A glance at a star-nosed mole (Condylura cristata) is enough to convince most people that something very strange has evolved in the bogs and wetlands of North America. There’s nothing else on the planet quite like this little palm-sized mammal. Its nose is ringed by 22 fleshy appendages, called rays, which are engorged with blood and in a constant flurry of motion when the animal searches for food.
What is this star? How did it evolve and what is it for? What advantage would be worth sporting such an ungainly structure? To a neuroscientist interested in sensory systems, this kind of biological anomaly represents an irresistible mystery. I first began studying star-nosed moles in the early ’90s in an attempt to answer some of these basic questions. But I soon discovered that this unusual animal, like many other specialized species, could reveal general principles about how brains process and represent sensory information. In fact, star-nosed moles have been a gold mine for discoveries about brains and behavior in general—and an unending source of surprises. The most obvious place to start the investigation was with that bizarre star.
Some bacteria can be beneficial, while other bacteria causes illness and even death.Some types of bacteria cause more harm to humans than others, overwhelming your body’s defenses and frequently causing death in terrifying ways and at alarming speeds.
- Bacillus Anthracis: Also known as anthrax, can enter the body via three avenues: through the skin, into the lungs or down the digestive tract. Of these three methods, inhalation anthrax is the most deadly, with symptoms resembling those of the flu or a cold. The Centers for Disease Control and Prevention (CDC) classify anthrax as a Category A agent, the most dangerous group of pathogens, or disease-causing organisms.
- Clostridium Botulinum: Clostridium botulinum causes a severe form of food poisoning, with most cases arising from improper canning methods. The U.S. Food and Drug Administration (FDA) notes that acidity or high heat will kill the bacteria. Once inside the human body, the bacteria start producing toxins, or poisons. Just a minute amount of toxin can make you ill with botulism.
- Escherichia Coli: The infamous E. coli normally inhabits the intestines of healthy individuals. Sometimes, certain strains, or forms, of the bacteria arise that become detrimental to humans, especially the very young, immune-compromised or elderly. One rare, dangerous strain causes bleeding in the intestines. This strain produces a toxin which causes humans to lose blood and other fluids, resulting in dehydration and possible permanent kidney damage in children and death in older adults.
- Flesh-Eating Bacteria: Also called necrotizing fasciitis, flesh-eating disease occurs when bacteria consume human tissues lying under the skin, causing death of tissues and fatalities in a short amount of time. There are many pathogens that can cause this extreme disorder, one of which is the same kind of bacteria that causes strep throat.
- Clostridium tetani: The bacterium causing tetanus, can exist almost anywhere while their spores can remain inactive in soil. When a wound introduces the spores into the deep recesses of the body, the bacteria become active, producing toxins which affect the nerves. The muscles of the body contract sporadically, injuring muscles and bones and causing locking of the jaw.
Worker honeybees shuttling between foraging and nursing tasks have been found to switch huge groups of genes on and off in their brains for each job. This shows for the first time that different behaviours can have specific gene patterns. The discovery could have implications for how our own behaviour influences which genes are switched on in our brains and bodies.
It’s well known that small animals have short life spans while larger ones live longer, and anyone can measure a bird’s heart racing at 300 beats per minute, or an elephant’s plodding along at 30 beats per minute. From this, you might assume that every creature is allocated a set number of heartbeats—say, one or two billion—and just spends them over different amounts of time. This concept is enticing, but not strictly true. There is, however, a link between resting heart rate and life expectancy, and in turn, a link between metabolic rate and life span. In 1932, animal scientist Max Kleiber plotted the first accurate measurements of animal size versus metabolic rate. He discovered that as the life span lengthens, the metabolism slows down, and so he devised a scaling law that linked them, now known as Kleiber’s Law: RM^3/4, where R is metabolic rate and M is body mass. For example, a cat 100 times heavier than a mouse only has a metabolic rate around 32 times greater, meaning it only requires 32 times as much energy to sustain itself. This law holds true with remarkable precision from the smallest bacterium to the blue whale, and it thought to be derived from the mathematical and geometric nature of the circulatory system, and how the system distributes nutrients. The larger the animal, the more energy-efficient it is.
Ophiocordyceps unilateralis is an incredible parasitoidal fungus that actually alters the behaviour of its host to the extent that affected individuals are often called ‘zombie ants’. Once infected, the host ant will blindly leave its colony, and will climb to extraordinarily specific locations (around 25cm from the ground, 94-95% humidity, 20-30 degrees Celsius, on a vein on the underside of a leaf on the north side of the plant - prime conditions for unilateralis' growth). Having reached its destination, the ant is forced to bite down with 'abnormal' force, and is then killed by the fungus (which is what makes unilateralis parisitoidal rather than parisitic). The fungus then extends a stroma stalk, and releases spores which go on to form the next generation.
It has been known to wipe out entire colonies, and as such infected ants are quickly scouted and carried far away from the colony in order to avoid the contamination of the entire colony.
Giant Kelp (Macrocystic pyrifera) is one of the fastest growing organisms on earth, and can grow up to 2 feet every day! It is harvested by humans primarily for alginate, but it also provides for many marine animals who depend on it for food or shelter.
Panther Chameleons (Furcifer pardarlis) are one of 160 species of chameleon that are found in all kinds of habitats, from mountainous and tropical rainforest to deserts and savannah. As evidenced above, sexual dimorphism is prominent in this particular species, with males being up to twice as large and far more vibrant than their generally tan female counterparts. A common misinterpretation is that a chameleon solely changes colour to match that of his surroundings - it also has functions in social signalling, as a reaction to environmental pressures and even thermoregulation.
The Panther Chameleon is often named after the region it is found in, and each region tends to produce chameleons of a certain colour - Nosy Be chameleons, for example, are typically a striking blue, whilst Tamatava individuals are primarily red. Like all other chameleons, F. pardarlis has distinctive eyes that are able to move independently of one another, with only the pupil of each eye exposed. Their tongues are often longer than their bodies. When females are carrying eggs, they turn darker in order to deter potential males, and because of the stress that egg laying puts on their bodies, they only live 2-3 years after laying 5-8 clutches. Which is super sad.
The Giant Panda is one of the most iconic, well loved and protected endangered animals, and is considered a national treasure in its native China, appearing as the five Fuwa mascots of the 2008 Beijing Olympics. They are the rarest species of bear alive, and live almost exclusively on bamboo (though they are included in the order Carnivora) residing in bamboo forests in mountainous Central China.
Whilst 99% of the Giant Panda’s diet is herbivorous, it still possesses the digestive system of a carnivore, and as such, receives little protein and energy from the bamboo it consumes. This is because the polysaccharide present in bamboo, called cellulose, cannot be digested by carnivores. The Panda’s ability to break it down is because of certain microbes present in its gut, and is uniquely adapted to bamboo forests - however, this requires an enormous 20-30 pound bamboo intake every day, and forces the Panda to assume a rather sedentary lifestyle.
There are thought to be 1000-3000 Pandas left in the wild. Their main threat, unsurprisingly, is habitat loss due to human activity, and though 61% of China’s pandas are protected in around 50 reserves, the very low captive and wild birthrate (which tends at most to be a single cub every two years) does not lend itself well to survival. Indeed, captive breeding has only been achieved recently, as individuals seemed to lose all desire to mate once captured, to the extent that viagra was administered to males in desperation. Poaching is an ever-present threat, though the incredible awareness of the protected status of the bear has reduced hunting.
Bowerbirds make up the family Ptilonorhynchidae, which contains 8 genera, all of which are polygynous apart from the genus Ailuroedus. This 20-species strong family is best known for the behaviour of its males, who build and decorate spectacular shelters known as ‘bowers’ in order to attract potential mates. These bowers may take as long as 10 months to complete, and often picky females will visit and revisit many before deciding on the most suitable. Often each species will show a particular style - for example, the Tooth-billed Bowerbird decorates his stage with overturned fresh green leaves. Most of the species are sexually dimorphic, though there are exceptions, and some (such as MacGregor’s Bowerbird) are superb vocal mimics. These passerines are native to Australia and New Guinea.
The Vogelkop Bowerbird (shown above) is perhaps the most ambitious; his drab olive colouring is countered by the elaborate bower he builds. Many times the size of the actual bird, the hut-like structure is complete with a ‘lawn’ of moss and a large number of artistically arranged items. Unusually, there is no common ‘trend’ amongst Vogelkop Bowerbirds - the emphasis instead is on ‘novelty value’, which often leads to theft between bowers of particularly desirable items. The sexes are very similar, though the male is slightly larger than the female.
The Satin Bowerbird is sexually dimorphic, however. The male is an iridescent black, and though the female is more dull, her violet eyes are striking. These birds tend to focus on orange and blue decorations for their displays, with the focus turning more towards blue as they mature.