Sharks don't have swimbladders. Their bouyancy comes from oil stored in their liver and their cartilage, which has half the density of bone.
The name "millipede" literally means thousand-foot, but known species have at most 750. Most millipedes have 36 to 400 legs.
Pill bugs, such as Armadillidium vulgare, are not insects- they are isopods, an order of crustaceans.
Japanese spider crabs have a leg span of up to 12.5 feet and can weigh up to 44lbs. They are described as having a gentle disposition.
While their diet is composed of 99% bamboo, wild giant pandas have been known to eat other grasses, wild tubers, birds, rodents or carrion.
Orca whales have been known to fight sharks by holding them upside down, inducing tonic immobility and in some cases suffocation.
Border Collies are often cited as the most intelligent dog breed. In January 2011, a Border Collie was reported to have learned 1,022 words and acts consequently to human citation of those words.
The giant panda's paw has five fingers and an additional "thumb" formed from a modified sesamoid bone.
About 1 in 500 male narwhals grows two tusks. Only 15 percent of female narwhals grow tusks at all, and there is only one recorded case of a female with two tusks.
Some species of starfish start life as males and become females as they mature. In Nepanthia belcheri, a large female can split in half, resulting in two males.
Sloth fur grows away from the extremities to provide protection from the elements while hanging upside down. It is often colonized by symbiotic cyanobacteria which provide camoflage.
Anteaters are toothless and digest their prey using a modified gizzard-like stomach, aided by ingested sand and dirt. They also do not produce stomach acid, instead using the formic acid in their prey.
The Textile Cone sea snail has a shell which grows in a pattern resembling that of the rule 30 cellular automaton. The similar rule 110 is turing-complete.
The chicken is one of the most common and widespread domestic animals, with a population of more than 24 billion in 2003. There are more chickens in the world than any other species of bird.
Brine shrimp eggs can survive temperatures of liquid air (-310F) and some can survive above boiling temperature (221F) for up to two hours.
The Lammergeier, or Bearded Vulture, lives on a diet of 85-90% bone marrow. Its stomach acid has an estimated Ph of 1 and can dissolve large bones in about 24 hours.
Camel Spiders are actually tail-less scorpions. It has been theorized that the "mice" referred to in the Old Testament were these creatures.
The coconut crab is the largest land-living arthropod in the world, with a weight of up to 9lbs. It breathes with simple lungs and unlike most crabs can drown if immersed in water.
The olfactory bulb in dogs is roughly forty times bigger than the olfactory bulb in humans, relative to total brain size, with 125 to 220 million smell-sensitive receptors.
Deinococcus radiodurans is an extremophilic bacterium, and the world's most radioresistant organism. It can survive over 1000 times a human-lethal dose of ionizing radiation.
Raccoon paws are covered in a horny layer which softens when exposed to water. They often rub items underwater to examine them by touch, giving the appearance of washing their food.
Hedgehogs are birthed with a protective membrade covering their quills, which dries and shrinks over the next several hours.
The rooster serves as a tangible vessel of christ for some as in the gospel of Matthew (26:74-75), Mark (14:71-72) and Luke (22:60-61) in the New Testament with Christ speaking through the cock.
In experiments, rats have demonstrated altruistic behavior. When presented with chocolate chips and caged rats, test subjects would first free the other rat and then share the food.
Penguins are countershaded for camoflage- a predator looking up from below has difficulty distinguishing their white belly from the reflective surface of water, and their dark back plumage conceals them from above.
Mantises, sometimes called "praying mantises", are closely related to cockroaches. Orchid Mantises have been observed displaying paternal care by guarding their eggs, which is unusual among mantids.
Skunk spray is composed of 2-butene-1-thiol, 3-methyl-1-butanethiol, and 2-quinolinemethanethiol. These compounds are detectable by the human nose at concentrations of 10 parts per billion.
Some aphids have telescoping generations- females have a daughter within them (a genetic clone) which is also in the process of producing her own daughter.
The Driver ant's jaws are extremely powerful and can retain their grip even when the ant is torn in half. East African soldiers sometimes use the ants as makeshift surgical staples to hold wounds together.
Unlike horses, oxen are not easily able to balance on three legs while a farrier shoes the fourth. In England, shoeing was accomplished by throwing the ox to the ground and lashing all four feet to a heavy wooden tripod.
The Talmud speaks of learning "courtesy toward one's mate" from the rooster. This might refer to the fact that when a rooster finds something good to eat, he calls his hens to eat first.
Fossil studies suggest that the domestication of dogs took place between 14,000 and 31,700 years ago. In 2001 there were estimated to be 400 million dogs in the world.
The pistol shrimp snaps a specialized claw shut to create a cavitation bubble which reaches speeds of 60 miles per hour and releases a sound reaching 218 decibels. The pressure is strong enough to kill small fish.
Most attempts at training zebras for riding have failed, due to their tendency to panic. In 1907, Rosendo Ribeiro, the first doctor in Nairobi, Kenya, used a riding zebra for house calls.
Baboons are able to acquire orthographic processing skills, which form part of the ability to read.
In 2003, researchers found one species of dung beetle navigates by using polarization patterns in moonlight. The discovery is the first proof any animal can use polarized moonlight for orientation.
The classification of batoids is currently undergoing revision; however, molecular evidence refutes the hypothesis that skates and rays are derived sharks.
Because of their slow metabolism, large komodo dragons can survive on as little as 12 meals a year, but can eat up to 80% of their body mass in one sitting.
In April and May, alligators form so-called "bellowing choruses". Large groups of animals bellow together for a few minutes a few times a day, usually one to three hours after sunrise.
An elephant's trunk contains up to 150,000 separate muscle fascicles and is capable of storing 2.2 gallons of water or cracking a peanut shell without breaking the seed.
Rattlesnakes are able to detect thermal radiation emitted by warm-blooded organisms in their environment and can detect temperature changes of 0.003C or less in its immediate surroundings.
The box jellyfish has 24 eyes, two of which are capable of seeing color, and four parallel information processing areas or rhopalia that act in competition.
The stoplight loosejaw has a unique vision system which uses a derivative of chlorophyll as a photosensitizer that absorbs long-wave light and then indirectly stimulates the fish's two visual pigments.
Pigeons have no gall bladders. Some medieval naturalists concluded they have no bile (gall), which in the medieval theory of the four humours explained the allegedly sweet disposition of doves.
Beavers practice alloparental care, in which an older sibling may take over the parenting duties if the original parents die. This behavior is seen in many other animal species such as the elephant and fathead minnow.
Skinks in the genus Prasinohaema have green blood due to a buildup of the waste product biliverdin.
The skin of naked mole rats lacks a key neurotransmitter that is responsible in mammals for sending pain signals to the central nervous system. The naked mole rats feel no pain when they are exposed to acid or capsaicin.
The total brain-to-body mass ratio of crows is equal to that of great apes and cetaceans, and only slightly lower than in humans.
Giant clams live in symbiosis with photosynthetic algae that grow in their tissues. Adult clams get 70-100% of their nutrients from the algae and the rest from filter feeding.
The blobfish lives at depths between 2,000 and 3,900 ft where the pressure is several dozen times higher than at sea level. Their flesh is primarily a gelatinous mass with a density slightly less than water, giving them bouyancy.
The severed head of a cockroach is able to survive and wave its antennae for several hours, or longer when refrigerated and given nutrients.
The silk moth- the adult form of the silkworm- is unable to fly and has reduced mouthparts which are incapable of feeding.
In 2011, cicadas were incorporated into a single batch of ice cream in Columbia, Missouri at Sparky's. They were advised by the public health department against making a second batch, a suggestion with which store owners complied.
Aristotle wrote the earliest known inquiry into the natural history of eels, speculating that they were born of "earth worms", which he believed were formed of mud, growing from the "guts of wet soil".
Many earthworms can eject coelomic fluid through pores in the back in response to stress; Australian Didymogaster sylvaticus (known as the "blue squirter earthworm") can squirt fluid as high as 12 inches.
G.E. Gates spent 20 years studying regeneration in a variety of earthworms, showing that it is theoretically possible to grow two whole worms from a bisected specimen in certain species.
The naked mole rat and the Damaraland mole rat are the only known eusocial mammals. Only one female (the queen) and one to three males reproduce, while the rest of the members of the colony function as workers.
Although hippos lie close to each other, they do not seem to form social bonds except between mothers and daughters, and they are not social animals. The reason they huddle close together is unknown.
In 1932 the Australian army attempted to cull Emu populations in what came to be known as the Great Emu War. After expending 2,500 rounds of ammunition over six days the death toll was "perhaps a dozen birds".
A termite queen can live for 45 years, producing 20,000 to 30,000 eggs a day. Freshly hatched young appear as tiny termites that grow without significant morphological changes.
Betta Splendens females frequently eat their own eggs shortly after spawning. For this reason, males chase females away and carefully guard the bubble nest they construct to protect them as they incubate.
The silver fox was domesticated in Russia after a 45-year selective breeding program, which also resulted in traits appearing that are frequently seen in domestic animals, such as pigmentation changes, floppy ears, and curly tails.
Many earwig species display maternal care, which is uncommon among insects. Female earwigs may care for their eggs, and even after they have hatched as nymphs will continue to watch over offspring until their second molt.
Male honey bees are produced from unfertilized eggs, so represent only the DNA of the queen that laid the eggs- they have only a mother. They also lack stingers.
The aptly-named hercules beetle can reach over 6.75 inches in length and can lift more than 850 times their own weight.
