WHAT
ANIMALS
DO
SWIM, FLY, JUMP, ANE RUN
Can fish swim backwards?
Yes, there are several fish species that can swim backward. But most of them are really only drifting with the current.
Butterflyfish belong to the group of fish that actually swim backwards on purpose. It is a group of fish with fat, thin bodies, usually with a line next to the eye and sometimes a dark spot near the tail fin. The pattern works as a camouflage or defense mechanism that confuses predatory fish so that they bite at the wrong end of the prey.
Another fish that can swim backward is the tanganyikacichlid Triglachromis otostigma. It lives in the muddy ground regions of the Tanganyika Lake between Tanzania and Congo and it has developed bendable fin tips on its pectoral fins. By swimming backward, the fish can use its pectoral
fins to dig up insect larvae that are hidden in the mud. The Knifefish, or “Black Ghost,” Apteronotus albifrons , can swim both forward and backward, and even upside down!
Crayfish also swim backward when they are frightened. That they crawl backward, on the other hand, is a myth. We should therefore not say that crayfish can walk backward!
Can bumblebees fly?
That bumblebees cannot fly is an old student myth. According to the myth, bumblebees are too heavy, too round, and equipped with wings far too small to fly. This is of course not true; bumblebees are in fact well equipped to fly.
The rumor of the bumblebee's inability to fly has its own story. It probably originates from a student joke at the Institute of Technology in Stockholm. The mathematical measurements that were published in the student newspaper Brux were made without considering the bumblebee's wing movements. The truth is that bumblebees cannot glide, an characteristic they share with most other insects.
If you remove the thick fur coat, the bumblebee body is quite similar to the regular Western Honey Bee. In some regards the bumblebee's ability to fly can even outperform regular bees; for example, they can fly in winds up to about 9 mph, while honey bees face a problem at only 4 mph.
That bumblebees cannot hear is, on the other hand, completely true, but they do have an excellent sense of smell.
How long can a fly fly?
Generally speaking, insects are sensitive to wind and they try to find more calm places when it is windy. But of course there are differences between different species—there are about 4,500 different kinds of flies in Sweden.
Some horse flies can get up to 1.18 inches long and relatively heavy; they handle wind better than a housefly. But how many miles per hour can they go? That research still remains to be done! However, the On Duty Biologist has done some observations on his own: One summer day when he started his car the side windows were full of flies, probably houseflies. Most of them disappeared quite fast when the car accelerated, but not all of them. The fly that held on the longest was sitting on the left side of the car window and did not give up until the speedometer showed over 43 mph.
BY THE WAY...
In only one second a cockroach can run its own body length times thirty. It usually only runs very short distances, for example to escape the light from a lamp turned on in darkness. But when it runs, it runs fast!
TOP SPEED FOR A FEW COMMON NORDIC ANIMALS
› European Hare 44.7 mph
› Mountain Hare 43.5 mph
› Wolf 37-43.5 mph
› Fox 31-37 mph
› Moose, about 31 mph
› Wild boar, like a moose but short distances
› Roe deer, like a moose
› Brown bear 28 mph
› Badger 15.5-18.6 mph
› Housefly almost 5 mph
How far can a squirrel jump?
. . . a normal sized grasshopper can jump about 10 feet if it stretches out its wings and glides?
. . . grasshoppers normally do not fly? The pink-winged grasshopper, Bryodema tuberculata , is an exception and it can fly hundreds of feet.
. . . Roe deers and hares do not have any collarbones? Animals that run and jump a lot need the most possible mobility in the front legs and because of this the shoulder blades cannot be attached to the rest of the body.
. . . the hedgehog is great at climbing? Hedgehogs have been seen to climb fences over 6.5 feet high!
. . . the Common Swift is the bird that spends the most time in the air? From the day the bird leaves its nest it flies nonstop for about 310, 685 miles until it lands to nest for the first time, two years later.
. . . the Common Swift has such weak legs that it needs help to gain air under its wings if it lands on the ground?
LONGEST AND HIGHEST!
Arctic Terns that nest in the Arctic Ocean and then fly to the other end of the earth to “hibernate” in Antarctica make a journey of about 24,850 miles!
Snow Geese nest on the tundra in Siberia, amongst other places. When they move south some individuals fly over the highest tops of Himalaya, more than 26,246 feet above sea level.
Rüppell's Vultures and Cinereous Vultures are known for flying high. A Rüppell's Vulture probably holds the record for highest flying; a Rüppell's Vulture almost caused a catastrophe as it was caught in a jet engine of an airplane 37,073 feet up in the air.
RECORD-BREAKING EAGLE
Just like other birds, Golden Eagles use a few different methods to fly. When it flies under certain conditions, or rather glides downwards, it can reach a speed of almost 80 mph. A Golden Eagle in Scotland was clocked flying at a speed of 118 mph when bullied by a Peregrine Falcon, but the numbers are uncertain. The average speed for regular horizontal fight varies from about 28 to 31 mph.
LISTEN, MAKE NOISE SEE, AND GLOW
Do grasshoppers have ears on their stomach?
Yes, as a matter of fact they do! Grasshoppers' hearing organs are placed on either side of the first rear body segment, or the “stomach.” Katydids and crickets have their ears placed on either side of the front shin bone, just under the knee.
Most land-dwelling animals that make sounds have ears and can hear well. Well-developed hearing organs can be found on insects that produce sound for their own purposes, for example grasshoppers, katydids, and cicadas.
Many insects react to sound waves without having a specific hearing organ. Especially low tones can create vibrations in solid objects, for example an insect body. The vibrations are perceived through sensory cells that can be found in Johnston's organ. This organ is placed in the antennae, and it is formed to a greater or lesser degree depending on the insect. The Chironomidaes and the mosquitoes have the most well developed Johnston's organ.
BUZZ, RUSTLE, SNAP
Insects buzz, rustle, snap, and make other sounds in different ways. In most cases the sound is a side effect that has no distinct purpose, sort of like the sound from an engine. However, some insects consciously produce sound to communicate. It can be used as a means of contact between sexes, like for example with grasshoppers and katydids, or with miscellaneous individuals as is the case with social insects like wasps and bees. In a few cases it is believed that the sound has a frightening effect, for example the Death's-head Hawkmoth's squeaking, chirping sound or the Apollo butterfy's rattling when you get too close to them.
A common way for insects to communicate is to rub two body parts against each other. One body part that is equipped with a row of small teeth, the so-called file or bow, is rubbed against a raised segment on another body part and it creates vibrations, the same way as when you pull your nails over a comb. On grasshoppers it is the thighs that act as bows and they are rubbed fast against a raised segment on the narrow and hard forewings. On katydids it is the left wing base that is the bow, and it is rubbed against the right wing base that has a rasp next to a crystal-clear membrane, the mirror. When the katydid wants to play it lifts its wings and moves them sideways so the bow is touching the rasp and the membrane starts swinging very fast.
GRASSHOPPER OR KATYDID?
Grasshoppers have short antennae, while katydids have very long antennae and are also usually bigger than grasshoppers.
. . . a normal dog can perceive very high tones of up to 100,000 Hz? That is about five times higher than what a human can hear. They also have a better ability to sense lower frequencies.
. . . some wolf spider males court their females by drumming their abdomen against a surface? The females do not have any ears, but they can feel the vibrations.
. . . Fieldfares can hear the worms under the ground? To be able to better locate where the worm is digging through the soil they angle their head and ears toward the ground. Many people might believe that it is pure luck when the Fieldfares peck their beaks into the ground and pull up a long worm. But it's not the case!
. . . scared grass snakes smell bad? A frightened or excited grass snake can secrete smell through the skin and, if threatened, will empty the anal glands and cloaca of its stinky contents.
. . . that owls see with their ears when it is dark (but use their eyes when it is light enough)? Each opening for the ear has a different size and they are also somewhat different in height relative to each other. The ears are specially adapted to locate prey in three ways: in distance, sideways, and in height.
Why does the cat purr?
The cat does not only purr or spin to express that it is enjoying itself and feels well. It also purrs when it is frightened or worried, sometimes even when it is about to die and this is probably to calm itself. A new theory suggests that purring may have a healing and strengthening effect on the bones, by stimulating bone cells through the vibrations of their purring.
Animals that purr belong to the family of cats, Felidae, with its 42 species and the Viverridae, with its 66 species including the subfamily Paradoxurus, Paradoxurinae. But not all cats spin; the big cats—lion, tiger, leopard, jaguar, Snow leopard, Clouded leopard, and Neofelis diardi-do not spin. The puma is by definition a big cat and it can spin, but it is more closely related to the small cats than the big ones. The Eurasian lynx can also spin.
There are many theories about how the spinning or purring happens, and we do not know for sure how the cats are doing it. Probably the phenomenon is connected to the hyoid bone that can be found in the throat of small cats. Big cats have an elastic ligament instead of a bone.
BIRDS DO NOT HAVE ANY VOCAL CORDS
Birds do have a larynx but since it lacks vocal cords, the larynx cannot make any sound. The sounds are instead produced by syrinx , an enlargement of the larynx right where it splits into the two main bronchi, down in the chest cavity.
The syrinx has muscles and connective tissue made up of cartilage, and one or more vibration membranes that contribute to the production of sound. The cartilage is more or less converted fibrosis that is equivalent to the supportive fibrosis found in the larynx in mammals. Many birds have poorly developed syrinx muscles, for example storks, which explains why they are known for communicating by clattering with their beaks. Passerines, on the other hand, have a very well developed syrinx. Amongst these birds we can find many famous singing birds, like the Nightingale, Common Blackbird, and the Canary.
Since the syrinx is located below the larynx it is a part of the sound-producing apparatus, sort of like the pipe in a wind instrument. Because some birds have a substantially extended larynx and can make one or more notes, the similarity to a wind instrument then becomes even more striking. A long larynx allows the bird to produce lower tones. For example, the larynx of the Common Crane creates a double loop connected to the keel.
LATE SUMMER SINGING
After midsummer, birds usually become considerably quieter. It is because the struggle for females and the best territories is over, and the birds now have families. But it is not completely silent. There is still singing to be enjoyed from an occasional Chaffinch, Willow Warbler, Common Wood Pigeon, Blackcap, Eurasian Wren, or Blackbird. The birds singing at this time are partly males that did not succeed in mating yet, and partly males that want to start a second or third mating cycle.
Can moose see colors?
Moose, just like other species in the Cervidae family, are almost completely lacking the sensory cells, called cones, in the retina of the eye, which are essential for color vision. Moose are therefore almost entirely colorblind.
We can assume that moose experience their surroundings on a gray scale. Moose are, however, very good at detecting movement. The same goes for hedgehogs, which by the way have terrible vision. They can recognize contrasts of light against dark, but not objects. Although the hedgehog has poor vision, its sense of smell is excellent, and it is phenomenal at recognizing all sorts of smells. Its hearing is also very impressive.
Mammals' color vision is fairly well explored, but our knowledge of insect vision is minimal. Most of our facts are acquired from studies on the Western honey bee, and this knowledge has been transferred to other insects. It is well known that butterfflies do not perceive colors the way we do. They also see colors that we cannot see, like ultraviolet light. Plants with nectar usually have bright colors and an entrance for insects in ultraviolet-colored patterns, to make themselves more attractive to nectar-eating insects.
LATE NIGHTERS ARE ATTRACTED TO LIGHT
Moths and other insects that are active at night are good at navigating by the starry night sky. But they are also attracted to the artificial light that humans invented. The dilemma here is that the sources of light created by humans are not infinitely far away, like the stars, but on the contrary within reach. When they get close to the actual source of light they become confused, maybe even blind, and do not know what to do. That is probably why they can be seen circling repeatedly around outdoor lights.
Examples of insects that are active at night and attracted to light are moths, caddies flies, chironomids, and other mosquitoes, some parasitoid wasps, European hornets, and some beetles. There are also birds that are attracted to light, for example Water Rail.
That bats are attracted to the color white is an old myth. Maybe the light surface attracts insects and thus also hungry bats. Or perhaps bats are just more easy to spot against a light background.
SOME OF THE MOST SENSITIVE ANIMALS
Bats have the best hearing and can also sense sounds that we cannot hear.
The Lobster Moth males, belonging to the family Notodontidae, have the best sense of smell. Male moths can smell a female moth several miles away.
Fish have the best sense of taste-they can actually find their way home by tasting the water. Imagine, eels might even feel the taste of their traditional mating place far away in the Sargasso Sea!
Birds of prey have the best vision. The Golden Eagle is said to be able to spot a hare from 9,840 feet. A Peregrine Falcon can see a dove from a distance of almost 5 miles.
Do self illuminating insects really exist?
Two species of insects that are self illuminating are the common glow-worm and the lesser glow-worm. Both are beetles, and the common glow-worm is (surprise!) more common.
It is in particular the female glow-worm that glows. She looks like a 1.1 inch-long gray-brown insect larva, but on the last two segments on the bottom of her abdomen there is a yellow colored area that light shines from. Usually the female is sitting still on a leaf a little bit above ground level and turns the tip of her abdomen so that the light is not blocked by the leaf. The light is yellow-green, similar to the type of light that burning phosphoric gives of. It is produced when the substance luciferin reacts with an enzyme causing it to oxidize to oxyluciferin. Almost all of the chemical energy is transformed into light, only about five percent is turned into heat.
The glow-worm male has wings and very large eyes. As a full-grown beetle he is about 0.5 inches long, with grey-brown elytra and a grey-yellow prothorax. He only glows weakly.
THE EUROPEAN ROBIN HAS MAGNETIC VISION
European Robins notice when the days get shorter and it is time to migrate. While moving south, they know how far they have gone by feeling the variations in the earth's magnetic fields. Now we also know that the magnetic field can affect the nutritional intake of birds. If you let the European Robin experience a magnetic field comparable to the one in the south of Spain, they will not gain the extra layer of fat that is needed for the long journey because the birds think they have already reached their destination. It is still unknown how the European Robin can feel the variations in the magnetic fields on earth.
SPEAKING OF . . .
How many degrees can an owl turn its head in each direction? 135° in each direction-in total three-quarters of one turn, 270°.
A PERSPECTIVE ON EGGS
Does the egg come out with the pointy or round end first?
The last part of the female bird's oviducts are rich in mucous glands; the secretions from these glands faciliThate the egg's passage out of the body. This usually happens with the round end first, but not always. Penguin's eggs always come out with the pointy end first!
Different species's eggs look a little different. Over the course of evolutionary change, they have formed partly to come out of the body as painless as possible, and partly to be easy to hatch. Most eggs are more or less round, since it is likely the most practical shape. The Common Murre's eggs are sometimes left unattended on a narrow ledge, and since the egg is unevenly elongated it spins around its own axis when it lays by itself and cannot fall down from the narrow ledge.
Light, single-colored eggs are usually hidden in dark hollows. Species that lay their eggs in more visible areas often have speckled eggs, so that the eggs blend into the surroundings when the hatching bird leaves the nest. The unhatched eggs are safely camouflaged.
THE CHICK BREATHES THROUGH THE SHELL
The nutrition that the chick needs can be found inside of the egg but oxygen is taken up through pores in the shell. A regular egg from a hen contains nearly 10,000 of those pores. Trough these microscopic “holes,” oxygen comes in and carbon dioxide and water vapor go out. The chick is still not breathing with lungs, but receives oxygen through the fetal membranes, called the allantois. Blood from the fetus is circulating out to the allantois, where they takes up oxygen and lets out carbon dioxide.
At the pointy end of the egg is an air chamber between the two shell membranes. This chamber increases in size as water vapor from the growing chick evaporates from the egg. When the time for hatching is approaching, the chick pecks a hole in the air chamber and when it breathes in the air the lungs start working; at the same time it continues to receive oxygen through allantois. When it has finished pecking itself out of the egg shell, the baby bird begins to breathe using just its lungs.
REPTILES CANNOT HATCH
Birds and reptiles such as crocodiles and turtles are very closely related, and have similar eggs: The exchange of oxygen and carbon dioxide takes place in almost the same way. The major difference in the construction of the eggs is that reptiles do not have an air chamber. Another difference is how the eggs are kept warm: Since reptiles lack body heat of their own they have to rely on the sun to hatch their eggs, while the warm-blooded birds hatch without the same level of external heat.
Amphibians, on the other hand, lack fetal membranes in their eggs, which therefore have to be hatched in moist environments where the eggs can take up oxygen from the water. A few lizards, such as the Chalcides in Southern Europe and North Africa, have taken care of the fetuses' need for oxygen in an advanced way: Their fetuses are carried in the oviducts and receive oxygen through a variant of placenta that resembles the one that mammals have.
. . . the world's largest egg was laid by an ostrich in Borlänge? It weighed 5.5 pounds, which is equivalent to about 42 normal sized hen eggs.
. . . the world's smallest egg was laid by a hummingbird? It was less than 0.4 inches long and only weighed 0.014 ounces.
. . . spiders spin small silk sacs for their eggs? Some spiders leave the eggs to their fate, others carry around the sac until the eggs hatch. Other species then carry around the newly hatched babies until they are big enough to manage on their own, but in some cases the babies end up eating their mother.
. . . the Humpback whale lays five to seven eggs? However it is unusual that as many as five babies survive until the winter comes.
. . . Grass Snakes lay eggs once a year and it happens sometime between June and September? It then takes 5-10 weeks for the eggs to hatch.
. . . big eggs often have thinner shells than small eggs? That is because all egg shells contain almost the same amount of calcium, no matter what size they are. Usually young hens lay smaller eggs with thicker shells than the older hens do.
How do female birds produce enough lime to form a shell on the eggs?
Domesticated hens are often provided with supplementary lime, and we can assume that wild birds are skilled at finding sources of lime in nature. For example, female birds eat shells from snails but they have to be eaten at the right time, preferably on the night before the egg is about the be laid.
In the spring, you can provide birds with lime by laying out the shells from your breakfast eggs on the lawn! Blue Tits, Great Tits, Magpies, and other species will eat with great appetite. Birds can also keep extra supplies of calcium in their body in cavities in their skeleton. These extra supplies can then be released and used for producing eggshells.
D-hormone (vitamin D) has an important function in the birds' production of shells. Among other things, it is necessary for the ability to take up calcium from the intestines, and so that calcium can be released from the extra supplies in the skeleton. D-hormone exists in the body but it needs UV light from the sun to transform into the active form. It has been well known for a long time that birds in tropical areas (with shorter days) lay less eggs than birds in temperate regions (with longer days). To lay from 8 up to 16 eggs like our Great Tits would be nearly impossible in the tropics!
THE DOMESTIC HEN LAYS THE MOST EGGS
In nature birds usually lay eggs during a limited period of time, often in the spring, and then start hatching when the nest is full. But if the eggs are removed, the hen continues to lay. With domestic hens this behavior has been refined through breeding so that hens nowadays can lay one egg every day—all year round. But optimal nutrition and environment is necessary—the right light, temperature, and humidity—in order for it to work. With increased ability to lay eggs, the will to hatch is less, which means that commercial hens rarely manage to hatch chickens—if they get the chance to.
A LIVING PANTRY FOR THE BABIES
Mellinus arvensis is a wasp-like Sphecidae that is very common. When the female lays her eggs she first digs a pipeline cavity in the ground, 11-15 inches deep. Ten she takes of hunting. She sneaks up to a fly or any other suitable prey and paralyzes it with her poison. When the fly has been subdued, she flies it to her cavity in the ground and pulls it down. The fly, still alive, is placed in a so called cell, and a fertilized egg is layered on top. Ten she seals the cell and takes of hunting again. She continues this way until she has laid about 15 to 20 eggs in as many cells and the cavity is filled. As the eggs hatch the larvae eat their flies, and pupate over the winter. The year after, the new Sphecidaes are hatched.
ANIMALS THAT LAY EGGS AND
HAVE AN INTERNAL FERTILIZATION SYSTEM
› All birds
› All insects, i.e. beetles, butterflies, flies, etc.
› All molluscs, i.e. snails, clams, octopuses, etc.
› Many reptiles, for example crocodiles, turtles, and snakes, but not the common European viper.
› All spiders and ticks.
› A few fish, for example sharks and rays.
› Tree species of mammals: platypus and two spiny anteaters.
Maybe a few arthropods also have internal fertilization, since they mate, but it seems as if the fertilization itself takes place outside of the female body. The sperm is transferred through fluid or in the shape of so called spermatophore to the female, who keeps the semen in a capsule for some period of time; it,s her decision when the eggs are going to be fertilized. The eggs are then hatched either as juveniles, which resemble the grown arthropod, or as larvae which pass through several different stages before it reaches adulthood.
A QUESTION OF AGE
Which animal lives the longest?
There are few facts about animals' maximum ages, and they are usually based on the lifespan of animals that lived in zoos. In nature, animals rarely become as old since they more often surrender to predatory animals, starvation, parasites or illness.
Amongst mammals, human beings live the longest with a maximum lifespan of 110 to 120 years. Apes do not become as old; the chimpanzee is said to live up to 40 or 50 years, and the gorilla about 50 years.
Generally mammals live longer the bigger they are. Humans are not typical since we live a very long time, relative to our bodyweight. The Indian Elephant is said to live up to 70 or 80 years in nature. The African Bush Elephant can get up to 60 years old, and the African Forest Elephant lives up to 80 years. There are no secure data about the big whales, but according to certain estimates they can live for more than 100 years. If this is true, there are many species of whale that compete with humans for being the mammal that lives the longest.
THE EYE CAN TELL
The accounts of having found harpoon blades of stone and ivory in today's Bowhead whales appears to be rather unbelievable. The Inuits stopped using that type of harpoon in the middle of the 1800s, which would have made these whales a lot more than 100 years old. The discovery of harpoons sparked scientists to try to determine the age of Bowhead whales by using age-related changes in the proteins that build the lens of the eye. Unlike most other proteins in the body these can not regenerate; the proteins the furthest back in the lens can thus be dated from when they were first formed in the fetus. When the eye lenses of a number of Bowhead whales killed within the years of 1978 and 1996 were studied, five whales were found to be older than 100 when they died. One of the whales was determined to be 211 years old, and could thereby be the oldest known mammal. If we look at vertebrates, there are big tortoises that can live up to 150-200 years. From India there are accounts of a turtle that was captured in the Seychelles and lived for 255 years before it died in captivity. The most famous of all turtles, Lonesome George on the Galapagos Islands, however, only had an estimated age of 70-80 years. The gloomy name comes from being the last individual of his subspecies.
SOME LIVE FOREVER
How long does a butterfly live?
The answer depends on how you count. The life of a butterfly starts with the egg and continues with a number of caterpillar stages and then on to the pupa stage, and finally reaches the end-stage, the full-grown butterfly. If you count that way most butterflies live for about one year.
Some butterfly species have time for several generations during one season and then live a considerably shorter life. That goes for the Macroglossum stellatarum that we can see when autumn comes and that probably are hatched from eggs of butterflies that came here from the Mediterranean in June-July. They die the very same autumn and have a lifespan of only two months in total.
It should also be mentioned that several species have a lifespan of two years or longer, for example many species that live a harsh and difficult life on moors or similar places. Some species can live as a pupa for a very long time, the Small Eggar for up to nine years!
LIFE CYCLE OF THE SMALL TORTOISESHELL
The Small Tortoiseshell belongs to one of the species that hibernates as a full-grown butterfly. When the overwintering area is warming up in the spring, hibernation is interrupted and the butterflies start looking for a suitable partner. After mating, the female lays her eggs on young nettles. The eggs are hatched after a week and the larvae eat the nettles. The larval development that takes place before pupating lasts for two to three weeks, and the pupa stage then lasts for one up to two weeks. The full-grown butterflies are hatched at the end of June and all the way into August.
Newly born butterflies quickly find flowers rich in nectar and there they fuel themselves for a couple of weeks. After that they go back to their overwintering areas, a cavity in a tree or the ground, an outdoor basement, or simply on a tree or a branch. They do this whether or not it is cold or it stays warm outside. Here they settle down to rest with their wings folded together in an upside-down position until next spring.
HOW LONG IS THE LIFESPAN OF . . .
. . . a wolverine?
In captivity it can live for 16-18 years but there is no proof of how old it can get in its wild habiThat.
. . . a salmon?
The data varies from 13 to 15 years.
. . . a woodpecker?
The highest known age for a Great Spotted Woodpecker is 12 years and 8 months.
. . . an earthworm?
Since earthworms live under the ground they are very difficult to study. According to reports our common earthworm, Lumbricus terrestris , lives 5-6 years.
. . . a bat?
If the bat survives its first winter it can live up to 20-30 years old. However a great number of the babies, more than half, die during their first year of life.
. . . a tick?
A normal female tick lives between 2 and 6 years.
. . . a hedgehog?
Up to 19 years.
. . . a cat?
According to The Guinness Book of World Records, a
domesticated cat can live up to 34 years.
Putte from Helsingborg is the longest living eel that has been documented. He was captured in 1836 and at that point had an estimated age of three years. He was kept in captivity at the Helsingborg museum until he died in 1948, at 88 years old. In a wild habiThat eels are said to live for 50-55 years. There are also a great deal of unconfirmed rumors with unknown accuracy. One stubborn rumor was circulating in the media at the beginning of the 1960s, of an eel in a well in the Scanian Brantevik that was said to have lived for 103 years.
FOOD AND DRINKS
How many cones does a squirrel peel and eat in one day?
The squirrel has a built-in “nutcracker” in the form of teeth made for gnawing that constantly grow. It can open cones by quickly chopping of every cone leaf and then catching the two seeds found next to it.
To eat a spruce cone takes an average of seven minutes for the squirrel, while a pine cone can be eaten in only three minutes. But how many cones a squirrel can eat is more diffcult to know. Squirrels at a research center ate seeds from about 30 spruce cones each day, even if the variation was great. Many factors affect the intake of cones; for example, squirrels eat less if it is windy, rainy, or cold and snowy. Squirrels strongly dislike cones that are sticky with resin, so if they find many they'll seek out another tree with less sticky cones.
If you are in the woods and are watching a squirrel peel cones, it may happen that the squirrel starts swishing its tail back and forth, smacking its paws together, and jumping so that its claws make noise against the tree bark (it can be heard from a distance of several hundred feet in a quiet forest). This is the way squirrels communicate to other squirrels that there is danger nearby. Maybe it saw you and was frightened and thought you were disrupting, or it saw something else it considered as a threat. For example a Northern Goshawk, a hawk that likes to eat squirrels. If the squirrel manages to see the hawk before it sees the squirrel, it stays very quiet and freezes to stay undiscovered. Generally it sits that way for up to ten minutes before it becomes active again.
. . . the most important food for the squirrel during autumn and winter are seeds from spruce and pine cones, as well as hazelnuts when they can be found. Spruce and pine cones are very rich in protein and fats, and also contain several important minerals.
Do fish drink water?
The question can be answered in a few different ways depending on the fsh's environment. The fish adapt in different ways depending on whether they live in freshwater, salt water, or brackish water.
“Simple” fish like the Atlantic Hagfish have a similar concentration of salt in their bodily fluids, as the surrounding water. Sharks and rays, on the other hand, have a lower concentration compared to the surrounding water. Their method to even out the concentration of salt in their body is complicated. The method does however not necessiThate that the fish drink; it is an internal regulation.
Freshwater bony fish, for example perch or pike, have a higher concentration of salt in their bodily fluids compared to the surrounding water. The result is that water is constantly going in through the skin and the gills. Consequently they continuously have to get rid of water and they do this through highly effective kidneys that produce diluted urine. They also lose water through the gill membranes.
COD AND MACKEREL ARE DOING IT!
Salt water bone fish like cod and mackerel have a salinity level that is lower than the surrounding water. Therefore they tend to lose water through the skin and gills, and they must replace the water that has been lost at the same speed. Therefore they have developed mechanisms and behavior to compensate for the loss of water; for example, their kidneys are specially modified. Drinking alone would not be enough. The intake of water is aided by specialized stages in the digestive system.
Why do butterflies not burn on nettles?
The Small Tortoiseshell is one of our most common butterflies. It lays its eggs on our nettles and the larvae that are born live of nettles. But why don't they get burned?
The stinging hairs on nettles are hollow and connected to a small sac of venom. The hairs are very fragile and break even at the slightest touch. Their tip then breaks at an angle and operates as a thin needle when the venom sac is emptied. How the Tortoiseshell larvae manage to not break the stinging hairs and be hurt by the sharp edges is still a mystery. One possibility is that they are immune to the poison, but it seems more likely that they somehow manage to not break the stinging hairs.
The nettles' equal among animals, the jellyfish, does not have many enemies. However there is one fish that does not hesiThate in front of the burning jellyfish tentacles— the lumpsucker. It eats not only jellyfish, but also small arthropods, polychaetes, and small fish.
POISONOUS NECTAR
It is worse for bumblebees that eat poisonous nectar. Every year, especially around midsummer, dead or dying bumblebees and bees are found on the ground under linden trees. The cause of this is not confirmed. According to some scientists, the insects die from natural toxins in the pollen of the linden tree called saponins, which dissolve red blood cells. Other scientists believe the nectar of some linden trees contains the sugar mannose that bees and bumblebees cannot digest. They then die from starvation even though they are full of food. Why some linden trees produce mannose is unknown. Another, but maybe not very likely, theory is that a process in the bee's intestine transforms linden nectar to a poisonous substance.
SPEAKING OF
Insects can never grow fat because they have an outer skeleton made from hard chitin, the shape of which does not change. Insect larvae, on the other hand, can become rather fat. The abdomen can get enormously swollen, not because they are fat, but because the females carries the eggs.
How does the spider's digestive system work?
The digestive process of spiders takes place both internally and externally. The spider injects its poison in the prey through canals in their jaws. The poison is usually adapted to what prey the spider has caught, and if it is supposed to kill or paralyze the prey.
The poison starts the process of breaking down the prey to liquid, because spiders can only eat fluids. Ten the spider sucks up the melted guts. During the meal the prey is usually in a cocoon.
Despite its poison, spiders are mostly known for the noble art of spinning webs. All spiders can spin, but not all can make webs. The family of orb-weavers, to which the European Garden Spider, Araneus diadematus, belongs, spins the characteristic and most well recognized wheellike net. The sticky threads of the catch and hold flying prey for a while until the garden spider, who often is waiting in a spun hiding place at the edge of the net, registers the kicking catch through vibrations in the thread. The spider then quickly rushes over, spins a cocoon around the prey, and kills it or paralyzes it with its poison. The web has both sticky and dry threads, which allow the spider to walk only on the dry threads and not get stuck like his prey.
Similar webs for catching prey are made by a large number of spider species. Usually the net is constructed so that you, with some practice, can learn to see what species made the web.
Where do fruit flies come from?
We have all experienced how fruit flies pop up from nowhere. They gather in leftovers of apples, fruit peels, and overripe fruit to eat and reproduce.
If the weather is warm and you happen to have left overripe fruit in the kitchen, it easily attracts fruit flies and other small flies that are dependent on fruit. The females lay their eggs in the pulp, where there is no risk of them drying out. But there is not much oxygen; the egg, which is about 0.02 inches long, therefore has two outgrowths for breathing—“gills”—that stick out into the air and help it to absorb oxygen. Soon the egg hatches into a little larva that starts to eat the pulp. When it has grown for a few days, it becomes an immobilized pupa. After another few days, a full-grown fruit fly is hatched from the pupa. Since all the stages from mating to becoming a sexually mature fly only take about ten days in optimal conditions, the fruit flies can multiply rapidly.
The small fruit flies are most common in the summer but can also show up other times of the year in fruit that we carry home from the grocery store. The risk is particularly big with unconventional fruit. The fruit fly larvae can also live in fluids like wine and beer. The pupation then takes place on the inside of the container, above the liquid surface. If you leave wine in open containers to make vinegar you can be sure to attract these flies. That is why they sometimes are called vinegar flies.
HOW TO GET RID OF THE FLIES
Mix one part water, one part apple cider vinegar, and a few drops of dishwashing liquid (to remove the surface tension) in a glass and place it on the sink. In a few days the fruit flies will have gathered in the glass and you do not have to deal with them buzzing around you!
. . . the fruit fly is one of the best animals for geneticists to experiment on? The reason is partly that the flies have such a short generation time, and partly because the salivary glands in full-grown larvae have so-called giant chromosomes that are easy to study.
HUNTING BEHAVIOUR OF . . .
. . . antlions?
Antlions are predators that live in sand. They throw away the sand so that a funnel-shaped pitfall is created and then stay at the bottom waiting for ants and other small insects to fall down. The antlions use their powerful and hollow jaws to hold and drain their victims.
. . . Common Buzzard?
Common Buzzards do eat snakes, but their most common prey is voles and mice. They have three different ways of hunting: the most common is to sit on a lookout, for example on telephone poles, dead trees, or high rocks. From there they dive towards their prey.
In other cases they glide about 320 feet over open terrain and dive on their prey when they have discovered it. Often they have to continue to hunt the prey for a while on the ground.
WHAT IS THE DIET OF . . .
. . . Roe deer?
Roe deer are real connoisseurs and carefully select their food. They have to pick high quality food at the right time of the year. They need to be so careful because roe deer cannot handle food with too much fiber in it. The food has to be easy to digest and full of nutrition. It is best that they eat berry bushes, for example blueberry and lingonberry, but heather as well. Since the range of plants varies during the year, their diet differs depending on season. In the spring the first growing straws of grass are very popular, and the so called garden Roe deer are very fond of allioideae, a subfamily of flowering plants. In the summer, the Roe deer eat a lot of herbs and leaves, and in the autumn they prefer mushrooms when they are available, otherwise berry bushes. Ripe oats and wheat can be tempting too, but not rye or barley! In the winter the berry bushes are important, but if the snow is covering the ground they eat a great deal of needles mostly from pine, but sometimes spruce, which they don't like as much.
. . . pikes?
Pikes eat most things that pass by, including ducklings, frogs, snakes, and crayfish. The latter are their favorite, and the hard shell is not a problem for the pike to digest. There are reports of a pike caught recently that had three large crayfish, each about 2.7 inches long, in its stomach!
. . . butterflies?
Most common with grown butterflies is that they suck or drink a sugary solution (nectar) from flowers but some of them do not eat at all. Butterfly larvae mostly eat different parts of plants.
. . . ladybugs?
The majority of ladybugs are predators, both as larvae and as full-grown beetles. They mostly eat plant lice and scale insects, but sometimes they can be seen drinking the nectar from a flower.
. . . ground beetles?
Both larvae and full-grown insects are mainly predators that are very active in their hunt for prey, for example earthworms, insects, or small snails.
. . . grasshoppers?
Grasshoppers mainly eat grass, and the same goes for katydids who also eat seeds and different small animals.
WHY ARE BIRD DROPPING WHITE?
Birds have a single body orifice for feces and urine as well as reproductive waste, called a cloaca. The urine gathers in the cloaca where the fluids are absorbed back into the blood. The final product is then a semi solid light mass of uric acid—bird droppings.
No, flies do not “taste” food when they rub one leg against the other. Just like us, they have their gusThatory system in the mouth. They are most likely cleaning themselves and rubbing of little particles that stick to their legs and wings. To be able to fly as fast as possible it is important to keep weight down.
WINTER—SLEEP AND COLD
Do flys sleep even though they don't have any eyelids?
No, flies do not sleep. They do lack eyelids, but that is not the reason why they do not sleep. Just like humans need sleep, the flies need inactive periods; they then sit completely still and try not to be seen.
Sleep is a recurring, spontaneous sThate with impaired ability to react to outer stimuli. In other words it is a form of rest. All higher animals down to reptiles, as well as a few fish species, sleep regularly.
Hibernation is a special type of sleep. Hibernation is a sThate of inactivity during a long period of time, usually with reduced life functions. During hibernation body temperature drops close to the temperature of the surrounding climate.
As a result, the animal's metabolism is considerably reduced and the body's need for energy is much less. Hibernation therefore saves energy—it is cheap to hibernate and live sparingly on the fat stored from a period of good food supplies. Real hibernation occurs with big and medium sized animals.
THE HEDGEHOG ALMOST QUITS BREATHING
In order for the hedgehog to make it through winter it has to lower its body temperature and thus reduce its metabolic rate considerably. It hibernates rolled up in a special den for the winter, under a pile of leaves or dug down in a compost pile of dirt, or similar places.
The body temperature sinks low (37-42°F) and breathing is reduced from the summer's 40-50 breaths per minute to as few as 6-9 per minute. The heart rate is also dramatically reduced. This conservation of energy makes it possible for the hedgehog to manage six months of hibernation without eating.
Do bears pee in their dens?
No, bears do not need to pee when they are hibernating. If they did they would have a problem with the balance of fluids in their body, since bears neither drink or eat during hibernation.
The only water that bears lose in hibernation is the air that they breath out. But it is replaced with water that is produced when fat decomposes through the process of burning fat, and that keeps the bear from being thirsty. Under nor ma l circumstances when the bear is not hibernating, uric acid and other harmful nitrogen compounds are produced in the body and then released through pee. When the bear is hibernating the nitrogen compounds are absorbed into the blood where they are broken down by bacteria and therefore are not necessary to pee out. During the winter rest, other important bodily functions stop—the bear neither eats, drinks, or poops.
THE BEAR IS ONLY SLEEPING
The bear's winter rest is not a real hibernation, since it only lowers its body temperature by a few degrees. If the bear lowered its body temperature as much as, for example, the hedgehog, it would save a lot of energy and thus not need to “fatten up” as much before winter rest.
So why don't bears hibernate? The answer is that the heating time after the hibernation would be too long. It would take about one day to heat the big body from 41°F to 98.6°F and the process would use up a lot of energy.
It is not only bears that rest in the wintertime. Bats hibernate, since there is no food for them. When nights in the autumn start getting cold, they seek out their hibernation spots. During hibernation, the body temperature drops to the same as the surrounding temperature and the bodily functions run on low energy. Bats can wake up a few times during the winter, to change position or drink water. But they cannot wake too often since it drains the animal's fat reserves. A sleeping bat should therefore not be disturbed during wintertime.
Badgers also sleep through the winter.
BATS REST UPSIDE DOWN
When landing, many bats turn their head downwards when already in the air, so that they can comfortably attach their bottom feet in a resting position. Hanging upside down is the most common way to sleep but not the only one. Some individuals can sometimes be found sleeping horizontally; for example, in the crack of a rock. The reason that they mostly hang is probably because they have a hard time lifting of from a fat surface when they are about to fly of. To hang upside-down makes it easier to just let go and start flying immediately. Their way of hanging so closely together is likely due to lack of space.
What about fish in the wintertime?
When the water temperature sinks, the fsh's body temperature sinks as well since they are cold blooded. Their metabolic rate runs on low speed, since they do not use a lot of energy and thus do not need to eat as often. But as all ice fishermen know, the perch bites also in the wintertime!
Fish are not likely to get cold. Even if they can feel diferences in temperature, the cooling process is so slow that they probably do not even notice it. Since they are cold blooded their body temperature adapts to the surrounding temperature. Most fish however have a temperature minimum; some tropical species die at 59°F. The most extreme fish can stand 28°F (!) and lives in the Antarctic.
Considering how common a material water is, it has many unusual characteristics. One of them is that water is the heaviest at 39.2°F, which means that warmer as well as colder water floats on top. Another unusual characteristic is that ice also floats. That is why lakes and other water currents deeper than 3 to 6.5 feet normally do not freeze at the bottom. If they did, there are many species that would die because of lack of oxygen. A strange exception is the crucian carp who can live even in frozen water in the wintertime.
THE SLEEPIEST ANIMALS
1. The koala: 22 hours per day. It can be compared to a newborn baby, who sleeps about 16 hours.
2. Sloths: 20 hours.
3. Armadillos and opossums: 19 hours.
4. Lemur: 16 hours.
5. Hamster and squirrel: 14 hours.
. . . whales sleep in two different ways? Either they rest calmly in a horizontal or vertical position in the water, or they sleep slowly swimming next to another whale.
. . . dolphins only sleep with one brain half at a time? In this sThate they are less receptive of their surroundings and often only swim in circles.
. . . one of the major unsolved mysteries of science is sleep? We have to sleep but nobody knows why. Humans are not the only creatures that sleep; animals all the way down to at least flies also need to sleep.
BIRDS DO NOT GET COLD
Birds have veins deep inside their legs that work as heaters and prevent loss of heat through the feet. That way they can stand still on ice without being cold. When the temperature sinks under about 14°F you can see how they lower their whole body over the feet, which also helps with staying warm.
INSECTS CAN WAKE UP
Most insects rest as pupae in the wintertime, but there are also those who rest as full grown insects. As soon as the weather starts getting milder and the temperature reaches 30°F, these can wake up from their winter rest. Some are specially adapted to a colder climate, for example winter crane flies.
Amongst butterflies there are a few species that rest like larvae in the winter, usually hairy ones. But even these can wake up in temporary mild weather and crawl of on the snow. The unmistakable fox moth, hairy and brown and up to about 4 inches long, survives even if it is frozen inside the snow or ice!
IF YOU FIND A BUTTERFLY IN THE WINTER
The peacock butterfly, like some other butterflies adapted to winter resting as a full-grown butterfly. If you find a butterfly awake in the winter you can try to put it in a dark and cool place, which gives it a great chance of surviving until it is time for it to be outside and fly. You should not give it anything to “eat.”
Are there butterflies that migrate?
Birds' habit of migrating is a well known phenomena. When cold weather strikes in the autumn they fly south. Ten they return the next spring or summer to nest, since there is more food and space around here. But what about butterflies?
The fact that insects also migrate might not be very well known. The Red Admiral, for example, leaves the heat in North Africa in the spring or early summer and flies up to more northern latitudes. This migration might be because there are too many individuals of the same species or that the food supplies for the larvae is not enough, and so some of them—sometimes all of them—are forced to migrate.
The Admiral Butterfly usually comes here in June. The female lays egg on nettles, the larvae hatch and live of of the nettle leaves until it is time to pupate. The new butterfies are then hatched during the summer. When the days get shorter we can notice a certain pattern of butterflies moving south. That means it is not the migrated individuals that move south, but the next generation.