lungs and breathing apparatus
  • How big can a goblin shark grow to? Goblin sharks can grow to 11 feet (3.3 m) long and weigh 350 lb (159 kg)
  • What is the rarest shark? There are a few - but the mega Mouth shark is one of them
  • How many teeth do sharks have? Lots, because they have lots of row of teeth. In a lifetime, some sharks lose 30,000 or more teeth!
  • Why can't great whites be domesticated but orcas and dolphins can? Scientists think that because sharks are really smart, they find it very stressful being in captivity. They definitely realise they aren’t in the their natural environment any more
  • Can we get Great white Sharks in Scotland? It’s possible that Great white sharks could be "occasional visitors" to the UK and there are reports of one seen off Scotland
  • What's the biggest shark in the world? Some sharks can grow up to to 10 or more
  • How do sharks smell blood underwater? Is it true that sharks have an extra sense? Most of a shark's senses are highly developed and efficient - including a powerful sense of smell
  • Is it true that hammerhead sharks use electricity to find their prey? Yes. Like all sharks, hammerheads have electroreceptory sensory pores in their skin
  • How many sharks live in the waters of Scotland? There are around 18/20 species in the UK
  • Are sharks fins used for soup? Yes, unfortunately, particularly in asian countries where it is considered to be healthy and full of nutrients
  • Why do sharks have to keep moving? Unlike bony fish, sharks do not have gas-filled swim bladders for buoyancy. Instead, sharks rely on a large liver, filled with oil  The liver's effectiveness is limited, so sharks have to work hard to maintain depth, sinking when they stop swimming therefore most sharks need to constantly swim in order to breathe and cannot sleep very long, if at all, without sinking. However, certain shark species, like the nurse shark, are capable of pumping water across their gills, allowing them to rest on the ocean bottom
  • Is it true that if you punch a shark in the mouth that it goes in to a trance? Yes. Some sharks, if punched or stroked on the nose, kind of pass out. Researchers use this condition to handle sharks safely
  • How did Bull Sharks get their name? The name bull shark comes from the shark's stocky shapes, broad, flat snout and aggressive, and unpredictable behaviour


  • Why do some mammals live in the sea? Way back in history in history, there have always been some mammals that lived in the sea.  Some have just developed on from this to being land animals with fur and others haven’t.
  • Why do some animals which live in the sea have scales, while others like sharks don't? Many of the animals in the sea are different species and have developed differently and are water proof in different ways!


  • Do shrimps ever change colour? Only when they're cooked!
  • How are whirlpools are formed? A whirlpool is formed when the normal path of a current is disrupted



Marine Scotland
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Victoria Quay

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